/ohm/ - electronics general, board af edition

[Anonymous No.1261407]

bump limit reached on old thread >>1256544

https://www.wiki.printf.pl/index.php?title=Pasta (fresh)

>I'm new to electronics, where to get started?
There are several good books and YouTube channels that are commonly recommended for beginners and those wanting to learn more, many with advanced techniques. The best way to get involved in electronics is just to make stuff. Don't be afraid to get your hands dirty.

>What books are there?
Beginner:
Getting Started in Electronics Forrest Mims III
Make: Electronics Charles Platt
How to Diagnose Fix Everything Electronic Michael Jay Greier

Intermediate:
All New Electronics Self-Teaching Guide: Kybett, Boysen
Practical Electronics for Inventors: Paul Scherz and Simon Monk

Advanced:
The Art of Electronics by Paul Horowitz and Winfield Hill

>What YouTube channels are there?
mjlorton
paceworldwide
eevblog
EcProjects
greatscottlab
AfroTechMods
Photonvids
sdgelectronics
TheSignalPathBlog

>What websites feature electronics projects or ideas?
http://adafruit.com
http://instructables.com/tag/type-id/category-technology/
http://makezine.com/category/electronics/

>Where do I get components and lab equipment from?
ladyada.net/library/procure/hobbyist.html
Search the web for "hobbyist electronics sources" to find plenty.
In the US and elsewhere, mouser.com, digikey.com, arrow.com, newark.com are full-line distributors that entertain small orders.

>What circuit sim software do you use?
This mostly comes down to personal preference. These are the most common ones though:
NI Multisim
LTSpice
CircuitLab
iCircuit for Macs
CircuitJS (quick, dirty, interactive)

>What software should I use to layout boards?
Circuit Wizard
ExpressPCB
EAGLE
KiCad

>Q1. Lithium batteries
Will explode if you abuse them. Read and understand all relevant datasheets and be prepared for catastrophe. See
batteryuniversity.com/learn/
>Q2. My circuit doesn't work. Halp?
Check wiring, soldering, part pinouts, and board artwork if applicable, then post schematic.

[Anonymous No.1261409]

>>1261407
this bread brought to you in part by the MCP1407 low-side MOSFET driver

[Anonymous No.1261415]

Which one of these looks less likely to explode and kill me?
https://www.aliexpress.com/item/x/32818833678.html
https://www.aliexpress.com/item/y/32804747875.html

[Anonymous No.1261439]

>>1261415
A good grounded metal enclosure and proper fusing would probably make more of a difference between explosion and death. Anyway, between those two, I'd go for the one with the shrouded terminals, but tbqh I'd prefer
https://www.aliexpress.com/item/Seven-Neon-Free-shipping-high-quality-ultra-thin-AC100-240V-DC-36V-5A-180W-led/32801999625.html
for just a few burgers more. One, the metal guard, and two, inputs and outputs at opposite ends.

[Anonymous No.1261508]

I have a retarded question that I am very ashamed to ask. I want to measure the 12V output of an old pc power supply I have because I'm curious to see how noisy it is. As can be seen it pic related, it supplies 12V at 49A. I have a tektronix 2024 o-scope which has a 1MOhm input impedance. Is it safe to do? The power dissipated by the 1MOhm input impedance would be like 144uW.

[Anonymous No.1261509]

>>1261508
i knew I was going to forget the pic

[Anonymous No.1261514]

>>1261508
Should be. There's usually an input limitation printed near the input connector or in the manual of most test equipment. For that model, it's apparently ±400V.
Two considerations:
Beware of ground loops.
You're going to want to put some actual load on the power supply in order to replicate standard operating conditions. Kitchen electrics such as kettles or griddles are good choices.

[Anonymous No.1261532]

>>1261508
yea, most scopes will be fine at low voltages, its only when you get really high like you need 10x probes. there should be a switch on them to go from 1x to 10x

[Anonymous No.1261534]

>>1261509
also amp rating is the max continuous current draw, not what amount of current is being fed into the scope. you would need a dead short to get something even close to the max current output.

[Anonymous No.1261566]

>>1261514
>For that model, it's apparently ±400V
... and he should be using 10:1 attenuator probes in any case, so that if something gets burned, it's the probe.

[Anonymous No.1261664]

>>1261508
Lookup 'atx power supply start up' about the power-on signal
Good read: Converting Computer ATX Power Supply to Lab Bench Power Supply
http://jumperone.com/2012/12/converting-atx-power-supply-to-bench-power-supply-faq/

[Anonymous No.1261681]

>>1261508
>retarded question that I am very ashamed to ask
There are no retarded questions anon, only retards afraid to ask.

>Is it safe to do?
Yes, should be. But for added safety, you should consider isolating the earth pin on your oscilloscope plugin. Just put a bit of electrical tape on the ground pin of your oscilloscope plug and that should get rid of any ground loops.

[Anonymous No.1261682]

>>1260762
Anyone played with a Minnowboard before? I'm making progress with getting the flash chip to communicate with my mcu.
It will give me the JEDEC id and chip info reliably, but when I try to read the memory, I get different results every time.
My micro hdmi cables should arrive today, so that will help.

[Anonymous No.1261689]

>>1261681
> for added safety, you should consider isolating the earth pin on your oscilloscope

is this some fucked-up meme? while there are occasionally good reasons to unground a scope, 99.9% of the time it should be grounded, like ALL your test equipment. for safety, for noise suppression, and just for consistency of conditions with the rest of the planet.

[Anonymous No.1261698]

>>1261682
you need an SD card anon
https://minnowboard.org/tutorials/installing-ubuntu-16.04-on-minnowboardmax

[Anonymous No.1261700]

>>1261472
the esp8266 can be programmed and function as an independent IoT microcontroller without the mega
https://github.com/esp8266/Arduino

[Anonymous No.1261740]

>>1261698
I did that a few months ago, with no results displayed on the monitor. When my microhdmi cable arrives today, I will try again with imaging an SD card with Ubuntu.

[Anonymous No.1261746]

I need a replacement charger for my electric shaver. The OEM charger is 4.3V. I was looking around on Amazon and this one https://www.amazon.com/T-Power-Multigroom-Sensotouch-Smarttouch-Cool-Skin/dp/B019HVZQJW/ref=sr_1_3?ie=UTF8&qid=1508258217&sr=8-3&keywords=philips+norelco+multigroom+3100+charger
specifically lists my model as being compatible, but that charger has a 15V output. What gives? It's a two-conductor DC charger, so it's not sending data to any smart charging circuitry. Is there a zener or something in the shaver that'll keep it from being overcharged and damaging the battery?

[Anonymous No.1261789]

>>1261689
Its possible that the ground rail in the power supply isn't correctly referenced to earth ground and is actually floating a few volts above it. This is because the output ground is only capacitively coupled to the line neutral and by extension, to earth ground, through a class Y capacitor.

If this is the case, then connecting the oscilloscope ground (which is directly referenced to earth ground via a shunt on the oscilloscope case to the earth pin on the plug) to the power supply ground can cause a potential difference which has the potential to damage sensitive equipment inside the oscilloscope.

The scope should be ungrounded in 99% of cases where you're using it to measure something earth ground referenced.

[Anonymous No.1261812]

I'm building a rover robot, which will have a couple of controllers (arduino/pi) and a bunch of motors (6-12V). Is it a better idea to have one 12V battery and have buck converters for each device that needs less, or have a couple of batteries (one at 12V and another at 6V)?
Also I was thinking about going with Li-ion. Yes?

[Anonymous No.1261813]

>>1261514
>>1261532
>>1261534
>>1261566
>>1261664
>>1261681
>>1261689
>>1261789
thanks for all the help

[Anonymous No.1261819]

do MCUs CPUs ever experience bugs because of pipeline hazards?
or do they only stall?

[Anonymous No.1261827]

>>1261789

if your scope is ungrounded, then the casing and the BNC connectors could easily become live if you're probing around inside an old TV, for example. and, since your instruments are often connected to the scope, your whole bench is now ready to zap you as soon as you touch something.

if ground loops are a potential problem, you can power the unit under test using an isolation transformer. it's wiser than constantly putting your life on the line with ungrounded equipment.

[Anonymous No.1261841]

>>1261827

from Agilent scope manual, ''WARNING ... do not defeat the power cord ground''

[Anonymous No.1261850]

>>1261819
it may happen with rare, buggy processors.
programming and determinism would basically be possible if this were the case because pipeline hazards are a normal part of operation.
in summary, they just stall.

[Anonymous No.1261852]

>>1261850
*impossible

[Anonymous No.1261862]

i have a question, and im not sure how to explain it

im going to connect this bluetooth receiver to my cars radio, and i need to supply 12v into it

i could just connect it to the 12v pin that feeds the radio and be on 24/7

but i actually want the receiver to turn on only when the radio is on too

any idea where i could connect it

thanks

[Anonymous No.1261866]

>>1261746
Not likely. I think some seller doesn't know what they're on about.

>>1261819
Can happen but usually gets tested out before the design sees silicon.

>>1261812
Li-ion can be harder to manage but may better suit your weight and size requirements. Be sure to protect the batteries against overdischarge or overcharge, ensure your batteries have a protection circuit in case your controls fail, observe specified charge/discharge rates, and use only Li-ion-specific charging circuits.

>>1261862
Some radios have a power output that extends the external antenna (where equipped). You'll need to look at your radio's installation manual.

[Anonymous No.1261879]

>>1261862
Should be low enough power that you can just run it off the car accessory bus and not worry about it.

[Anonymous No.1261889]

>>1261866
>Li-ion can be harder to manage but may better suit your weight and size requirements. Be sure to protect the batteries against overdischarge or overcharge, ensure your batteries have a protection circuit in case your controls fail, observe specified charge/discharge rates, and use only Li-ion-specific charging circuits.
So is there a chip/board that does this off-the-shelf or am I going to have to do it all myself?
Knowledge is power and all that but battery management is not really my focus in this project...

[Anonymous No.1261893]

>>1261879
>what is load dump

[Anonymous No.1261895]

>>1261889
You can buy LiPos for drones on ebay. Battery protectors are available that just plug into the balance plug, and sound an alarm if the charge level goes below the safe point for a LiPo.

[Anonymous No.1261899]

>>1261889
Seriously consider using pre-fabricated packs and chargers for drones as >>1261895 suggested.
Now that you have your 12-16.5V, you can hang step-down converters on the battery bus as needed to get your motor and controller voltages.

[Anonymous No.1261907]

>>1261889
Here, have a shopping list.
http://www.ebay.com/itm/New-L298N-DC-Stepper-Motor-Driver-Module-Dual-H-Bridge-Control-Board-for-Arduino-/191674305541?epid=837340831&hash=item2ca0adcc05:g:WFsAAOxyni9S~v5g is a dual-H bridge motor driver. It's great for newbies, there are plenty of guides on how to use it and it really is rather simple. It's also quite practical; it has a 5V regulator included on the chip, so you can plug it into a power source up to 35V, and then tap 5V power from it for your arduino/other circuitry.
http://www.ebay.com/itm/11-1V-3000mAh-3S-30C-RC-Lipo-Battery-Deans-for-Helicopter-Practicle-Airplane-Car-/172820110390?epid=24007051113&hash=item283ce19c36:g:kqQAAOSw7zlZkW01 is a LiPo drone battery. It has a balance plug (for charging) and a Deans plug, which you can cut off and connect the leads into your motor driver/regulator.
http://www.ebay.com/itm/RC-Lipo-Battery-Low-Voltage-Alarm-1S-8S-Buzzer-Indicator-Checker-Tester-LED-/142065592377?hash=item2113c4e839:g:AcUAAOSwZ4dZJ5LQ is a voltage alarm. It's configured with a button, and will sound a very loud buzzer when the battery voltage drops below the configured limit. It connects into the balance plug on your LiPo.
https://www.ebay.com/itm/iMaxRC-iMax-B3-Pro-Compact-2S-3S-Lipo-Balance-Battery-Charger-For-RC-Helicopter-/172802158295?var=&hash=item283bcfaed7:m:mqKsB8aos4LCuzZvPLNOPiQ is a basic charger. You can plug your 3S LiPo into it, and wait an hour or so for it to charge.
https://www.ebay.com/itm/iMAX-B6-Lipo-NiMh-Li-ion-Ni-Cd-RC-Battery-Balance-Digital-Charger-Discharger-/381282390728?epid=510347785&hash=item58c63392c8:g:hwMAAOSwnipWW~el is a fancier charger, where you can configure target voltage, discharge a battery to a safe storage voltage, charge other stuff than just LiPos, and most importantly, can be hooked up to a car battery so you can drive to a field somewhere and still be able to recharge.

[Anonymous No.1261910]

>>1261895
>>1261899
>>1261907
Thanks a lot!

[Anonymous No.1261912]

>>1261907
3S isn't going to give 12V except at the very top of its state of charge.

[Anonymous No.1261913]

>>1261912
That's true, but he said 6-12V.

[Anonymous No.1261915]

>>1261912
I've done robots with motors that said "12V" and powered them just fine with 3S LiPos. One single volt is only a barely noticeable difference. Certainly less of a hassle than getting a 4S cell and strapping a 12V regulator on it.

[Anonymous No.1261917]

>>1261913
Ah, I figured he had some 6V, some 12V, and maybe some in between.

[Anonymous No.1261920]

>>1261917
Even if he does have 12V, feeding it 9.9 to 12.6V isn't going to do any damage. DC motor "throttle" is controlled by changing the voltage fed to them, so all the difference it'll really make is what the top RPM without any load on the motor will be, and the difference between fully charged and fully discharged won't be severe enough to break anything.

[Anonymous No.1261921]

>>1261920
The voltage difference between fully charged and completely dry are even bigger for 4S

[Anonymous No.1261924]

>>1261917
Yeah i have a 6V stepper, 6V servo, and two 12V brush(less?) as well as the controllers. Still in the design stage though so it's not set in stone. Perhaps it would be better to go for 6V on all motors, then I wouldn't need any buck converters?

[Anonymous No.1261926]

>>1261924
You'd still need at least one to get down from 12V to 6V, and if just one it'd have to be pretty hefty. You could try a 2S pack that delivers 6V-8.2V, if the rest of your electronics can handle it. Also you'd still probably want a buck set to 5V for the logic.

[Anonymous No.1261927]

>>1261893
It's using a reasonably rugged DC/DC brick, doesn't care about short spikes.

[Anonymous No.1261929]

>>1261924
How wide range are the ratings on your motors? Could go 4S Lipo for the main motors, 2S for the servo/steppers and DC/DC for the controller.

[Anonymous No.1261930]

>>1261926
hmm ok. Looks like I have a bit of studying to do. I'm still working on the mechanical side of things so I haven't looked at the electronics in detail.

[Anonymous No.1261933]

>>1261924
Steppers and servos can run just fine on 5V, so unless you desperately need every little bit of torque you can get, I'd hook them into the same 5V regulator you use for Arduino/logic. Brushless motors run just fine on 3S LiPo, so I'm still recommending that. This way you only need one regulator, and you can use off-the-shelf components.

[Anonymous No.1261943]

My Nitecore charger shows a few of my old 18650s 'fully charged' at 1.6v. Are they fucked?

[Anonymous No.1261948]

>>1261943
i'm going to guess yes

[Anonymous No.1261968]

Just discovered this general, really enjoying learning about electronics so far. Are there any good sources to learn about electronics theory? e.g.signal and circuit analysis techniques such as Mesh analysis.

[Anonymous No.1261971]

>>1261968
Fundamentals of Electric Circuits by sadiku
google it. you can find a pdf easily

[Anonymous No.1261976]

>>1261943
>18650s 'fully charged' at 1.6v.
18650s are discharged at <3v

[Anonymous No.1261978]

>>1261968
mit 6002x lectures and free pdf online.

[Anonymous No.1262056]

On the datasheet for the Murata RO3144E-2 916.5MHz SAW resonator, it states:
>The SAW resonator is bidirectional and may be installed with either orientation.
>The two terminals are interchangeable and unnumbered.
Which brings to doubt whether this is an automatic (put in DC, get out AC) resonator, as does the equivalent RLC model. But pic related suggests that it does do this. So assuming pic related works fine and that the upper diagram's transistor is meant to be powered with the binary signal you want to transmit over CW (what I want to do), what kind of values should I be looking at for the inductor and capacitors? If the LC part has to be in resonance (which it better since otherwise we aren't getting a nice siusoid), that means using stupidly small capacitors and inductors, might as well use a piece of double-sided PCB and cut it to size along with a single wrap of wire around a pencil. Parasitics will be a bitch, that I know. The "antenna" shown in that circuit is an inductor, but I was under the impression that a half-wave dipole oscillated its electric field, not magnetic, and that's the antenna I planned on using.

[Anonymous No.1262092]

Can anyone recommend a decent LDR/optocoupler for a VCA?

I want a product that'll give me as fast an attack and release time as possible using this topology.

[Anonymous No.1262093]

>>1262092
Curious, why don't you use an OTA like the LM13700?

[Anonymous No.1262094]

>>1262093
Too much distortion. Not suitable for audio, only speech.

[Anonymous No.1262095]

Has anyone ever made their own high powered LED light?

I found this guide:
https://www.diyphotography.net/building-a-crazy-1000w-led-flashlight/

I was thinking of doing similar with 150w LEDs instead, and mounting them within a reflective cup to make it a spot

[Anonymous No.1262127]

>>1261407
So I'm looking at delving into a few projects in my garage, and while I'm good on the mechanical side of fabricating, I need electronics to make some of those ideas happen.

I don't know enough to know what I don't know, is the problem. So just how deep into the rabbit hole do I have to go in order to build stuff like a solar array and battery system, a basic speed controller for a DC motor, or a motion sensor?

[Anonymous No.1262136]

>>1262092
http://lunainc.com/product/optocouplers/
e.g. NSL-32SR2.pdf, probably expensive, Amazon $12 each.

I made it myself: clear, green, narrow angle 5mm LED, small LDR, black shrink tube. Used for gain control of an unconventional sine/cosine generator, THD was about 0.1%.

Cheap LDRs (1.50 for 5) have a large tolerance, Ron (white LED 5mA) between 800Ω and 1.4KΩ, Roff >40MΩ, can't measure.

[Anonymous No.1262163]

>>1262056
Also if anyone who's dabbled in RF before can recommend a good GHz transistor that would be neat, otherwise I'll just get the cheapest one with a unity-gain above 2GHz.

[Anonymous No.1262170]

>>1262127
As far as I know, there's a bit of a rabbit hole for solar systems, but nothing you couldn't learn in a few month's worth of online articles and experimentation. There's not too much custom electronics in it, typically the best deals are prefabricated circuit boards and everything just fits together for small scale solar, and large scale is a big investment. But just dealing with less than a square yard of panel you could definitely home-brew some stuff without worrying about high-current transistor arrays and such.

Again, motor speed control is typically just a prefabricated circuit board that you just stick your wires into, though that's just a duty-cycle dimmer. If you want an RPM-based speed controller for an induction tool you'll need a variable frequency drive, which could be a very deep rabbit hole, and for a universal/DC motor you'll need some optical doodads and probably a microcontroller, which is a rabbit hole of programming.

A motion sensor is typically done with a microcontroller because people love their fucking arduinos, and if you want to send a signal to a computer it is the best option. But to trigger an alarm, turn on a light, or any other thing that can be accomplished by wiring a battery/wall socket to it, you can quite easily do it. If you have access to both sides of the motion-detection area then you just put an IR LED and IR phototransistor and when something breaks the line of sight from one to the other, you've got yourself a signal. If not, then you have to be a bit more creative, such as ultrasound, radar if you're a spiffy fucker, or trying to read the IR/visible light bouncing off a subject with some sort of lidar.

As far as general electronics knowledge you need, I'd say learn the basics of ohm's "law", the operation of capacitors and inductors in a DC circuit, maybe in an AC circuit too if you plan on sticking things into the wall, then BJT and FET transistors, and studying how simple circuits are made. Also datasheets.

[Anonymous No.1262176]

>>1262056
Nevermind, this extra document says it all. Any clue how you're supposed to find documents that relate to a company's product but aren't on/linked-to on the product's datasheet? I'm starting to wonder if those 1-2 page datasheets on Arrow are hiding something. The query as to a good transistor remains, though looking at the one they picked for a 470MHz resonator, a unity-gain frequency of 4GHz is probably better.

[Anonymous No.1262177]

>>1262176
*15GHz

[Anonymous No.1262186]

>>1262056
>Which brings to doubt whether this is an automatic (put in DC, get out AC) resonator
What makes you even consider that? The transistor is needed, because it's just a resonator, not an oscillator.
L1 forms a resonator with the series connected C1/C2 (and transistor and parasitics). Dimension L1 for around 100 ohm impedance, and C1/C2 to go with your coil. C2 is usually made bigger than C1, for example 3 times.

[Anonymous No.1262203]

>>1262186
I thought that's what "resonator" referred to, as opposed to oscillator. I don't really get how the circuit could be sending feedback to the resonator in the circuit, but I guess it's just through the output current. I guess what I was thinking of was a "plug and play oscillator" as Arrow calls it, but it doesn't look like they're made in the 902-928MHz range, so I'm stuck with resonators. Here's the example circuit with values, for a 470MHz oscillator.

[Anonymous No.1262204]

>>1262203
What I find odd is that L2 and C3 don't resonate at 433.92MHz at all, but 21MHz.

[Anonymous No.1262215]

>>1262163
My urban jungle radio has a BFR93A input stage, 10 for €1.60

[Anonymous No.1262225]

>>1262215
I was looking at the BFR340F, but the 93A has higher maximum voltages and comes in SOT-23 so I'll go for that, thanks!

[Anonymous No.1262239]

>>1262203
Feedback path is Ccb of the transistor.
>>1262204
C3 is for DC decoupling, same value as C5 for BoM reasons. L2 is part of antenna matching (not shown).

[Anonymous No.1262265]

I want to attach some wires to these pots. Should I attach a piece of perfboard to the pins and solder the wires to that, or should I just solder them to the grommet that the pins are attached to?

[Anonymous No.1262266]

>>1262265
directly to the pins

[Anonymous No.1262303]

I'm retarded and can't figure out how to find I1 and I2. I know I3 is -4A, but I can't figure out any of the others.

[Anonymous No.1262318]

>>1262303

do your own homework, faggot, so the diploma they give you will mean something. or, if you must cheat, do it quietly by downloading a circuit simulator. online ones are available too, but less sophisto. check the stickie (first post of this thread).

[Anonymous No.1262320]

>>1262303
I'm a dumbass and figured it out.

>>1262318
My problem was I kept going in circles because I misread the instructions and thought I had to ignore the 8v source for some reason.

[Anonymous No.1262323]

>>1262318
Also, it wasn't homework. It was a problem given out during the lecture.

[Anonymous No.1262327]

Kirchhoff's Ghost - trapped in the Matrix

[Anonymous No.1262373]

Does anyone have a safe for school version of this?

[Anonymous No.1262380]

>>1262170
Thank you anon, this is the kind of general advice I was looking for.

[Anonymous No.1262422]

Hey so maybe you guys can answer a question I've been wondering about since I was a kid. See, my parents used to have this "booster antenna" for AM radio signals, it was basically a big brown cake pan (made of plastic IIRC) with a tuning knob on it. You'd put it next to the radio (there was no connection cable or anything,) tune to a weak radio station and then turn the knob on the antenna to the same frequency and amazingly it would make the signal come in clearer.

How would something like this work? Amazed the hell out of me as a kid because of how the antenna wasn't actually connected to the radio or anything.

[Anonymous No.1262424]

>>1262422
The plastic was likely just a cover, there was probably wire inside.
What it was is a parabolic receptor, a relay, and a transmitter. So basically, a very sensitive radio, that retransmits what it receives instead of making sound.

[Anonymous No.1262432]

>>1262422
one of these with a plastic cover

https://aa7ee.wordpress.com/2013/11/17/a-tuned-loop-antenna-for-the-am-broadcast-band/

If you want to search for more info on this type of antenna, look for 'inductive coupled am booster antenna'

[Anonymous No.1262435]

>>1262373
roll

[Anonymous No.1262439]

>>1262284
a whole lotta fun by the looks of it

>>1262294
depends on your board. check pcbshopper

[Anonymous No.1262458]

i have a 9V alkaline battery that i don't trust. the output voltage drops significantly when a load is attached, so i measured the inner resistance similar to pic related. apparently it's about 35 Ohms

is this thing simply done for? no load voltage is still 8.5V tho

[Anonymous No.1262470]

>>1262303
>he actually uses mesh analysis
any other method than brute force solving a circuit is pleb tier

[Anonymous No.1262475]

>>1262458
ohshitniggawhatareyoudoing.jpg
Those were never meant to handle amps of load.

[Anonymous No.1262481]

>>1262458
9V/2.4A=3.75Ω, not 35Ω
A new 9V battery I tested had about 9.5V open loop and almost 1V across a 0.1Ω load, so less than 1Ω internal resistance. The discharged battery I was replacing had 7.4V and 0.04V at 0.1Ω or about 20Ω.

[Anonymous No.1262486]

>>1262475
What amperage are they good for then?

[Anonymous No.1262491]

>>1262486
The less the better, multimeter, LCR meter and such, a few mA.

[Anonymous No.1262492]

>>1262475
>never meant to handle amps
Test of Ri only takes 0.1 s, scope stores value.

[Anon No.1262496]

I am gonna make an order from aliexpress and order some components like resistors capacitors e.t.c..
Any idea what should I get,
E.g. 1/4w only resistors or 1/2 too? What kind of capacitors? I might need some small ttansistors too.

What do i need those? Welp work on fpgas and i want to make some simple circuits to test my theoretics e.e. knowledge and to learn about pcbs in general, first project would be some fm receiver, some pwm controllers for some motors and so on.
20$ is within my budget for such components.

[Anonymous No.1262522]

>>1262496
$20 is a bit tight.
A good rule when getting started is to order component assortments that contain the components you need for the specific project you want to do, where possible. Make up a design or pull one from the web, then order kits to match. Unless you're way too far off the mark, you'll have components in stock for the next project or next try at this one.
You probably won't need 1/2W resistors unless working with higher voltages or currents. You can always parallel two 1/4W resistors to get the same effect.
FM transmitters from scratch require specific and particularly stable caps such as NPO ceramics, which takes $4 out of your budget, and somewhat specific transistors or an IC designed for the purpose. In this case you should consider a small quantity of the specific values parts needed rather than an assortment.
>motor controllers
IRF520 is a good all-around N-channel power MOSFET, ~$3 for 10. If you're pulling more than an amp or two through them on average, you may want TO-220 heatsinks too.
>fpga experimentation
For this I suggest that you get some level shifters or components to make one, because you will probably need to deal with 5V external signals from time to time and you Vccio is probably 3.3V. There are bidirectional level shifter circuits for e.g. I2C based on a low-Vgs(on) small MOSFET and a couple of resistors, which will work fine in a unidirectional application. It's not a bad idea to just build a few of these on some breadboard pieces and save them in your components box.
You will probably also want a small bag of pin headers and a set of Dupont leads just because.

[Anonymous No.1262546]

>>1262486
>amperage
REEEEEEEEEEEEEEEEEEEEEE

[Anonymous No.1262679]

>>1262475
i never uses it for more than 0.2A

what aee you trying to say?

>>1262481
the picture is only SIMILAR like i said, not the actual measurement....

[Anonymous No.1262761]

>>1261407
I wan't to make a circuit that creates a sine wave with a variable frequency, I specifically wan't to do this without using any microcontrollers or prebuild components. does anybody have any idea's

[Anonymous No.1262769]

>>1262761
>prebuild components
not even transistors?

[Anonymous No.1262770]

>>1262769
no I just mean no prebuild modules

[Anonymous No.1262771]

>>1262761

read this thread: https://www.eevblog.com/forum/projects/function-generator-ics/

[Anonymous No.1262772]

>>1262761
voltage controlled oscillator

[Anonymous No.1262775]

>>1262772
if you can find a voltage controlled sine wave oscillator because I have been searching for this shit a long time ago

[Anonymous No.1262776]

>>1262771
tnx

[Anonymous No.1262779]

>>1262775
im assuming if you made your own vco you could make it sinusoidal

[Anonymous No.1262784]

>>1262779
yea that is what I am trying to do

[Anonymous No.1262805]

>>1262761
www.google.com/search?q=XR2206+kit
look for built-in frequency counter or add one later

[Anonymous No.1262833]

>>1262805

that's pretty crazy. the XR2206 hasnt been manufactured in over a decade. i wonder if they're recovered chips, or fakes.

[Anonymous No.1262838]

TI Store has free shipping & no minimum order quantities during this week. What's /ohm/ going to get? Any suggestions for interesting parts?

[Anonymous No.1262839]

>>1262838
one ULN2004 one hundred times

[Anonymous No.1262840]

>>1262761
http://sound.whsites.net/articles/sinewave.htm#s69

Not all of these topologies are well suited to variable sinewave generators but you're bound to find something that will work out okay for whatever frequency range you want to cover.

[Anonymous No.1262845]

http://sound.whsites.net/articles/sinewave.htm#s69

Not all of these topologies are well suited to variable sinewave generators but you're bound to find something that will work out okay for whatever frequency range you want to cover.

Edit: Most of these are circuits are for low frequency sinewave oscillators, audio range and probably a bit beyond. Once you start getting up into RF in the MHz range you'll need RF transistors and LC resonators. In the GHz range you need more exotic components like tunnel and Gunn diodes, YIG oscillators, heterojunction bipolar transistors, MESFETs. etc.

[Anonymous No.1262847]

>>1262761
http://sound.whsites.net/articles/sinewave.htm#s69

Not all of these topologies are well suited to variable sinewave generators but you're bound to find something that will work out okay for whatever frequency range you want to cover.

Edit: Most of these are circuits are for low frequency sinewave oscillators, audio range and probably a bit beyond. Once you start getting up into RF in the MHz range you'll need RF transistors and LC resonators. In the GHz range you need more exotic components like tunnel and Gunn diodes, YIG oscillators, heterojunction bipolar transistors, MESFETs. etc.

[Anonymous No.1262849]

>>1262761
http://sound.whsites.net/articles/sinewave.htm#s69

Not all of these topologies are well suited to variable sinewave generators but you're bound to find something that will work out okay for whatever frequency range you want to cover.

Edit: Most of these are circuits are for low frequency sinewave oscillators, audio range and probably a bit beyond. Once you start getting up into RF in the MHz range you'll need RF transistors and LC resonators. In the GHz range you need more exotic components like tunnel and Gunn diodes, YIG oscillators, heterojunction bipolar transistors, MESFETs. etc.

[Anonymous No.1262992]

>>1262833
Chips are produced whenever there is a demand. The XR2206 seems to have been produced in 2004, 2009 and 2016, not necessarily by Exar Corp. You can license the fab process of whatever you want and are able to make. This is common practise and there's nothing 'fake' about it. The latest XR2206 datasheet is from 2008. How many companies still produce the µA741 (Fairchild, 1968)?

[Anonymous No.1263029]

Dumb question: I wanted to make some simple/dumb embedded projects for fun, but also thought I could kill two birds with one stone if I could use a microcontroller that uses x86 isa, so I can learn x86. Not surprisingly, Intel makes a MCU that uses x86 and even has a dev board for it.
Is there any reason why it would be bad to learn embedded stuffs using x86? Like, I know it's CISC, but I can't imagine it's too terribly different from how you program a PIC, no?

[Anonymous No.1263135]

>>1263029
I wouldn't touch the x86 micros. CISC is pretty different from RISC, and x86 is pretty different from the 8-bit RISC microcontrollers. The microcontroller variant is probably different enough from desktop PCs to not teach you much about practical x86 programming. tbqh the best tool for learning x86 is the one likely sitting right in front of you.
AVR dev boards are available for less than $10. You can program Arduino boards in asm, no problem.

[Anonymous No.1263144]

>>1263135
> The microcontroller variant is probably different enough from desktop PCs to not teach you much about practical x86 programming. tbqh the best tool for learning x86 is the one likely sitting right in front of you.
Ah, okay, I was kind of wondering about that. I'll just keep my projects separate then. Thanks.

[Anonymous No.1263152]

I want to make a small rc car using 3V dc motors attached to a small breadboard, what batteries would suit my needs best? I'm thinking of just using AA's but idk if there are any better options out there.

I did try google but just got top 10 mini drones lists.

Thanks guys.

[Anonymous No.1263155]

>>1263152
an 18650 lithium would work best for you. buy a charger too. all you have to do is be sure you don't discharge it below 3V, which is easy if you use a microcontroller with an ADC.

[Anonymous No.1263171]

>>1263152

you sound like a bit of a noob, and so you need to avoid lithium (aka lipos, li-ion) at all costs, if you value your life and your eyes. so definitely stick to AA's, but use rechargeable nicads or nimh's so it wont cost as much. you can pick up a charger and 4 nihm's at the dollar store for under $10.

[Anonymous No.1263173]

>>1263152

you sound like a bit of a noob, and so you need to avoid lithium (aka lipos, li-ion) at all costs, if you value your life and your eyes. so definitely stick to AA's, but use rechargeable nicads or nimh's so it wont cost as much. you can pick up a charger and 4 nihm's at the dollar store for under $10.

[Anonymous No.1263181]

>>1263152
You could get a 1S LiPo, they make them in tiny formats for RC helicopters but you'll get a lot of power for a low cost, and they can be charged via USB. You will want to make a low-voltage warning though, but that's pretty easy and there are alarms you could buy for spare change anyway.
Really would be easier to just hook two AA batteries up in series though. A 1S LiPo ranges in output from 4.2 to 3.3V, and 4.2 is enough to damage electronics designed for 3V.

[Anonymous No.1263235]

Do any of you guys know the size of a COMPLEX datatype? I'm programming an FFT in C for a microcontroller and trying to optimize memory use. I can't find info on COMPLEX to compare to 2x floats.

[Anonymous No.1263269]

>>1262239
But a dipole has no net inductance or capacitance at resonance? Inductive antennae or capacitive antennae might also do the trick I guess, but it seems a bit odd. I guess the resonant frequency of an antenna isn't necessarily that of the frequency the dipole is made to run at, but using both an inductor and a capacitor is unnecessary when you could just use one, unless the reactance of the antenna changes enough to need buffering.

Now comes the problem of figuring out correct resonant values for the caps and inductors, for which my 10µH/25pF minimum LCR meter will probably not be too good at. I wonder if they make multi-turn variable caps for this purpose, preferably logarithmic? I'd make my own with a nylon bolt if I wasn't going to make an SMD board. I guess what matters is the keeping ratio of reactance to radiation resistance small.

[Anonymous No.1263275]

>>1263235
just print sizeof()? Or am I missing something?

[Anonymous No.1263286]

>>1263235
complex doubles the size of whatever type you're using it with.

[Anonymous No.1263299]

>looking for projects
>everything is about arduinos or raspberry pi's

[Anonymous No.1263382]

>>1263269
A keyfob with a dipole?. Short Range Devices have no dipole, they either have the antenna printed on the PCB as a closed loop or they have a shortened lambda/4 helical (that's why DC blocking C3). I'd suggest you look for TX, RX or TRX modules, they are cheap, UHF is no diy stuff at that level.

[Anonymous No.1263386]

I need help lads

I have exactly two weeks to master dc and ac analysis of two transistor amplifiers and drawing small signal models

What's the best way to learn?

[Anonymous No.1263401]

>>1263299
Get into radio stuff. I've been getting into it after I got tired of Arduino stuff and learning a ton of stuff, finally figured out how an antenna works. Built a radio recently using a coil wound on a cardboard cylinder and variable capacitor using two pieces of paper with aluminium foil on them and a peizo crystal as the speaker. Works well and is fairly tunable and picks up a couple of AM radio stations.

[Anonymous No.1263404]

>>1263299
So make the same projects without using a microcontroller to cheat.

[Anonymous No.1263407]

>>1262838
ayyy bretty gud
So many choices. I'm going with some low voltage op amps, a little little logic, and a PMIC I've been meaning to play with.
I sure do wish one of the full-line distributors would offer free shipping some week.

>>1263299
don't you hate that? see
>>1262373

[Anonymous No.1263423]

Not sure if the right board/thread, but I'll ask anyway
My headphones has sound coming out of one ear.
If I twist the end of the wire(the part which goes into the computer), I can hear both. So something is wrong at the end, right? Can I fix it myself by cutting it open and somehow connecting the loose wires or do I have to give it to someone to fix?

[Anonymous No.1263424]

>>1263423
Headphone cables are almost unrepairable due to wire thinness. Plan on replacing the entire cable assembly

[Anonymous No.1263425]

>>1263386
BJT transistors btw

[Anonymous No.1263426]

>>1263423
Yeah, usually you can fix them, but sometimes the wire is nearly impossible to solder.
Googling "fix broken headphones" produces plenty of results.

[Anonymous No.1263455]

>>1263423
It's doable, but there are some quirks. The wires are really thin and laminated, use fire to burn that off. Be sure you get the right wires connected to eachother too.
In the future, consider buying headphones that have detachable cables.

[Anonymous No.1263460]

>>1263455
>detachable cables
preferrably for standard 3.5mm plugs

[Anonymous No.1263543]

Why does my flyback converter hate me? I've tried to simulate this on multisim and no matter what I did I either got convergence errors or an incorrect output voltage (should be around 170-180V out, 12V in). I figured I'd redo it in PSpice and see if I could get better results but no dice.

Is it the design? Or is it just simulators being finicky?

[Anonymous No.1263579]

>>1261407
anyone good with an arduino able to answer a stupid question.
I have a clone arduino uno, when I set the baud rate to anything over 9600, (14400 is the next one) I get junk printed to serial.

[Anonymous No.1263581]

>>1263543
It hurts.

[Anonymous No.1263584]

>>1263579
you sure you set this to the same rate you did in your code Serial.begin(####); ?

unrelated:
>drilling holes into PCB
>using 1mm bit and hand powerdrill
>bit snaps
>"fuck, I was almost done!"
>"hmm, the broken bit must have sharp edges"
>keep drilling with broken bit
>it moves a lot when starting the hole
>after initial hole is made it drills no problem

[Anonymous No.1263595]

>>1261407

hey guys, if any of you know about ionized type air purification, or just the science in general, could you come here and help determine if this shit is snake oil or not?

i know that ionization can clean air, but what i want to know about is this hokum technology from the advertising. is it based on reality, or is it just a case of the marketing department realizing that their shit isn't special so they make up shit about nickel catalysts and stuff to seem "superior"

>>1258847

[Anonymous No.1263607]

>>1263595
loaded pseudo question. build one and find out on your own.

[Anonymous No.1263617]

>>1263584
shit, now I find I still need two more holes

[Anonymous No.1263620]

>>1263595

yes it works, but no, it's not that great. also, the number of ions being emitted decreases with time as the sharp pinpoints needed to expel them become blunt.

how it works: a very high voltage is generated and applied to sharp points. the electrons, being self-racist, try to get away from each other and jump off the points into the air. if they collide with particles (of smoke, dust, or whatever) they stick, the whole thing becomes heavier and falls, or sticks to walls.

[Anonymous No.1263636]

>>1263581
I don't get it. I need feedback to ensure the output voltage is regulated and since the output voltage is relatively high I need isolation so I either need a transformer feedback winding or opto-isolator. I choose the latter.

The way I see it the LED converts current to light which the phototransistor picks up and converts back to current, the op-amp below is current to voltage conversion which is integrated against the reference voltage, originally intended to be 1.2V but there were limitations with the TL431 so I settled for the lowest voltage I could get.

Is that not how to use the opto in feedback?

[Anonymous No.1263662]

>>1263636
>The way I see it the LED converts current to light which the phototransistor picks up and converts back to current
Im not an expert on those devices, but I doubt that conversion is linear, most time I've seen them used was for digital signals.

[Anonymous No.1263731]

>>1263636
Your design has some problems.

[Anonymous No.1263734]

I've been playing with this LED driver circuit. It is originally from an STMicro application note. I just modified it to suit PNP transistors and added an "enable" input that could be used for on/off control (or maybe PWM dimming). Is there any problems with this kind of approach?

[Anonymous No.1263736]

>>1263543
I stopped counting the absurdities. Didn't you smell that (as drawn) M1 has long since saturated the core and is now dissipating 65 watts? Why transformer and optocoupler when the entire circuit has a common 0? Is this an advanced troll circuit?

[Anonymous No.1263746]

>>1263734
Should work. Supply could be a bit tight, LED has 3.6..4V at 20mA, typical 3.5V at 18mA. BD136 is overdone, BC327 would do. R3 should be 2K2.

[Anonymous No.1263784]

>>1263620
>the electrons, being self-racist, try to get away from each other

i love this board

[Anonymous No.1263811]

Anyone know what happened to photonicinduction? He got married but seems to have fucked off again.

Also I think I found his house in street view.

[Anonymous No.1263867]

>>1263736
The entire circuit actually does not, or rather is not intended to have a common ground. Simulation programs tend not to play nice with floating returns so I literally have to reference all grounds to the same node. This may be more of an issue in multisim than it is with PSpice but rest assured the high and low voltage sides will not share a common ground in the actual circuit.

[Anonymous No.1263891]

>>1263867

used to be you'd spend 10 hours massaging a circuit into behaving. now you spend 20 hours massaging the simulator, then another 10 on the circuit itself. this must be progress.

[Anonymous No.1263903]

>>1263386
open a book and do all of the relevant problems. life isn't like candy crush, get to work.

[Anonymous No.1263904]

>>1263867
you can weakly reference them to global 0 with a 100 ohm resistor or something. it's fiddly, but can work. otherwise you just have to be smarter than the simulation.

[Anonymous No.1263905]

Is there a way to buy a 2S1P 8.4V case with over-discharge protection for 18650s to be removed frequently or do I have to make one myself?

[Anonymous No.1263914]

>>1263905
surprisingly, or not, there is.
ebay com/itm/1-x-2S1P-7-4V-18650-Holder-Case-Battery-w-Li-ion-PCM-Protection-Circuit-Module-/152664095459

[Anonymous No.1263925]

>>1263914
I was looking at that before but
https://www.fasttech.com/forums/1279500/t/1038346/getting-the-output-7-8v-using-9v-battery?1076293

[Anonymous No.1263941]

>>1263925
Oh, there is that. I guess you will have to roll your own. Looking at the DW01 datasheet, you might be able to play some games with the charge sense input using a switched capacitor arrangement and a push button.

[Anonymous No.1264015]

I'm looking to make my own mouth fedora
>inb4 explosive device

I want it to be relatively safer by putting in a mosfet and resistors. Problem is I can't buy any cheap hammond 1590G's. There are some 1590A's, but they're a bit smaller.

Is it possible for everything to fit in such a small enclosure (wires/510/anti-vandal push switch/2x single battery bays / mosfet + resistors)?

pls no bully

[Anonymous No.1264048]

>>1263662
you're right. many devices use a zener or a tl431 as a secondary side feedback loop to drive the optocoupler

[Anonymous No.1264069]

>>1264048
Of course. You don't ruin the signal you want to use. Why not start with something simple (pic). U·t = I·L and t = ln(2)·R·C plus RTFD of the 555 regarding pin 5.

[Anonymous No.1264072]

I removed this LCD from something that broke. How would I find out if it's fried and how would I go about connecting it to a raspberry pi? Also how could I power it?

[Anonymous No.1264082]

>>1264072
The easy way it to look up for a control board on ebay/aliexpress for this particular LCD model, they are generally quite cheap (between 20 and 30 usd).

The 2-pin connector is for the backlight, probably a cold cathode lamp which require a dedicated high-voltage ac power supply generally called "inverter board". The other connector is yet another LVDS standard (not eDP) to actually drive the LCD (interesting read: http://jared.geek.nz/2015/apr/driving-fpdlink-displays).).
So in other words, hope that panel is relatively common so you can find a control board kit easily, otherwise it's going to be a pain.

[Anonymous No.1264127]

I bought a kit and it includes some 0201 resistors. HOLY SHIT BATMAN! A fucking breadcrumb is bigger than shit shit. How the fuck do I solder something this small???

[Anonymous No.1264133]

>>1264127
http://www.circuitrework.com/guides/7-3-1.html

[Anonymous No.1264136]

>>1264127
Surgical loupes, smallest tweezer you can find, microliter pipette to apply solder paste and hot air gun.

[Anonymous No.1264143]

Hi, I know something about electronics from my degree, but more about microelectronics, I recently bought a soldering iron I want to do something audio related.
For start, I want to try to do an rca input switch 3 intputs one output, I have a 4 pole 3 way rotatory switch that someone gave me. But I am not sure what I have to do. Do I have to switch the grounds from diferent inputs or could it be shared?
If I put it in a metal case, do I need to conect ground to the case?
If I want to switch between 2 running sources do I need some extra element for protection? I mean is it possible to add something to supress the click noise(bad for speakers) when conecting a new source with the amp running?

[Anonymous No.1264154]

>>1264143
If you put it in a metal case, I'd advise against having any conducting element in contact with the case. It's just too easy to end up frying something with an accidental short circuit. Use motherboard spacers and m3 nuts and bolts to mount your circuitboards safely.

[Anonymous No.1264164]

>>1264143
Shared ground, all inputs terminated, e.g. 100K signal to ground. No hot-plugging.

[Anonymous No.1264184]

>>1264015

Modern MOSFETs aren't designed or terribly suitable for linear applications any more and if it fails short it won't make you any safer. If you do this make sure you know how to read the MOSFET's datasheet's SOA. A mod using high current DC/DC converters might be an alternative (dunno, not my scene).

As for the box, look up datasheets for the 1590A and a dual 18650 battery holder and match dimensions ... I'm having a really hard time not bullying here, since you obviously didn't do this. It won't fit. You might be able to find a RC pouch cell/LIPO pack which can handle the current and fits.

PS. lithium batteries aren't really explosive devices, they just have the potential of suddenly venting hot chemicals and molten metal into your face.

[Anonymous No.1264195]

>>1264184
>Modern MOSFETs aren't designed or terribly suitable for linear applications
Generally true, but you can still get mosfets designed for linear applications, for example IXYS's Linear L2 series. They tend to be rather expensive, though.

[Anonymous No.1264270]

>>1263746
Thanks for your suggestions. I did not have a LTSpice simulation model for BC327 so I used an 2N2907A as I have a couple of those.
I made a simulation by sweeping the supply voltage from 10 V to 30 V and noticed the LED current varies by a couple of milliamps (~16..19 mA with shown component values). While this simple circuit already does a pretty good job at regulating the current, I feel there's still some room for improvement. Are there any ways to improve the current regulation?

[Anonymous No.1264279]

>>1264270
Turn Q3 to constant current sink, replace D7/D8 with something more stable, lose more voltage in R1/R2/R6/R7.
Why do you even want to use PNPs?

[Anonymous No.1264292]

i used to have a link to a trace-to-trace leakage estimator. does anyone know of one? i can't find it again.

>>1264184
i don't know vapes but i assume the heating element is some nichrome, not the mosfet itself, so presumably the mosfet would be pwm driven rather than linear.

[Anonymous No.1264323]

>>1264270
>any ways to improve the current regulation?
Sure. I was dealing with the tolerance of the LEDs (3.6..4V at 20mA) and the 12V limit. If you already have these LEDs you can measure the real Vf vs Id you got and take that into account. Pic shows a way to actively regulate the LED current.

[Anonymous No.1264341]

>>1264279
>>1264270
>Turn Q3 to constant current sink
Transistors are cheap..

[Anonymous No.1264345]

>>1264279
>Q3 to constant current sink
Done. Transistors are cheap.

[Anonymous No.1264380]

>>1264184
ok thanks anon

>>1264292
Heating element used can vary from kanthal, nichrome, stainless steel, ceramic, and so forth.

I'm planning to use the mosfet on the switch since most switches can't handle the current being used or required for dual batteries thus heating them up.

[Anonymous No.1264799]

sooooo, I'm trying to control a speaker with an arduino (digital input-> arduino plays a certain sound recording). Is there a way to do this with just the arduino or do I need a module like this: (especially bc arduino has close to no saving space):https://www.ebay.com/itm/TF-Card-U-Disk-Mini-MP3-Player-Audio-Voice-Module-Board-For-Arduino-DFPlay-/191823187498?epid=733086247&hash=item2ca98d8e2a:g:sskAAOSwAuNW3TWw


Or do you think it makes more sense to buy a mp3 player straight up (cheapo ones, like this: 1€ p.p. https://i.ebayimg.com/images/g/0KEAAOSwu4BVkLJE/s-l1600.jpg ) and connect the buttons to the arduino

[Anonymous No.1264806]

>>1264799
You could store the sample in processor's program flash and output it via PWM. You can store some seconds of sound that way, but playback quality is pretty low.
There are also sound recorder ICs which do the same job, for example Nuvoton's ISD series. Dunno how much they suck nowadays.
You can also get ready-made (greeting card) sound recorder modules for cheap. Sound quality and the amount of memory varies.

[Anonymous No.1264831]

>>1264799
Why not just buy an old Walkman and do it with a tape cassette?

[Anonymous No.1264842]

>>1264323
>>1264345
I haven't done any prototypes of this circuit yet. But with your arrangement the simulated variation in LED current is just 30 μA, which is excellent and definitely accurate enough for me.

[Anonymous No.1264843]

Simulated result for >>1264842

[Anonymous No.1264870]

>>1264843
That's what I'd call flat: dynamic resistance ∆U/∆I=18V/32µA=562.5kΩ
You only need the leftmost transistor (Q8), rest runs in slave mode
I used the 'base rail' drawing convention, all connected

[Anonymous No.1264878]

>>1264831
because there's some inputs and calculations running beforehand for which I'd rather use the arduino than combine logic gates. Downside: The already limited arduino space is limited further.

The Idea was to get a 1$ walkman and control the input buttons by wiring them to the arduino digital pins. it'll look messy but the project isn't supposed to look good.

[Anonymous No.1264880]

>>1264806
>You could store the sample in processor's program flash and output it via PWM. You can store some seconds of sound that way, but playback quality is pretty low.
Yeah, but desu that's not long enough and also too little quality. Also about half the flash is used by a program beforehand already.

Nuvoton sound nice, but costs more so I'll have to pass.

[Anonymous No.1264881]

>>1264878
There's also a version that can directly drive a speaker. Buttons seem to be pull down.

[Anonymous No.1264894]

>>1264881
Yeah, I've seen that. The TF Card in my original Post includes a amp as well, so really I think they are very similar. Pros of the TF in my eyes were that the buttons are not already on it (one less thing to desolder) and that I didn't need another power source to drive it (it uses the arduino power).
Thanks for the help though, you guys saved my ass a few times already.

[Anonymous No.1264921]

I want to try making my own digital nightvision.
I have soldered a lot of stuff before but never really designed electronics.
Can someone walk me through things I need to know to design.
My main components would be a CCD camera and either and OLED display or digital viewfinder. I'm planning on using a CCD camera sensitive enough to not need an IR illuminator.
So the first step is look at the power requirements of my camera and display?
I'll need an on/off switch and maybe a gain adjustment. I'll need a driver chip for the display? How do I begin designing my board based on my camera and display selection? What do I need to look for?

[Anonymous No.1264925]

hello I'm trying to figure out this motor it's hooked up to 220V currently but it burned out

it has some capacitor etc on it
http://www.ebuy7.com/item/feeggdjhjhd

I found the exact one these pics are better than mine would be, attached is one of their pics

from what I can tell the ground goes directly to the motor
1 of the 110volts goes down a blue wire directly

the other 110 volt splits to a red which goes directly to a motor
and the other split goes to a capacitor then to a yellow that goes to a motor

is it possible to hook this to just 110volts?
the motor itself says 110V on it.

110V, 60Hz, 10watt, 3 uF / 500v capacit

is what ti says on the sticker on the motor

mode is
"YYHS-40"

[Anonymous No.1264926]

>>1264921

I'm actually researching the same thing

I'm finding halfway decent IR CCDs on aliexpress for the $15 range, looking at round (like used for watches) OLEDs for the $40 range.

[Anonymous No.1264929]

>>1264926
I will likely start cheap as well since I don't know a lot about electronics. I'm a machinist.
I bought the Carson Opmod DNV and took it apart to look at it, there is a lot of stuff going on in there.

[Anonymous No.1264931]

>>1264929

Would you know anything about making a housing out of aluminum that could be waterproofed with o-rings?

>i am looking into this so i can produce and sell a bottom tier but durable digital night vision red dot, and undercut ATN.

[Anonymous No.1264943]

I need a cheap crimping tool. I got one at dollar tree but it was shit and couldnt crimp. I can buy one from homedepot for like $10, but should I just get one of a different style from like china.

[Anonymous No.1264945]

>>1264925
>110V, 60Hz, 10watt, 3 uF / 500v
>220V currently but it burned out
no surprise
blue goes to one 110V
yellow+black to the other
leave red+black as it is

[Anonymous No.1264948]

>>1264945
the building it's in is
load
neutral
ground

the single load is 220V
the fan was purchased with the small building, from a different country. (this is all stock stuff)

blue goes to load 220V

yellow goes to capacitor

red goes to neutral & capacitor

idk I just tested it with my multimeter in the outlet and on the plugs

[Anonymous No.1264949]

about every other time I turn on my computer the fans sound like a fucking jet engine until I restart a couple times and I don't know what to do please help

[Anonymous No.1264952]

>>1264945
so it has 2 neutrals coming from the motor
one both go to the capacitor
only one leads out to the outlet's neutral

if it was a startup capacitor couldn't it just be in the load part? idk must not be the same as simple lights are..

the motor says 100V but the outlet is 220V and the plug is for that as well

[Anonymous No.1264960]

>>1264943
Different connectors require different crimping dies. The ones you get at the dollar store are meant for insulated crimp terminals such as in white goods and autos. If you're trying to crimp something more precise like Dupont terminals, a ratchet crimper for $15 on aliexpress is about the best deal going.

>>1264952
There's a reason it's burned. Can you guess?
You'll need a step down transformer or a motor designed for your local mains voltage.

>>1264949
>>>/g/

[Anonymous No.1264962]

>>1264960
no I don't need a step down you don't understand

the entire building was purchased from manufactuerers. the fan came with at that voltage and worked fine for years.

[Anonymous No.1264963]

>>1264931
Yeah I would know about making a housing. I'm also into guns and military equipment. I design gun ideas in CAD for fun.

[Anonymous No.1264966]

>>1264960
I don't get what makes something /g/ and what makes it /diy/

[Anonymous No.1264967]

>>1264962
>no I don't need a step down you don't understand
>>1264925
>the motor itself says 110V on it.
I don't understand either.
Why would a manufacturer label a motor as 110V if they expect you to apply 220V.
It's almost like they want you to burn it out.
Oh, wait. It did burn out. So it was a success.

[Anonymous No.1264969]

>>1264963

did we just become best competitors

[Anonymous No.1264970]

>>1264967
they made the building, the outlet, the fan, etc

[Anonymous No.1264971]

>>1264969
If you know anything about making electronics maybe we can work together?

[Anonymous No.1264973]

>>1264970

[Anonymous No.1264975]

>>1264971

I don't know much but I do know how to negotiate with chinese manufacturers

[Anonymous No.1264983]

>>1264970

[Anonymous No.1264986]

>>1264983
yea it says 220v on that one
there are 6 different versions of the motor

3 110v and 3 220v

[Anonymous No.1264988]

>>1264986
The point is, only two wires connect to the power.
(three if you count earth-ground to the case)

[Anonymous No.1264990]

>>1264988
only 1 of my wires goes to power
the other two go to neutral

[Anonymous No.1264996]

>>1264990

You're doing it wrong!

[Anonymous No.1264997]

>>1264996
I didn't do anything, for the 100th time
the creators of the shit, which it ran like that for a year.. did it

[Anonymous No.1264998]

>>1264997
MAYBE SOMEONE ELSE FUCKED WITH IT!

[Anonymous No.1264999]

>>1264998
the input is a ground, neutral, load

the motor has 4 wires

the neutral gets split between two of the wires

the load goes in as is
the ground goes in as is

I can read what the damn sticker thing says, and mine is even fucking 110V on the sticker, so idk why the chinese make a 220 version and don't use that in the product we bought long ass time ago.. but it just died yesterday
I've confirmed multiple times that the outlet neutral is the same one that splits

[Anonymous No.1265000]

>>1264926
Small displays are a pain to make a controller for, maybe look into using a cheap smartphone with VR goggles and connecting a camera to it through usb.

[Anonymous No.1265024]

>>1264966
Consumer electronics and PCs goes to /g/
Making stuff goes to /diy/
Making electronic stuff goes to /ohm/
lolduinos and fruitpis are about as far toward consumer electronics as /ohm/ goes.

>>1264997
>died after a year
Damn, those are some good motors

[Anonymous No.1265033]

>>1264996
My 220V/50Hz motor has 4 wires for two identical windings (same resistance). One winding has blue and red, the other has blue and white. The two blue wires go to N while red and white go to the terminals of the capacitor. When you connect the red side to L the motor turns right and when you connect the white side white to L it turns left. Exchanging N and L has no effect.

[Anonymous No.1265040]

>>1265024
Since when are Arduino tolerated here? I posted my robot arm last month and got mocked ceaselessly for not building a microcontroller for it out of pocket lint.

[Anonymous No.1265064]

>>1265040
>he doesn't know about semiconducting pocket lint
It's not a hard and fast rule. Signal processing using lolduino would be somewhat tolerated. Mechatronics and other hipster memes would better go elsewhere in /diy/

[Anonymous No.1265076]

Hey ohm, sorry if this is kind of spoonfeedy.

I have an FM transmitter because my car from 2007 has a tape deck and no aux port. The transmitter is solid, has been for years, but 2 issues.

1. The level from my phone is too low, esoecially compared to the radio. I need to amplify it. Any good stereo amplifier builds for trs to trs? I do a lot of guitar amp/effect repairs, mods and builds so I probably have everything besides the 3.5mm jack and plug on hand to build something. A gain or output volume control would be beneficial. I have several transistors, mosfets and opamps on stock. Some ICs as well. Not opposed to ordering anything.

2. Noise from a loop. If my phone is charging and playing through the transmitter. Static, erractic high frequency bleeps. I can't use some isolation transformer, but is there anything I can do to elimiante the noise? It's not noticeable at all if I'm listening to grind or modern hip hop, but anything with just a piano is completely destroyed by it. I was thinking about wiring some 18650 packs that charge when the car is off but when the car is on they isolate themselves. Open to anything, I only know how to get rid of ac ripple.

I can buy a new head unit with bt or an aux port, but I just like soldering. Money isn't an issue.

[Anonymous No.1265083]

>>1265024
I mean computer building is kind of making electronic stuff

[Anonymous No.1265087]

>>1265083
No, it isn't. Think of it this way, building something by soldering stuff onto a circuitboard is like a carpenter making a table. "Building a computer" is more like buying a table at IKEA and then being proud that you've been able to assemble it. Sure, you've done some work, but it isn't at all comparable.

[Anonymous No.1265180]

>>1265076
>Noise from a loop.
Does it go away when you charge the phone from a power bank? Amplifier is no problem but the input Z of the transmitter is needed. Some expect a low Z headphone output, others do not.

[Anonymous No.1265182]

Sorry for asking school related stuff, but does anybody have tips and tricks for VHDL?

A test is coming within a week, and I wish to prepare very well for it.

[Anonymous No.1265189]

>>1263731
>MOSFET gates are hi-Z
are you literally fucking retarded?

[Anonymous No.1265195]

>>1265076
What is the possibility that your phone/music player is driving the ground of the aux/headphone output to some virtual ground level above V-? That's not quite a ground loop but it can cause problems with levels and noise and even damage equipment. If I understand your problem correctly, you'll need to isolate either the power or the audio.
t.dealt with this 20 years ago

>>1265189
>are you literally fucking retarded?
Why, yes, yes I am.

[Anonymous No.1265337]

Maybe I'm just dumb but isn't that multiplexer with "not" gate on the input of A equivalent to (q xor sig_1)?

[Anonymous No.1265354]

>>1265189
mosfet gates might not be high z in practice but driving them directly off logic is sure as shit better than discharging a high frequency switch with a 10k resistor

[Anonymous No.1265536]

I was a retard and made my treadmill run too fast so it shut itself off mid run.

The flashing light on the circuit board indicates that the console is sending a signal greater than 0.0 mph so only DC is going to the motor.

The console doesnt light up at all but everything is getting a signal and there are no apparent burnt lines or broken solders. I saw some sights say check the fuses but there's no fuses.

Any clue?

[Anonymous No.1265558]

what

[Anonymous No.1265595]

>>1265536
if there's no fuse you just haven't found the fuse.

[Anonymous No.1265597]

I dunno if this is the place to ask, but I will.

Is it OK to set up two power strips on the same outlet (one on the top and one on the bottom) powering a computer, a few monitors, my scope, function generator, etc.

Will the circuit breaker of the house kill it if it draws too much, or could there be an issue?

[Anonymous No.1265598]

>>1265595
Will you look for me senpai

[Anonymous No.1265603]

>>1265597
you can check the maximum current rating of the power strips, it's usually marked on the bottom. That times your country's voltage (110V for fat burgers, 230V in the real world) gives you the maximum power the strip can handle.
As for the wall socket itself I'm not sure how you'd go about finding out the maximum allowable current. Perhaps there is a standard for house installations? Either way I'm pretty sure the strips would be the bottleneck

[Anonymous No.1265619]

Would you consider this a good layout for components?

[Anonymous No.1265644]

>>1265603
Your fusebox will go before your wall socket does. The maximum fuse you're allowed to use in a home in Europe is 16A, so that gives you 3700W of power before your fuses go.
You could of course buy fuses that won't trip until in the hundreds of amps, but it isn't strictly speaking legal. No idea what the case is in the USA, your wimpy 110V grid would give comparable total wattage at 33A, so maybe California and New York and any other states that give a fuck have 32A fuse limits?

[Anonymous No.1265652]

>>1265076
You might be able to just use a transformer full stop, something around 2:1 to 10:1 turns ratio, to amplify and isolate the phone's ground, provided the phone can drive enough current into it. If that is as stupid an idea as it sounds, any of the myriad of pocket preamp designs would work, even just a DIP-8 opamp running off 12V would do fine, assuming you need a preamp and not a full amplifier. Pretty sure you can buy audio isolation transformers in any case, not quite sure how else you'd isolate them, other than using an isolated flyback converter to charge your phone. That could be an interesting project if you're willing to dive down the PSU rabbit hole.

[Anonymous No.1265675]

>>1265619
kek

>>1265076
>>1265652
Isolated dc-dc converters can be had as a stock component.

[Anonymous No.1265685]

>>1265619
Hey mate, it's Gus, no idea who you are or if I'm in your class but you have the wrong footprints for those capacitors

[Anonymous No.1265687]

>>1265619
Haha no way, never expected to find somebody else here! I was in today's class at 4:00. Can't find the right footprints, do you know the codes for them?

[Anonymous No.1265692]

>>1265687
Nah, different class, and two of the caps are something like CAPR200 and a bunch of other numbers, the other is CAPR500 and a bunch of numbers

[Anonymous No.1265694]

>>1265692
Okay, cheers for the help. What course are you studying?

[Anonymous No.1265696]

>>1265694
EEE w/ industrial year. I'm tomorrow's 3-5 and then 7-9 in the labs.

[Anonymous No.1265700]

>>1265696
I'm Computer Network Engineering w/ placement, also in the 3-5 for Engineering Workshop. I'll be wearing a yellow- shirt so if you see me come and say hi

[Anonymous No.1265704]

>>1265700
Yeah man, I finished my board 3 weeks ago and I just come in to help my friends so I will

[Anonymous No.1265706]

>>1265619
>pic filename
It's impossible to say without knowing the design rules imposed by your pc board fab process, but unless you're using sharpie on single-sided copper, probably not. You should generally try to minimize trace length, which means keeping all the 555's timing components nearer the IC.

[Anonymous No.1265717]

It finally arrived from china. Holy fuck this DMM is small. I've never owned a DMM but I used my brother's Fluke a bunch of times and this one isn't even half the size of his Fluke. It looks like a toy.

Anyway, does anyone know where I can buy replacement fuses for this thing? I opened it up and fuses are tiny. Never seen a fuse this small. No idea which ones I should get...

[Anonymous No.1265720]

>>1265717
digikey has 5x15mm fuses.

[Anonymous No.1265723]

>>1265720
that's not the right size. no way those fuses are 15mm. also, any idea what type of fuse (fast / slow) and what amperage they should be?

I'm gonna get a set of quality ceramic ones but not sure which...

[Anonymous No.1265727]

>>1265723
i'd assume fast fuses on the low ranges because the sense resistors don't have a lot of thermal mass to them. the shunt may use a slow fuse. disregard my assumptions though because your manual should tell you. if it doesn't you should've just got the free meter from harbor freight.

[Anonymous No.1265729]

>be me
>soldering some Deans plugs on some banana plug LiPos
>manage to solder one battery into a short circuit
>terrifying fizzing sound
>some magic smoke escapes
>quickly break connection
>plug it into the charger to see if it still works
>3s cell now shows up as 2s, and immediately gives a "CONNECTION BREAK" error if I try to do anything, including a safe discharge cycle
Well, fuck. These batteries were expensive. Piece of advice for you lot, don't trust Chinese shrink wrap. One tiny touch from the soldering iron was enough to burn a rather large hole in the wrap on the lead I'd already finished.
>>1265717
I had one of those a while back. Don't trust it, mine was about 20% below the actual value when it measured voltage.

[Anonymous No.1265732]

>>1265729
>I had one of those a while back. Don't trust it, mine was about 20% below the actual value when it measured voltage.
wtf are you on about? it came out like 4 months ago and almost every review of it has been positive. Even that curmudgeon EEVblog Dave tested it. It's accurate as fuck.

[Anonymous No.1265737]

>>1265727
>>1265723
btw you should get some cheap digital calipers to measure things like this

[Anonymous No.1265762]

>>1265732
Sure, not with the exact same text on the top, but other than that it was identical.

[Anonymous No.1265813]

>>1265762
It's a standard housing, it's the second to bottom-line housing just above pic related.

[Anonymous No.1265896]

Under what condition will the input on the left cause the right transistor to open and let the cap empty its charge on the PTC?
I don't know the values of the components.
I don't know if the diode is normally shining or not.
All I know is that certain current or lack of it on the input is supposed to open the transistor on the right.

[Anonymous No.1265898]

>>1265896
The cap on the right is high voltage, around 350V.

[Anonymous No.1265916]

>>1265813
Fair enough. I just assumed it was chink shit, like the one I bought. Only cost five euros so I guess it's fair enough that it was shit.

[Anonymous No.1265918]

>>1265896
>Under what condition
under no reasonable condition
it's just another troll circuit

[Anonymous No.1265935]

>>1265896
That does not work at all, unless the phototransistor gets enough of a voltage across it that it turns on the normal transistor, which I doubt because I don't think they work that way.

[Anonymous No.1265939]

>>1265717
Did they fix the Ω range bug? Try to measure a 10 MΩ resistor.
>replacement fuses
3.6x10 mm, 200mA and 10A
The meter may soon be cheaper than a set of fuses..

[Anonymous No.1265945]

I'm starting an electronics club at my uni. Wish me luck boys

[Anonymous No.1265947]

>>1265945
Fuck, wish we had one, all my uni has is a Formula SAE engineering club, which isn't the janky homemade synths and shitty analogue fuckery I'm interested in.

[Anonymous No.1266071]

>>1262373

ravioli ravioli give me a rolleroni

[Anonymous No.1266088]

>>1266071
what would make it safe for school?

[Anonymous No.1266199]

>>1265685
>>1265687
>>1265692
>>1265694
>>1265696
>>1265700
>>1265704
You guize get a room.

[Anonymous No.1266206]

>>1265896
You sure you've got the right transistor there? PNP with emitter on top could work to discharge the cap when the LED is on, the arrangement you have there wouldn't do much.

[Anonymous No.1266506]

I bought this little adapter board. Soldering went okay but there was some flux residue I wanted to get rid of so I cleaned it with isopropyl alcohol, 70%. After letting it air dry there's all this weird white residue all over the board. What is this and what should I do about it?

[Anonymous No.1266520]

>>1265947
then make your own club, famalamalam

[Anonymous No.1266525]

>>1261407
I am trying to send serial data to my arduino using pyserial, but everytime I send something the arduino crashes. but when I send the same data over the serial monitor, the arduino does what it is supposed to do.

[Anonymous No.1266537]

>>1265916
Good thing to keep in mind is they'll never give you more than you pay for.

[Anonymous No.1266539]

>>1266525
python, not even once.

[Anonymous No.1266547]

>>1266525
opening the tarduino's serial port causes the usb controller on the board to send a reset signal to the microcontroller.
it interprets the DTR com port (rs232) signal as a reset.
google "arduino auto reset"
this is why every time you run your python program it crashes.

[Anonymous No.1266549]

>>1266547
* """crashes""" i mean. it's not crashing, the tard is designed to reset that way

[Anonymous No.1266550]

>>1266547
tnx, I guess I'll just add a delay after opening the serial port.

[Anonymous No.1266563]

>>1266506
You didn't clean it well enough, or your watered down alcohol didn't do its job. Try again and use brush, too.

[Anonymous No.1266564]

>>1266550
Or open the serial port so that the DTR line won't get toggled.

[Anonymous No.1266566]

>>1266563
I managed to clean it up. More alcohol and scrubbing with a toothbrush helped a bit but it took tap water to get most of it off, would've preferred distilled but none on hand. Afterwords I dried it with a hairdryer and reflowed a bit of solder the connections to clean them up a bit.

I think it was a no-clean flux in the solder and I shouldn't have put alcohol on it in the first place. There was some reaction that left that white crud.

[Anonymous No.1266600]

>>1266566
Did you mix leaded and lead-free solder?

[Anonymous No.1266639]

I'm looking into generating /synthesizing sound, without using any kind of samples or lut, and how to accomplish that. Any of you happen to know a good source to read up on that?

[Anonymous No.1266641]

>>1266639
I plan on using those sounds for music, btw.
And a technique I'm currently looking into is shaping and generating noise, but so far the results were... Less than stellar

[Anonymous No.1266654]

>>1266639
So... Analog synth shit?
http://musicfromouterspace.com/ is a pretty well known resource.

>so far the results were... Less than stellar
What does this mean? Results were bleep bloop? That's normal.

[Anonymous No.1266656]

>>1266639
I have some autism synth chips lying around. If I have a few extras I might be able to send you one or two. I'll look when I get home this evening and reply to this and your post if I gots any.

I dont remember what the chip is atm so don't ask. It's some chip that's probably straight outta the 90's.

[Anonymous No.1266658]

>>1266654
Bookmarked. Thank you kind anon.

I tried to shape a white noise, but the noise was not particularly white. Madebme realize how little o know of this topic.

[Anonymous No.1266712]

>>1266537
I don't know about that. Genuine Arduinos cost at least 20€, usually more, but I've been using Chinese ones for a tenth of that price for several years and haven't had any quality issues with them. Several have died, but that's because I've stupidly shortcircuited them, or pumped 24V into a 5V digital pin, stuff like that, never a problem that I didn't cause.

[Anonymous No.1266748]

>>1266712
I mean in the context of other chink shit. For instance, if you saw some 25 cent arduino ripoffs, would you believe they work anything like the $2 ones? There's a level where the stuff is adequate and works, and then there's the level 80% below that where the shit doesn't even work right, in the case of the $5 multimeter anon had, versus the $25 aneng which by most accounts is adequate as long as you're not doing HV stuff.

[Anonymous No.1266751]

>>1266656
>he has autism synth chips laying around
you could have made some bank with these a few years back, m8, but now a few of them have been reissued.

>>1266537
"sell on price, live on rice"

>>1266600
not that poster, but I do use one tip for both, could that be the cause of white crud on no-clean flux post-IPA?

[Anonymous No.1266780]

>>1266600
I am the og poster and no its regular 63/37 tin lead.

I think the core type was listed as 3C or Crystal 400 but I'm not sure what that means.

[Anonymous No.1266801]

>>1266639
>>1266656
these are the chips i was talking about. turns out i only have 1 of each of them. sry m8

>>1266751
these worth anything?

[Anonymous No.1266803]

>>1266801
1358 might be good for a ring modulator (used in the ARP Avatar iirc)
76477 are pretty easy to find and not all that exciting by themselves, need DACs or pots/switches to drive it
that speech synth chipset is a rarity, could fetch maybe $25 on fleabay

[Anonymous No.1266844]

Where can i buy a "tiny SMD fusible resistor"?

[Anonymous No.1266847]

>>1266844
um, digikey?
https://www.digikey.com/products/en/resistors/chip-resistor-surface-mount/52?k=fusible%20resistor

[Anonymous No.1266868]

>>1266844
Break your synthesizer?

[Anonymous No.1266870]

What u should really do is start following YVNG._.Burberry

[Anonymous No.1266897]

What did Forrest M. Mims III™ mean by this?

[Anonymous No.1266911]

I need a circuit that uses one switch to activate model rocket igniters in sequence

i have no idea what kind of thing i should type into google

[Anonymous No.1266912]

>>1266911
just use really, really long wires

[Anonymous No.1266914]

Where do you guys get cheap electrical wire. 18-22 gauge. No place in my city sells it.

[Anonymous No.1266920]

>>1266911
"sequential timer 555" seems like it'd be a fruitful search term

[Anonymous No.1266928]

>>1266920
seems a bit complex considering that i don't have to worry about looping through the sequence, once the igniter fires it behaves as an open switch couldn't i just be creative with the wiring?

[Anonymous No.1266931]

>>1266911
If you mean for each time you press a button you trigger the next motor (instead of >>1266920 triggering each motor after a delay after a single button is pressed) then use a shift register like pic related. Or use relays, I guess.

You'd better be making some sort of keyboard-controlled multi-stage rocket with KSP controls.

>>1266920
Couldn't you just use a few RC circuits with a single hex Schmitt inverter IC instead of a bunch of 555s or 556s?

[Anonymous No.1266939]

>>1266931
>shift register
seems more like what I'm looking for

is there clock-less 1-Nth setup that i could daisy chain together?

[Anonymous No.1266946]

>>1266939
Well you could daisy chain a few D flipflops together, but they come in DIP14 ICs anyway, so you'll actually just be wasting pin space and wire. The clock input is for the button pulse to go to, no oscillator required.

Just to confirm, you do want a single button to activate the next motor each time it's pressed, right?

[Anonymous No.1266950]

>>1266914
chinkwire isn't bad

>>1266931
yeah you could. now that I know the timing is meant to be even, could also use a 74273 octal DFF (20-pin package), use the master clear as a safety inhibit, and just jumper each output to the next.

[Anonymous No.1266978]

>>1266868
yes!

[Anonymous No.1266981]

Picked up an Energy Concepts 30820B oscilloscope for cheap today, I'm trying to test it now. It takes BNC probes but I don't have any. I'd like to see if I can get a response out of it before I go and buy a pair, so I'm trying to give it a signal using alligator clips. I'm assuming the live part would be the outer barrel, but I'm not getting any response. Does there tend to be something special with the center pin on these?

[Anonymous No.1266985]

>>1266981
>I'm assuming the live part would be the outer barrel.

No. Outer barrel is ground. Inner section is signal. I've been too lazy to find a probe and jammed a wire in there a few times. Works OK if you don't mind looking at a noisy signal.

[Anonymous No.1266991]

>>1266639
Sine-wave oscillators: either using a rotation matrix or d^2x/dt^2=-w^2*x. But on a PC, you can just use sin(); the other techniques are more relevant for uCs or dedicated silicon.

Filtering square waves; this is the basis of the Clavioline and derivatives.

[Anonymous No.1267036]

>>1266981
Make your own probes

[Anonymous No.1267042]

>>1266981
Just get some BNC cables you'll need them eventually as most pieces of test equipment use them unless you're doing RF work then you'll usually see type N and SMA connectors.

And no the outer barrel is not live. Almost all instrument grade cables are shielded cables and as such the out sleeve is grounded. Signal goes on the center pin.

[Anonymous No.1267045]

Retarded question time:
I want to replace a mechanical push button on a chip with an arduino. The button works by grounding a pin.
Can I use a digital pin, give a "high" signal to the pin and "LOW" to simulate a button press? Or do I need to use transistors?
(I'd run a dfplayer mini at 5V and the digital pins at 5V high. )

[Anonymous No.1267050]

>>1267045
Maybe, but if you play with AVR's pin direction register, you can achieve the open/grounded action too.

[Anonymous No.1267051]

>>1267045
>button on a chip
Never seen such a chip. Of course you can use any pull-down method you want, including a digital port or a transistor. The question is what initiates the button pushing. If you want to yell *PUSH* you need a microphone and some electronics, but it'll work.

[Anonymous No.1267053]

>>1267051
Now I'm retarded but not that retarded(or so I hope). I meant a normal push button is connected to a pin and ground. Essentially it grounds the pin when actuated. I want to automate that via digital means, so I can tell the arduino to set pin x to high and it simulates a button press

[Anonymous No.1267071]

>>1267053
I think the DFplayer has built-in pull-up resistors, so you need _not_ supply a HIGH signal, only LOW to activate the function you want. I guess it will not damage anything if you do though. A typical pull-down button is like an open collector or open drain output which means you only sink and never source current. Be aware that the duration of 'pushing the button' is evaluated. Short means 'next', long means 'volume up' or 'prev' and 'vol down', see pic.

[Anonymous No.1267079]

Can anyone point me to a moderately priced hot air reflow station. I just got chinked by the most recent $80 one I bought.

[Anonymous No.1267087]

>>1267071
Yeah, LOW would equal as ground, so it counts as an actuation, but when I do not actuate the button do I send HIGH as idle state or do I disable the digital pin? If so by setting it as non output?

[Anonymous No.1267109]

>>1267087
I would keep HIGH as idle state and use a diode.

[Anonymous No.1267168]

>>1267109
Okay, thanks!

[Anonymous No.1267272]

>>1266946
>single button to activate the next motor each time it's pressed
ideally, but simplicity is foremost, if i can delay the launching of the next in sequence long enough to get 1 launch per button tap that'd be good enough.

[Anonymous No.1267315]

>>1267272
Then a shift register is exactly what you want. How many stages/button pushes?

[Anonymous No.1267378]

>>1267079
>moderately
>the most recent one I bought
More details. Where are you? What station did you just get chinked by? What are the limits of "moderate"?
About to order the Aoyue 888a from SRA, myself. It also includes a pencil iron.

[Anonymous No.1267379]

>>1267315
6 possibly 7 depending on how it all comes together

[Anonymous No.1267405]

>>1267079
get an npt threaded cartridge heater, some fittings, a hose, and an air pump :^)

[Anonymous No.1267458]

>>1267379
sheeeeiiiit, I was worried you'd need like 30
a single CD4017 counter/decoder, some switch debounce circuitry, and igniter drivers would be enough for up to 9, and also would run fine off a single 12V supply.
(only one driver shown for clarity, duplicate as required)
(circuit completely untested but should work)

[Anonymous No.1267483]

NEW THREAD

>>1267468
>>1267468
>>1267468

NEW THREAD

[Anonymous No.1267506]

>>1267458
thanks

[Anonymous No.1267509]

>>1267506
addendum: Vgs(on) should be > 4V not 5V

[Anonymous No.1267953]

>>1262373
Roll

[Anonymous No.1267954]

>>1267953
Re-roll

[Anonymous No.1268026]

>>1262373
rollan