/diy/ - Do It Yourself

>>1034261
>The dispatch recieves a call and types an adress to a computer. The driver recieves adress to an android smartphone. Both gadgets have an internet connection but are not connected to the same network.
>Is it possible to code a program like that or do I need a server?
>Thank you in advance for any information!
There is two ways to do this:
1. either both phones would need to have a fixed IP address (each phone has its own fixed IP address) and each would need to know the other's fixed IP address, or-
2. you would need a web server with a fixed IP address, that both phones would know connect to.

#2 is way more practical than #1.
Assuming you use #2, then-
3. each phone has the ability to send a request to the server (that contains the data to send) and
4. each phone on the system has their own web page, that they automatically refresh at a certain time interval--say every 30 seconds or so. Any new info for the phone is contained in the page.

The way a normal web browser works, it can only "ask" the server for info first--the server has no way of "telling" it anything without being asked.
Writing a web page that automatically refreshes every 30 or 60 seconds (or whatever time interval) is a easy way to let the server initiate data transfers.

If you want the server to have a way to initiate data transmissions, there is a thing called push notifications but it is more complicated to use and all web browsers do not support it the same way.
https://developers.google.com/web/updates/2015/03/push-notifications-on-the-open-web?hl=en

Also I would agree with others who have said: there is already websites offering services for bouncing web data between cell phones. Maintaining a web server is not a part-time job, what with hackers and all....

>>1022416
>I currently have a $20 extech I've had for like 4 years and while it's been a god damn champ I just wanted to get something fancier with more features without spending fluke money (aka a car payment).
If you just want something fancier, then the key question here is "what does this meter do that the Extech doesn't?"
I got a HoldPeak 770D for that reason. 5 digits, 40,000-count, NCV, jack shutters. $60 on Amazon or aliexpress.

>With my ex tech I can put the leads wherever I want and flip the dial and I've never had anything pop even when i accidentally measured a wall socket voltage in DC mode the other day. ...
A wall socket isn't really 'high voltage', and the usual problem is the [amps] setting.

If you search google for "osha accident report detail multimeter" it will find a bunch of reports involving multimeters.
Reports where a multimeter exploded usually fall into two categories:
1. a multimeter was connected to a voltage way higher than it's rating (such a 600 or 1000v-rated meter accidentally connected to a 5000v source)
2. a multimeter with the leads connected to a live power source, and the knob was moved to--or through--the "amps" setting.

Multimeter companies can't really do much about type-1 accidents, and even Fluke meters explode in these circumstances. Some OSHA reports give the meter brand and model name, and there's Flukes in there.

Multimeter companies do a few things to try and avoid #2 from happening.
A lot of them use a knob that only turns part-way around, and arrange the amps settings separate from the other settings (many companies do this).
Some meters beep if the cables are connected wrong (Fluke), some meter jacks light up (Mastech), some meters have an LCD that shows what jacks you should use (Uni-T) but these don't STOP you from doing it wrong. Only jack shutters actually prevent this from happening.

>>955232
>I'm a noob when it comes to programming and I'm trying to write a Java program to fetch data from an Arduino and plot it on PC.
I dunno how to do it on Java, right off. I tend to write stuff on Windows in VB myself.
but anyway,,,,,,,

1. To get the data from the USB port, what you want to do is called "reading from a COM port". there is pages out there showing how to do that

2. How to make a GUI,,,,,,,,, I don't know what Java IDE you are using. Many of the free ones don't include a GUI designer at all (I don't know about you, but my life is too fucking short to design GUIs in a text editor). So you may need to go download a free Java GUI designer for whatever IDE you are using--Jcreator, Netbeans, Eclipse or whatever.

~~~~~~~

I don't use Java much, the only thing now is writing Android apps cause that's all that Android Studio does.
I don't know about now, but ~10 years ago when I was coding more, Java never lived up to its claim of being transportable. "Write once, run anywhere" was a nice idea but if your program had anything more than plain IDE stuff and simple file reading/writing, there were issues that came up on 'other' platforms.
It might be different now but I prefer MS Visual Studio (that is very good, and very free).

And everybody important uses Windows anyway :D

>>888428
>everything might be fake
But both components did work... The original was just a less-than-ideal choice in this instance.

Anyway--most China fakes and salvage is VLSI chips that are expensive to buy new. I've bought lots of basic components off aliexpress and not had issues with any them not working as intended. Many of these retail for only a few cents each. The IRF520 and IRLZ34 mosfets both only sell for about fifty cents.

Higher up the price scale, so far all the couple dozen arduino copies I've bought worked 100%.... All the TFT screens I've bought worked 100%.... A bunch of stepper and BLDC motor drivers and rotary encoders all worked 100%...

What kinds of fakes do you suspect exist?
I have heard of two in particular:
1--the Sparkfun arduino chip fakes, that were totally non-functional ( I test the boards when I get them, I load a different 'blink' sketch and see if they run it properly )
2--the FTDI chip fakes,,,, but I never saw any message on the PC that any of the arduino boards I had did anything wrong. And the FTDI thing was relatively huge.......

From my perspective the danger of buying incorrect parts seems to be larger than the danger of buying counterfeit parts. How much should I worry about having a problem that I don't have?

>>878255
>How would you invent a clock?
that's virtually empossible, it takes like thirty ardweenos (you havent got the sand-jiggawatts)

>>859027
>there, i fixed it. you're so particular. why do you care if it gently wakes you up?
because YOLO

>>859028
>get pi instead. many projects.
yea, like,,,, a home server.
Or a MAME cabinet.
Or... or.... a... ummmm,,,, ? (I'm sure there must be something else, but those are prolly 98% of what I hear about...)

>>835935
>Explain to me? Why cant I run Linux on a mATX board?
you could, but if you wanted Linux for something like this it would be easier to just use raspberry pi
>Why cant I run Windows7/8/10/HAL 9000 on a SBC? PS, There are embedded Windows OS.
yea but where can you buy an embedded windows install (that is not already got inline trojans in it)? certainly not file trading.
as I've seen it the embedded Windows installs are only sold to OEMs (and most embedded windows is still WinXP, that Ive seen).
And what are a Linux-type board/Windows-type boards. I didn't know there were boards out there that only support one type of os.
it's a matter of what is practical.
when you get Win7/8/10 running on a rpi be sure to let us all know. until then I'm just going to keep telling people that rpis "only run Linux"

>>767513
>Arduino is for normal people who have no background in electronics or coding, but need a controller, something this board continually forgets/refuses to acknowledge. It's much easier to just hang shit on it, amirite?
yes, you are right.
Arduino is for quick-building digitally-controlled stuff, and there's nothing wrong with that from a hobbyist standpoint.

>>769016
>... it also prevent people that wouldve been actually interested in actual electronics to really shine and develop a real knowledge base.
it prevents people from learning electronics? .....nigerian you crazy