Electrical Engineering V3

[Chryseus]

I keep forgetting how to bias jfets properly so I made a tutorial.

[img]http://i.imgur.com/vWoXGEu.png[/img]

[nikomo]

[img]https://i.imgur.com/1mD9hVD.png[/img]

Now the real waiting begins.

[Staneh]

My parts arrived today, drilled some holes in the enclosure and it looks like this right now

[img]http://puu.sh/h7hVY/bbac258c09.jpg[/img]

I'm going to spraypaint it orange first, then assemble everything and do all the electrical stuff, but it's been a good day.

[RoflKawpter]

Hey guys, amateur here.

Just out of curiosity, a friends girlfriend dropped an x360 usb controller and now it wont work. The leds in it flash quickly sometimes, they stay solid other times, etc.

Looking at the controller, I see this.

[img]http://i.imgur.com/HxO159Q.jpg[/img]

Exploded quartz timer? Broken ic? Just a shit ton of flux?

I cant open it till I get home but this looks to be a glaring issue.

[Chryseus]

Looks like a blob of epoxy over an IC, The most likely cause of the problem is either bad cable or cold solder joint.

[Cakebatyr]

There also appears to be brown gunk on the inside of the plastic case above the epoxy.

[shodan]

[QUOTE=Cakebatyr;47490275]There also appears to be brown gunk on the inside of the plastic case above the epoxy.[/QUOTE]

Maybe somone held a lighter under it or something
Quarts timers don't just randomly blow up

[Chryseus]

The assembly man in China forgot to wipe.

[nikomo]

The assembler in China wasn't instructed to wipe, because it would slow down the process, end users don't look inside products, and it doesn't affect functionality.

[Lily]

The soldier joints on that cap near the bottom right look questionable.

[pentium]

Anyone here willing to give half an hour to an hour of their time to write some simple arduino code? I totally fail in the programming department.

[nikomo]

[QUOTE=pentium;47493418]Anyone here willing to give half an hour to an hour of their time to write some simple arduino code? I totally fail in the programming department.[/QUOTE]

What do you want? I can give it a shot.

[Chryseus]

Rigol are increasing the recommended retail price of all their equipment by an average of 13.4%, so if you want something best to get it right now.
Here is a price comparison from Batronix: [url]http://www.batronix.com/pdf/Priceadjustment_Rigol.pdf[/url]

[nikomo]

Buy gear from a competitor instead and tell them to eat shit.

[woidoi]

any reason behind the price increase besides profits?

[r0b0tsquid]

[QUOTE=scratch (nl);47495999]any reason behind the price increase besides profits?[/QUOTE]

Trying to raise their image beyond "budget brand"? It's silly but look at Volkswagen these days.

[LoneWolf_Recon]

Me an my Uni's team are at the IEEE hardware competition currently refining our robot before the rounds start, and I've setup my workbench awaiting repair tickets... :v:

[img_thumb]http://oi57.tinypic.com/k50hz6.jpg[/img_thumb]

[pentium]

[QUOTE=nikomo;47493952]What do you want? I can give it a shot.[/QUOTE]

Product: Arduino Pro Mini
Purpose: Generate short ASCII strings when digital inputs are triggered

Inputs:
-Digital 2 (Dialing Control) (0V LOW/+5v HIGH)
-Digital 3 (AA Control) (0V LOW/+5v HIGH)
-Digital 4 (AA Register Feedback) (0V LOW/+5v HIGH)

Outputs:
-TxD/TxO (TTL RS-232, 300 baud)

When Input 2 goes high, the microcontroller outputs [b]ATD[/b].
When Input 3 goes high, it first checks the status of Input 4. If low the microcontroller outputs [b]ATS0=1[/b], else it outputs [b]ATS0=0[/b].

In both cases, the microcontroller only outputs the string ONCE per state change. That is, if you hold the specific command button down the microcontroller does not spam the command over and over. You have to depress and press it again transmit it again.

[nikomo]

Try this out.

//interrupt 0 = D2
//interrupt 1 = D3

void setup(){
  //Setup inputs
  pinMode(2, INPUT);
  pinMode(3, INPUT);
  pinMode(4, INPUT);
  
  //300 baud serial
  Serial.begin(300);
  
  attachInterrupt(0, dialControlInterrupt, RISING);
  attachInterrupt(1, AAControlInterrupt, RISING);
}

void loop(){
}

void dialControlInterrupt(){
  Serial.print("ATD");
}

void AAControlInterrupt(){
  if(digitalRead(4) == LOW){
    Serial.print("ATS0=1");
  } else {
    Serial.print("ATS0=0");  
  }
}

That doesn't send a carriage return or newline, by the way.
If you swap the Serial.print to Serial.println, it will send a carriage return and then newline.

[Staneh]

Okay so I'm making this guitar pedal, it all works but I have one last problem, I have a 2.1mm DC jack which I put in a 9V adapter, but when I hook up the wiring it doesn't send power through, if I disconnect the wires and test it it returns me 9V, any help here?

[Chryseus]

There is a short somewhere ?
You got the polarity wrong ?

[Staneh]

I tested it with a battery and it worked fine, that's the weird part.

I am using this power jack:

[img]http://www.taydaelectronics.com/media/catalog/product/cache/1/image/211x211/9df78eab33525d08d6e5fb8d27136e95/a/-/a-844.jpg[/img]

There are 3 connections:

[img]https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcSQX_Cg-ZtTEUJ7XXi8U37wSjlYi2QpCi18cpYn82LNuo_Gspg-eQ[/img]

Could anyone identify all the connections for me, so I'm sure that I'm hooking it up right? Because I'm not sure now.

[gamerpaddy]

[IMG]http://i.gyazo.com/06e9a55483ebd2f03efc8a6060055998.png[/IMG]
dont you have a multimeter? just to get 100% sure.

[Staneh]

I have it hooked up like that right now, but still doesn't work :( Battery still works, don't have a multimeter

[Ddrl46]

[QUOTE=Staneh;47512423]I have it hooked up like that right now, but still doesn't work :( Battery still works, don't have a multimeter[/QUOTE]

Can you take a picture of the label on the adapter, for all we know it supplies AC instead of DC.

[Zero-Point]

Or possibly not enough current (doubtful, but a possibility).

[Staneh]

Nevermind, I found out it was the guitar pedal enclosure messing with the current, if I took the jack out of the enclosure it worked just fine, so I isolated the jack from the enclosure and it worked just fine! Thank you guys, my guitar pedal is now complete <3

[r0b0tsquid]

Did you short the jack through a metal enclosure somehow?

[pentium]

[QUOTE=nikomo;47496828]Try this out.
-code-[/QUOTE]

Thanks for the code Nikomo. I'll give it a try once I figure out my intermediate nightmare. I can't fucking get any of my Pro Minis to upload. :suicide:
They compile and then try to communicate and fail with what are apparently standard communications issues (check cabling, check cabling, check adapter, check cabling....)
After blowing one MAX232 somehow in the process I decided to build a breadboard plugin to narrow down the probable fault locations.

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8922.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8923.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8919.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/max-232-arduino-lg.png[/IMG]

It looks great. It should by all means work but it's so weird. I've never run into interference like this before. I can send characters at a low baud rate to the adapter with any terminal emulation application and it will echo them back. Thing is, there is nothing being relayed back to the computer from the arduino. TTL TxD remains silent. It's bouncing back through the MAX232. Even more baffling is that the RS-232 signalled TxD line will antennuate on just about anything. I can be spinning in my chair and the terminal emulator will spew out garbage characters. I've never seen EMi this bad.
Of course, you unplug the Arduino and everything functions fine, even with a physical loopback connecting TTL RxD and TxD at the socket...which makes no sense as it wasn't the source of any of the problems.
I'll have to order one of those newfangled USB adapter. Woo, wait times!

[editline]The jews did 9/11[/editline]

Also repaired another piece of equipment from that pickup. This time it was the video generator. Lets you produce just about any type of video signal up to 1920x1080 but it was driven by a 486 machine whose battery had leaked and caused all sorts of madness. It wouldn't even POST before it was cleaned.

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8877.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8882.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8885.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8897.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8902.jpg[/IMG]
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/IMG_8910.jpg[/IMG]

[nikomo]

My cheapie Uno clone refuses to program if there's anything non-trivial in the UART RX port.
A MAX232 is definitely enough to mess with me, I had to keep removing my little shield thing that was using that, when I wanted to program the Arduino through UART.
Remove the Mini from the socket and then try to program it.