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Topic: Arduino UNO smells funny when power is connected to it (Read 1 time) previous topic - next topic

dmoncz

Hey there, I registered an account to ask this, and possibly many more questions to come. This is my first 'true' experiment with electronics, aside from computer building, and a short lab I did last year in college.

I'm trying to build a simple robot, whose only function right now is to move forward. I have two servos (modified for continuous rotation, and such) connected to a plastic sheet with wheels attached to them. The servos were connected to the 5 and 9 pin, and I wrote a program that made them spin in a loop. I was ready to see the robot move portably, so on a breadboard, I added a 6V NiMH battery, and I connected the power wires from the servos. On the Arduino, I had wires going to the 9 and 5 pins, and wires coming from the 5V, and GND to the breadboard, hooked up to the correct polarity.

The thing started to smoke quickly, and feel warm, so I unplugged it quickly. I removed everything from the Arduino, waited a few minutes for it to cool down, and then plugged the USB cable into my computer. The Arduino didn't smoke, but it had a faint 'smoking' smell,  so once again, I unplugged it. I felt along the bottom, and the only places where it was warm were the two external power connections (USB and DC ones)

..What did I do wrong? I'm sorry if this question has been answered before, but I'm still pretty new to this, and I honestly don't know how to search for a problem like this. Other people talk about their 5V regulators being the hot parts, but mine is cool. It doesn't help that 'burning' has another meaning when we're talking about these things, haha.

Oh, also, I connected a LED to pin 13 and GND, and it stays lit,even when the board is heating up... I'm not sure if that information is useful, but there you go.

Msquare

The blue smoke MUST remain inside the Arduino at all times, else it fails ...  8)

If the Arduino chip got warm, warm enough to smoke, then you did not connect your battery or servos correctly.

WIth nothing but the USB port connect to your Arduino board you can try to upload and run the blink sketch. If it works you have been lucky.

Or did the smoke come from something else than the actual microprocessor chip?

Coding Badly

Oh, also, I connected a LED to pin 13 and GND, and it stays lit,even when the board is heating up...


With a resistor?

dmoncz

Whoa, you guys, I wasn't expecting replies so quickly, thank you.

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If the Arduino chip got warm, warm enough to smoke, then you did not connect your battery or servos correctly.

Fantastic, I must have gotten careless, because I was about to get the thing moving across my room finally.

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WIth nothing but the USB port connect to your Arduino board you can try to upload and run the blink sketch. If it works you have been lucky.

Uhhh, this might be bad, because when i try uploading the blink sketch, I get the avrdude: stk500_getsync(): not in sync: resp=0x00 error. Of course, I tried to be as quick as possible, so I might not have given the computer enough time to ..do... stuff.. I'll try another PC soon.

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Or did the smoke come from something else than the actual microprocessor chip?
Don't know. I saw and smelled smoke, and as a reaction I immediately unplugged the battery from it. It hasn't smoked since.

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With a resistor?


Yeah, sorry, I figured I talked too much already when I wrote that, so I glossed over some details. I think I'll just put up pictures instead of trying, and failing to describe the circuits properly.

Here, I'll try to get into the habit of posting pictures now: http://imgur.com/xVjNm

Coding Badly


The full question is "Did you include a series current-limiting resistor when you connected the LED?"  The answer, determined from the image, is "no".  That will damage the processor.  Don't do it again.

A very complete tutorial is available here... http://www.ladyada.net/learn/arduino/lesson3.html

dmoncz

Connecting it to another computer didn't help, so it looks this is permanently damaged. It can clearly draw power from a usb port, I wonder why it can't receive data.. =/

Can I get some use out of this board still? Or should I just toss it and get a new one?

(I've reread the next paragraph, and concluded it's a confusing mess of weak explanations for myself.... I'll keep it there because I've already wrote it, but beware)

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A very complete tutorial is available here... http://www.ladyada.net/learn/arduino/lesson3.html
Yeah, I used those tutorials when I was waiting for all my other parts to come in.I only read up to the third one though. When I made the circuit in my picture, I combined the concepts from the first tutorial (actually connecting a LED to the Arduino) and the third (attaching the resistor)... I guess I still have to learn how the Arduino connects to itself, because I thought connecting wires to pins on the Arduino is the same as on the breadboard (my mini-breadboard is really shoddy quality, I don't like connecting things into it.)

el_supremo

Why did you put an LED on Pin 13? There's already one there on the board.
Remove it.
What value is that resistor (colours in photo aren't clear) and what is it connected to? Get rid of it too.

Remove any other external stuff from the board and try to connect the bare board to a PC with only the USB cable. If you smell smoke again disconnect it and give up on that board. If not, try to load the blinking LED example sketch. That should blink the onboard LED. If you can get that far, you've still got a (mostly) functional UNO.

Pete

cr0sh

Is it me, or does the smaller Atmega (USB controller) look like what smoked?
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

MarkT

Without knowing precisely how you wired things up its only guesswork here.  When you say 6V NiMH I presume you mean a 4-cell NiMH battery (about 5.4V which is just in the safe zone for the Arduino).

You weren't connecting the servo supply direct to the +5V pin of the Arduino were you?  There is a risk of voltage spikes on a servo supply rail unless it's properly decoupled - servos contain motors, motor widings have inductance, inductors generate high voltage spikes if not tamed correctly.

It does sound like the USB interface chip got damaged, and the most likely reason is over-voltage on the +5V rail, but then I've little to go on.
[ I won't respond to messages, use the forum please ]

kd7eir


Is it me, or does the smaller Atmega (USB controller) look like what smoked?

Is it me, or does the smaller Atmega (USB controller) look like what smoked?


It looks the same way to me.

spcomputing



Connecting it to another computer didn't help, so it looks this is permanently damaged. It can clearly draw power from a usb port, I wonder why it can't receive data.. =/




Try opening a serial monitor and type anything into the input box and send it.  Watch the Rx led.  Does it blink?

I think you might have fed the battery back into the 5V pin with the USB connected.  The only thing you will want to feed back from the external circuit is the ground.  At 10V, you tripped the MCU fuses and the Atmega will either need to be reprogrammed or replaced (See if you can find another Atmega328P to swap out and test). 

Apparently, if you run 20V+ through the MCU the physical fuse trips (Cracks the ceramic package)!

As for your original project, you might want to use a half/full-bridge shield (http://www.adafruit.com/products/81 ).

Good luck.
http://www.spcomputing.com

ematson5897



Is it me, or does the smaller Atmega (USB controller) look like what smoked?

Is it me, or does the smaller Atmega (USB controller) look like what smoked?


It looks the same way to me.


It also looks like the chip below the crystal did some smoking too

smeezekitty

Since multiple things seem to have smoked, I would bet there is a good chance the OP applied reverse polarity.
Avoid throwing electronics out as you or someone else might need them for parts or use.
Solid state rectifiers are the only REAL rectifiers.
Resistors for LEDS!

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