Is the Arduino made to be idiot proof, or am I just getting lucky?

Hello,

since getting my Arduino about a week ago, I've absolutely brutalized the thing. Just now, I stuck a 12v AC power supply through the VIN pin thinking it was DC. I heard some crackling, surely thinking I fired the little guy. Nope, still works. I've also plugged 9V into the 5V pin, accidentally shorted it multiple times, and plugged in 24V through its DC jack.

Is there some type of protection in place to save it from newbies like me? If so, what does it do exactly? What are the chances that something is actually friend, and I'm not noticing? Is doing the above even "that bad" if the little guy is still working?

toxicxarrow:
Is there some type of protection in place to save it from newbies like me?

No.

What are the chances that something is actually friend, and I'm not noticing?

100%.

Is doing the above even "that bad" if the little guy is still working?

One point of an Arduino is to learn. You've learned. Mission accomplished.

Get another ordered soon and try to be more careful.

@Coding Badly Yea, looks like you're right. The lights work and all, but it doesn't connect to my PC anymore after hooking up the AC power supply. No port visible in the IDE, either.

What are the chances I could order another ATMEGA chip and replace that? Is there a way to identify what exactly I fried?

Been there, done that, remixed, and repeated. lol. this is why I love the clones from china. pro-mini's are like $2, so when one goes :pffft: I don't have to pull my hair out, its just a "whoops! I guess I'll try to not do that again!"

I'm guessing you have an Uno...? I got my first Uno from my parents for Christmas one year, and I managed to not destroy it for half a decade before accidentally running 12V into the 3.3V pin, killing it very quickly, and very effectively. I have a sentimental attachment to it, and after doing a little digging, I determined the chip that lets it communicate through USB is likely fried, and contains hidden pads, making it extremely difficult to replace. So there are many things that can get fried other than the Atmega chip itself.

I decided I'm going to just frame my original Uno as a memento.

@silly_cone Thanks, I feel a little better about now. :slight_smile:

Thinking about it, an AC power supply into the barrel jack shouldn't work, but I am surprised it trashed the board, since there's that diode in series with the power to prevent reverse polarity from doing damage.

Doesn’t VIN bypass that diode (as shown here)?

Note that OP said it was when they attached 12V AC through VIN that it crackled, not when they plugged 24V AC through the barrel. The barrel does look it goes through a diode prior to the 5V regulator, but the VIN goes straight to the regulator.

I am proof that it is not idiot proof! :wink:

If I have to order a replacement for something I fry, I get at least 2. If I found one way to let the smoke out, it is likely that I will find another way.

And with the silly-low cost of the clones, I sometimes just order 10.

Oh - yeah if it was straight to VIn, that’d do it. That’s why you should use the barrel jack, especially as a newbie.

AC on the DC socket won’t harm it because of the polarity protection diode, but 12volt AC could be close to 20volt DC peaks on V-in.
It could survive 24volt in the DC socket, but the caps are probably 16volt, so “cracle/pop” after some seconds.
9volt on the 5volt pin is probably the worst you could do.

Don’t try to fix this with a new micro. The USB<>Serial chip is most likely also fried.
Seems you’re not ready yet for a real Arduino. Get some $5 clones to do your mortal experiments with.
Leo…

Is there a way to identify what exactly I fried?

Sometimes the chip will get hot when powered-up.

With the microcontroller, sometimes you can check to see if the clock is running (with an oscilloscope). If it's not, the chip is probably fried. (It's possible to have a partially-bad microcontroller, but usually the whole chip dies.)

If you have an UNO board with the plug-in chip it's certainly worth trying another one. Worst case, it doesn't help and you've got an extra chip. Make sure to buy an "Arduino" chip with the bootloader pre-loaded! A "blank" Atmega chip is useless unless you have a way to program it.

Of course you can check the voltages. If 5V and/or 3.3V are low, it could be a bad/blown regulator chip, or it could be a shorted chip "dragging down" the voltage.

If you have a stand-alone programmer you can try programming the chip. The bootloader isn't much help because there are several things that can make that fail, but if the bootloader works, the chip is OK.

If you over-voltage or reverse-voltage a board, of course there is a possibility of burning-up more than one chip.

The thing about troubleshooting/debugging is... You NEVER know for-sure what the problem is (was) 'till it's fixed. And, SOMETIMES after it's fixed you don't know what the problem was!

Is the Arduino made to be idiot proof, or am I just getting lucky?

I had a shorted output pin once, and it was shorted for at least several minutes, or maybe an hour... Long enough for me to troubleshoot it, and panic when I discovered the short! But, it survived with no problems.

I had another Arduino die "for no reason" (probably static discharge). I usually ground myself before touching electronics but at home I don't have a ground strap. It an SMT version and I didn't attempt to repair it.

I've never over-voltage'd an Arduino or ATmega chip. But at work, we have a 5V board that I've over-voltage'd a few times.... If I apply 12V the RAM chip will die every time. Sometimes the CPU survives and sometimes not. Sometimes another chip will burn-up too. But, my adjustable "5V" bench power supply only goes to about 7V and I've never hurt a board at 7V, so I'm safe as long as I'm using that power supply.

AC on Vin will have trashed so many parts that you should just place the board in the trashcan and buy a new one.

If it's an official board, you've definitely trashed the 16u2 (the chips on the clones aren't quite as fragile - but AC on Vin is sufficiently severe abuse that you'd probably trash that too) - and you've also almost certainly trashed the opamp that does the power supply switching and buffering of pin13 LED, the regulator, possibly the electrolytic caps, likely the '328p.... There ain't much left on the board that you haven't likely destroyed.

Reverse polarity (including AC) from something capable of outputting more than an mA or so is about the worst thing you can do to an Arduino...

toxicxarrow:
What are the chances I could order another ATMEGA chip and replace that?

With those symptoms, zero. The processor responsible for USB-to-serial conversion is troubled. You may be able to reflash it to add some life to the board.

Is there a way to identify what exactly I fried?

You are likely to endure pain from things that are not outright fried but damaged so as to appear to be functional.

Thank you for all the replies; I learned a lot. I'm almost glad I fried it, just for the learning experience. I'm still addicted to the whole Arduino thing; definitely going to need a couple spare ones for future destruction projects.

The processor chip is quite robust against reverse polarity. I got the polarity wrong on a stand alone Arduino like circuit powering it from a bench supply, that was current limited to 1A.
It survived long enough for me to find the problem and it still works.

Attiny85's also seem exceptionally robust to this kind of thing. I've given them reverse-polarity more than I'd care to admit, and up to 12V on the VCC pin to where the chip got HOT, and I've only successfully destroyed 2 or 3.

You really gotta test those second-hand-store power-supplies with a voltmeter- you can't trust the markings on the wires, especially after you chop off the plug that used to be there. :confused:

I have had my atmegachip placed the wrong way around and put power on the uno. When I finally found out why it wouldn't do anything I was sure it was fried. It wasn't xD

toxicxarrow:
Thank you for all the replies; I learned a lot. I'm almost glad I fried it, just for the learning experience. I'm still addicted to the whole Arduino thing; definitely going to need a couple spare ones for future destruction projects.

Interesting point - you haven't explained whether it was a real UNO or a clone UNO or a fake UNO without the 16U2 USB interface chip. Fakes with a CH340 aren't actually UNOs at all, but a variant of the earlier Duemilanove. :astonished:

Point is of course, if it was other than an expensive actual UNO, you have lost nowhere near as much money. :grinning: