I only get to work on my arduino every few weeks, so sometimes and get interrupted a lot by small children, so if I completely forget what is on the firmware, then I unplug the pins (because I haven't got anything soldered on there) should I be 100% certain I'm not going to fry my board?

  • There have been microcontrollers in the past that have functionality that allows you to create internals shorts or setup the clock in a way which means they are unrecoverable, but not recently Commented Feb 27, 2014 at 9:11

4 Answers 4


Although the controllers on an Arduino are pretty well protected, they can still be damaged by ESD (Electro Static Discharge). The same effect that makes a crispy sound when you pull off your woolen sweater in the winter, or after walking with rubber shoes on a carpet and you touch someone else or a metal and grounded object and you feel a pick. Static electricity can damage the controller. It may get completely broken, or it may function 'most of the time' or lifetime may be shortened.

An Arduino is also easily killed with an piezo gas lighter, just make the spark near the copper traces that feed directly in the controller. This is largely the same effect as above.

Again, the controllers themselves are pretty well protected, don't worry too much about them. But with kids running around (on their rubber shoes) better make sure they don't accidentally draw a spark from their little finger to your Arduino. The protective metallic bag is best, but putting it away in a cupboard or box should do the trick equally well.

As a general rule of thumb, the faster the electronics, the more sensitive it is for ESD. A Due is probably more sensitive than a UNO or a MEGA. But with normal, avoiding static electricity, use you should be OK.

  • An Arduino is also easily killed with an piezo gas lighter, just make the spark near the copper traces that feed directly in the controller This one is funny: why would someone want to do that? Is that a real-life experience of yours?
    – jfpoilpret
    Commented Feb 26, 2014 at 22:05
  • 1
    @jfpoilpret I don't know it is a fun experiment (for cheap chips that you don't need anyway). You never know with kids. But is was mostly to illustrate what is going on.
    – jippie
    Commented Feb 26, 2014 at 22:08

Arduinos are far from bulletproof but with nothing connected (apart from a power source of course) I doubt it will come to harm. If in doubt, upload Blink to it.

There are rugged Arduino-compatibles. One of them has a rather obvious name

  • 1
    What would that obvious name be? Ruggedduino? ;) You probably should put that in your answer because it could be called BulletProofDuino and that last sentence would still be applicable. Commented Feb 26, 2014 at 22:49
  • @AnnonomusPerson: I try to limit the amount of advertising I subject you folk to. (Especially(?) as I don't have any affiliation with the company concerned) Commented Feb 26, 2014 at 23:00
  • It seems though if a user wants one that you should tell them about it. You can just say I've heard of _____. Not to mention, you're not really affiliated with Arduino, either. :) Commented Feb 26, 2014 at 23:05
  • @AnnonomusPerson: Answer updated to be less coy. Commented Feb 26, 2014 at 23:09

It's generally a good idea not to try to take input from a pin configured as pinMode(OUTPUT) and vice versa. In addition, I prefer not to take input from tristated pins. Both of these cases are harmless, but it's good practice not to do so, especially since they can cause issues when coupled with some hardware.

In general, Arduinos are protected from software issues. You can't burnout an Arduino with just faulty software.

There are, however, many ways to fry an Arduino via hardware.


100% certain? No. 99.9999[Repeating]%? Yes

Here's a couple problems you could run into:

  • Using pins 0 and 1 when connected to USB (wouldn't damage it, the USB chip if on a board with a separate USB chip would probably ignore the "corrupted" data.)
  • You never mentioned your board. If it's a Uno and you modified your USB firmware, there might be some issues reflashing your board if you forget that you flashed it with a keyboard firmware. It won't damage it, but you may think it's bricked if you forget to reflash it.
  • If you only disconnect a couple pins and leave others in, it may give wierd results and fry the Arduino or whatever is partially attached
  • If you make any physical modifications to the board

The second to last one is the one you really have to worry about. I have seen previous discussions about destroying a board with a sketch, but nothing has been suggested.

Lastly, there a chance you can damage it with setting the fuses on the chip(s) on the board.

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