I've fried two Arduinos before: one was an Uno, which I killed with too high of an input voltage, and the other was the ADK version of the Mega, which I never was able to conclusively determine what went wrong. This got me thinking: what are some things (perhaps not immediately obvious) that will damage Arduinos?

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    \$\begingroup\$ I've already listed a few here. I may write an answer later if nobody gets to it. \$\endgroup\$ Commented Apr 15, 2013 at 17:05
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    \$\begingroup\$ There's an excellent write-up on this, over at RuggedCircuits... It is worth reading even if you don't have destructive tendencies :-) \$\endgroup\$ Commented Apr 15, 2013 at 18:20
  • \$\begingroup\$ This question is largely opinion-based. Literally any potentially dangerous action constitutes a valid answer. \$\endgroup\$ Commented Jan 29, 2016 at 11:32
  • \$\begingroup\$ Deep-fried battered Arduino. With chips, of course. \$\endgroup\$
    – Transistor
    Commented Jan 29, 2016 at 19:28
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    \$\begingroup\$ Ruffles, that is. Not the English kind. Too mooshy. Seriously, though, there is THE MOST COMMON WAY to fry one: Feed more than 5V into the 5V pin. Much better to use the Vin pin so it goes through the regulator. That way, if you feed more than 15 and blow the regulator you can lick your wounds then still salvage the rest of the board by using a 7805 into the 5V pin. \$\endgroup\$
    – SDsolar
    Commented Sep 23, 2017 at 20:05

4 Answers 4


Some I can think of that people have done...

  1. Connecting more than 6 volts to the 5V pin. (The two ATmega chips used on most Arduino boards have an absolute max of 6V.)
  2. Connecting more than VCC (typically 5 volts) to any of the I/O pins.
  3. Not current limiting the I/O pins to less than 40mA. (E.g. driving a motor directly or not using a current limiting resistor with a LED)
  4. Connecting less than 5 volts to GND and GND to Vin or 5V (reversed power). Vin and Barrel jack do have a protection diode, but it isn't always enough.
  5. Connecting a 5 volt supply to the 5V pin while connected to USB.
  6. Changing connections while powered -- never do this!
  7. Not using flyback diodes with inductive components like motors, relays, and solenoids.

On the Uno and Mega2560 boards, which use an ATmega8u2 or 16u2 for the USB to Serial converter, it seems like whenever someone accidentally connects 12V to an I/O pin it gets blown. I don't fully understand why, but it seems like a trend.

  • \$\begingroup\$ What do you mean by changing connections ... #7? \$\endgroup\$
    – taco
    Commented Apr 17, 2013 at 3:24
  • \$\begingroup\$ I do #6 ("Changing connections while powered") all the time on all sorts of electronic systems, including arduino. As long as you know what you're doing, it's perfectly fine. It in no way deserves a "never". \$\endgroup\$ Commented Apr 17, 2013 at 6:16
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    \$\begingroup\$ @ConnorWolf Sorry but I completely disagree. Even if you know what you are doing, accidents can and WILL happen. Never change connections while powered. If you haven't had a problem yet, it is only a matter time before you do. \$\endgroup\$ Commented Apr 17, 2013 at 15:51
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    \$\begingroup\$ @JamesC4S - I'm sorry, but any time you make any statement with a "never", rather then "it depends on the context, it's generally a bad idea", you're showing your inexperience. There are areas where adding or removing connections while a system is powered can be completely harmless, and in fact very useful for troubleshooting (tweaking analog control loops is one). Any unconditional statement like yours is a sign of naïveté. \$\endgroup\$ Commented Apr 18, 2013 at 0:55
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    \$\begingroup\$ I usually plug all the wires after the flashing, since the new app might be electrically incompatible with the old one. If I should connect all the wires before I start the app, does it mean I should disconnect the Arduino after flashing? \$\endgroup\$
    – v6ak
    Commented Apr 30, 2015 at 15:34

Here's a list that I referred to in my previous answer. Expanding on it:

  • Overloading a pin: If you try to power a device with a high power rating via the Arduino GPIO pins or the Vcc/GND pins, you are in danger of burning out the pin or the entire board. There's some information on pin current limits here, as well as a specific current-related problem here.
  • Connecting more than 6V to any of the pins. If you want to use more power, use an H-bridge type chip like the L293D. The RESET pin can take up till 13V, though."The Perry Bad Journalism S"
  • Shorting a GPIO pin set on OUTPUT, HIGH to GND, or one set on OUTPUT,LOW to Vcc
  • Shorting two GPIO OUTPUT pins when one is HIGH and one is LOW
  • Using +5V to power the Arduino instead of Vin/USB. This is actually OK, but only as long as you do not:

    • Put any load on Vin
    • Do this with the jumper set on USB

    The 5V pin is not as protected as the Vin pin, and can end up destroying things.

  • Shorting anything but 0V to GND.
  • Connecting more than Vcc to any GPIO pin (generally this is sort of safe till you go above Vcc+0.5V).
  • Changing connections while the Arduino is on: It's very easy to accidentally short something.
  • Switch polarities of Vcc and GND (This happens quite often when the power jack is soldered backwards.)
  • Apply something other than 3.3V to the 3.3V pin. (This pin is for output, not input)

Finally, make sure you don't keep your Arduino on a metal surface, and try to keep it free from dust and moisture. Make sure there's nothing lying around in the same compartment as the Arduino which can end up shorting something. While making a robot, it's quite common for metal shavings to get into the board. Be sure to leave it well-covered when cutting things in situ.


According to Ruggedunino, here are the top ten most common ways to destroy your Arduino:

  1. Shorting I/O Pins to Ground
  2. Shorting I/O Pins to Each Other
  3. Apply Overvoltage to I/O Pins
  4. Apply External Vin Power Backwards
  5. Apply >5V to the 5V Connector Pin
  6. Apply >3.3V to the 3.3V Connector Pin
  7. Short Vin to GND
  8. Apply 5V External Power with Vin Load
  9. Apply >13V to the Reset Pin
  10. Exceed Total Microcontroller Current

You can find the list and the fixes here. Also, if you are very concerned, they came out with an Arduino Uno clone that protects against these things, but it is $40 plus shipping.

Some [non-common but funny] ways to destroy your Arduino (Do not attempt at home):

  • Attach it to a model rocket or fireworks
  • Put it in a pool
  • Hit it with a sledgehammer
  • Throw it off a cliff
  • Light it on fire (assuming you douse it in gasoline first)
  • Hook it up to AC mains
  • Put it out in the rain with a huge metal pole that will attract lightning and get it wet

(Well you get the point.)

Conclusion: If you double check your connections and don't do anything stupid like don't use a resistor when you should, then you should be fine. Plus, if you don't know if it will damage your board, you can pick up a cheap Arduino clone on eBay to test it out and then transfer (if you want to use the official board because... well you want to support the foundation and/or you like the name brand boards.)

Good luck not damaging your board!


One common way to mysteriously kill electronic devices is static electricity. Modern devices have some built-in protection against ESD, but if you get shocked every time you leave your chair, then sitting in that chair while tinkering with Arduino is not the smartest idea.

Another (equally mysterious) danger comes from using badly insulated solder irons. If you solder while the iron is plugged into the mains, it could leak small current into any circuit you touch it with. Usually, we're talking about micro-amperes here, so you may never notice it, but it might be enough to damage delicate CMOS transistors. The solution is to disconnect any expansion boards (shields?) before you solder on them.

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    \$\begingroup\$ I wish this was more commonly expressed. Get an anti-static wriststrap or similar when working with exposed microelectronics. The human body can generate a whopping amount of charge and then you prod your finger directly onto a microcontroller... ZAP, goodbye microcontroller. \$\endgroup\$
    – flith
    Commented Mar 2, 2018 at 12:47