Bdtyktl

I connected an Arduino to my laptop with the USB cable.
An arduino is something like a Raspberry Pi, but then simpler. You can program it to run a robot for example.
There was a big mistake in the wiring of my arduino project (a robot).
It uses a 12.5 Volt battery, and the Arduino is probably damaged.
The stupid thing is, that when the damage happened to the Arduino, it was both connected to my laptop via USB, and connected to all wires of the electric system of the robot. So, electric current of 12.5 volt may have gone through the USB cable.
Now, when I connect a computer mouse to that USB port of my aptop, it doesn't work. When I connect the mouse to another USB port, there's no problem.

I'm afraid I damaged something in/on my laptop!

• Is 12.5 volts enough to damage something?


• What can I do to check how big the damage is?


• Is this a common problem with Arduino's or USB ports on laptops?

Is 12.5 volts enough to damage something?

Yes. Some USB ports have overvoltage protection, but some don't.

What can I do to check how big the damage is?

You already know, the USB port is dead.

Is this a common problem with Arduino's or USB ports on laptops?

It's not that uncommon to damage laptop USB ports electrically.

1. 12V can damage almost any modern CMOS chip. Typical tolerance for USB designs is 5V or less. So 12V is pretty damaging.




2. How bad the damage is? It depends on which part of USB port was exposed, VBUS, GND, or data. None of common laptops have any overvoltage protection; at most, they have protection against short electrostatic discharge pulses (ESD, human and machine discharge models), but not from continuous (more than few milliseconds) 12V exposure.

If the 12V was shorted into the ground pin, the ground trace can be fried/evaporated. It should be visible, and maybe repairable.

If VBUS was hit by 12V, all depends whether the laptop has individual high-side power control switches, fuses, or not. If the switch was fried, it can be replaced. It looks like your case is a lucky one, since other ports still work. To determine if the VBUS is ok, you need simply check if the questionable port has 5V power. If not, the switch is fried, which might be repairable.

If data lines were exposed to a prolonged 12V DC, then it is very likely that the data interface is damaged beyond repair. However, there could be a chance that external ESD protective diodes went broke, and shorted data lines either to ground or to 5V/3.3V rail. I've seen such cases. In this case the port might signal some sort of broken connection, and should be visible by USBview.exe utility. Again, checking if data lines are shorted using a DMM will help.

Still, the chances to fix this particular USB port in your laptop are slim, and it requires certain experience and skills.

3. AFAIK, the 12V voltage is not a common Arduino supply, so the question sounds moot.