I accidentally connected 12V to my Arduino UNO ground pin. My computer isn't detecting the Arduino but the Arduino is ON.
Is it definitely burned? Can I somehow save it?
Connecting 12V to the ground pin of an Arduino Uno is not by itself a harmful thing to do. What else did you do before or after that? Was a USB cable connected between the Arduino and the computer? Where did the 12V come from?
When you say that "... the Arduino is ON", what do you mean?
That usually fries the Atmega328P, which you can pull out of its socket and replace. You'll need to put a bootloader on is as well, or buy one that is already bootloaded.
However, the USB interface usually gets fried too, and if you don't have hot air rework capability you'll find that really difficult to replace. I'd say that occurred as the PC doesn't detect it anymore.
Did you happen to have the 12V ground hooked up as well? If it was JUST the 12V wire and not the ground, perhaps. If you had the 12V ground hooked up as well, it's toast.
My computer isn't detecting the Arduino but the Arduino is ON.
Do you mean the on LED is lit? If that is, then that means nothing.
Do you mean it is still running the last code you put in it? If that is the case then it is only the USB to serial chip you fried. As CrossRoads said, that is mechanically difficult to replace.
tinman13kup:
Did you happen to have the 12V ground hooked up as well? If it was JUST the 12V wire and not the ground, perhaps. If you had the 12V ground hooked up as well, it's toast.
Just the 12 V wire.
The arduino was connected to the computer.
It doesn't run the code anymore just the On LED.
Was this the 12V wire from the same computer?
What else was connected to the Arduino besides the USB cable?