I'm building what I thought was a simple Arduino Nano project... right up until it caught fire!
I am a long-time reader of stack exchange and I always find the answers to my questions somewhere on Google, but this seems to be a bit of a head scratcher.
The project is a 4 pin 7 segment LED screen with a timer that counts when Analog pin 0 receives a voltage signal of ~2.5-5v.
Testing the project worked as expected, but when I soldered everything together, I was getting static or white noise from the Analog pin with no voltage being supplied.
I figured I needed a Pull-Down resistor to keep the Analog pin grounded until it received a voltage signal to get rid of any interference.
I connected a 220ohm resistor DIRECTLY from GND and DIRECTLY to Analog Pin 0 and connected the voltage signal wire to Pin 0 as well.
When I actually tested the hardware while connected to the car battery, that's when it shorted out and caused a mini fire.
I was able to read the voltage with my multimeter before the chip burnt out, I was reading ~15.5v total. I'm guessing it's the car battery plus the input voltage on Pin 0.
I only do clean and precise soldering, so there were no unaccounted for connections.
I'm unsure if the issue was too many volts running through the Nano altogether or because I don't really understand how the Pull-Down resistor works and messed that up.
Please help me understand what the issue is and what I can do for a solution.