have had an Arduino Nano for a project I was building, but suddenly it burnt out and would not upload sketch anymore.
I tried it with an Arduino Nano clone from China, which also burned out within 10 minutes. I have absolutely NO idea what happened and why...
Dear fellow troubleshooting detectives, please help me find the method these Arduinos were brutally executed.
The project included following components:
1 x 5V relay for Arduino (regular cheap type sold everywhere)
1 x RC522 RFID card reader module
1 x Arduino Nano (real)
1 x Arduino Nano (clone)
1 x Arduino Nano Screw Terminal
1 x 12V solenoid spring lock (springs open when 1 second pulse 12v are applied)
Wired like this:
Arduno Nano put inside Screw Terminal adapter, which was screwed onto a wooden plate. The RC522 was hooked up to the Arduino the following way. Dupont cables were screwed into the screw terminals to keep them tight.
522 Wiring(RC522 left, arduino right):
GND - GND on Arduino
V - 5V on Arduino
S - D4 on Arduino
The Arduino was powered through an external power supply with stable 12V power directly through Vin and Gnd. The 12V power supply also supplied power to the relays COM port, and then through NO to a light. I had the positive side of the power supply go into a 3-way Wago clamp, dividing power to Arduino Nano and to COM part of relay. The negative part went into a 3-way with Arduino Nano and the Solenoid.
The thing was that when the card reader found a card with a certain ID, it would trigger the solenoid for 1-2 seconds. Now what happened was that the Arduino Nano worked a total of 7-8 times before it got violently hot and suddenly would not read RFID card anymore. It would also no longer upload sketches(avr500 time out). I changed the real nano with a clone nano(just popped it into the screw shield when changing nanos). The new one also burned out within 5-10 minutes. It smelled burnt.
During the time it was burning out, I had the nano hooked up to my computer to change some parameters. Not sure if this is why it happened.
After burning out all the Nanos I have on hand, I exchanged it for a Arduino Uno clone(a duemilove) and this has been working perfectly for a while.
Now - I have a few suspects:
- The screw shield. Maybe I shorted it out when I screwed it onto the wood? The screws covered the entire hole, and it may have been large enough to connect parts of the pcb board to eachother?
- The nanos had some sort of defect - however, this would probably not affect both the clone and real?
- Maybe some electrical surge goes back to the Arduino from the relay?
What could be wrong with my project here?