In short - I had my Arduino GPRS shield blow up on me. Catching fire and everything.
As this was obviously a serious malfunction, I'm trying to figure out what went wrong, get a better understanding of it all and see how I can avoid this in the future.
The capacitor on the GPRS shield (the red/orange block) exploded and got ripped off the board.
The Arduino board itself, although it still powers up fails to connect to a PC using USB anymore, so most likely something got killed there as well, although I don't see any physical damage.
The OBD2 Shield is also clean, but I cannot verify it at the moment.
The setup is an Arduino Mega board with the Arduino GPRS shield and an OBD2 Shield.
The setup is powered through the OBD2 Shield (12V input). That shield has a 5V regulator that can handle up to 150mA, some of it is used by the shield while the rest can power the Arduino board + other shields.
The docs of the OBD2 shield state : Use it with caution if you are sure your total power will stay under 150mA. (I guess I should interpret this as making sure the setup should not surpass 150mA ?)
At the time when the setup caught fire the following jumper wires were present that could have potentially short-circuited if they touched. I was in a hurry to test so I didn't check them properly as I usually do.
- 2 wires (TX and RX) on the OBD2 Shield
- 1 GSM TX wire on the GPRS shield
- 2 wires (SCL and SDA) on the GPRS shield
Could a short-circuit on these wires have caused the GPRS shield to catch fire ? Or should I look in the direction of the power supply ?