MOSFETs susceptible to electornic discharge #1
Description
If a person charges themselves by robbing against the seats and then touches the lock, the ENGINE_OUT MOSFET will turn on and therefore the relay will switch on as well for a period of under 1 sec but still.
Weird things:
- only works if touched indirectly e.g. with the key being held at the isolating back part, does NOT work with the finger directly.
- only one mosfet turns on?
- key lock is not connected to the MOSFET directly. In fact, the part were the electronic discharge happens is not in any way connected (besides perhaps GND via the frame?) to the PCB at all. And the "sensor" cable from the ignition switch is only connected to the microcontroller via separate IO pins.
AFAIK the microcontroller does not sense an change in key state, so the discharge directly goes to the MOSFET and bypasses (?) the microcontroller.
possible fixes:
- lower pull down resistors (1k instead of 10k)
- capacitor near gate that absorbs short spikes (longer switching time is fine..)