Ok i am a little stuck on this one some help would be appreciated:
i have a 0.7V source that is coming out of another circuit (car controller) that needs to be sinked. If wire is simply connected to ground the doors will lock. If the wire is connected to a 470 Ohm resistor the doors will unlock.
I have tried an optocoupler but it appears that even under saturation conditions the doors will only UNLOCK. I am assuming that the cars controller is simply reading the voltage on that wire and locking unlocking depending voltage on that wire.
How can safely (protecting both circuits) have a digital pin control this sinking current (which is less than 10ma)...
Can i sink them directly into the DPs? is there a way i can only use one DP (pwm?!)? transistors didnt work either ...2n222 transistors but the doors would only UNLOCK...meaning the voltage is not dropped enough?
any help is appreciated.