I have an appliance that needs a +12v pulse to be activated and a -12v pulse to be deactivated on the same input pin. After the pulse, the line should drop to 0v again. This voltage switching only has to happen once and a while. So at a very low frequency.
I think/know the outputs of a rpi can not produce negative voltage but I need a circuit that can put 0v, +12v or -12v on a line.
I guess I will need two output pins of a rpi to switch between 0v, +12v and -12v but I have no idea how to create the circuit.
Will I need to have two power-supplies to produce both +12v and -12v? Or are there IC's that only need +12v to do the job?
So if I have two input pins to the circuit (outputs from PI) i1 and i2 then the output o of the circuit should be:
i1 = 0 & i2 = 0 => o = 0 i1 = 1 & i2 = 0 => o = +12v i1 = 0 & i2 = 1 => o = -12v i1 = 1 & i2 = 1 => should not happen but should not damage circuit.