I am using a LM2197 to convert AC pulses to DC for displaying on an analogue meter. This works as expected, using a stepper motor as a pulse generator. I now want to use an old hacked Microsoft PS2 mouse to get one of its opto switches to work as the sensor, but have run into problems. I have powered up the mouse with 5V and ground, pins 3 and 4 on the male mini DIN plug, but can't get any output from either of the remaining two output wires on the mouse leads. Does the signal need amplifying, or can the raw opto pulses be tapped off directly?