Any chance of a circuit sketch ??
Yeah. I'll work on it but here's the verbal version- this sensor is a 3 wire reflective sensor, when a reflection from a case within about .5" of the lens occurs the output activates. You'll need a 5v supply (5v board mount VR's are cheap you can probably find one pre-made for less than 5 bucks). If you are going to drive BOTH LED's with the 5v recommend a 1A VR.
This sensor, the one I could get (OPB716Z) requires a PNP 2N4401 transistor to drive the Timer switch circuit.
5v goes to the sensor 5v pin
1K pullup from 5v goes to the 2N4401 collector
2N4401 collector also goes to Timer pin 1 0v
2N4401 emitter goes to either your start or stop input Timer pin 11 or 12
2N4401 base goes to sensor output pin 'out'
sensor 0v goes to your 5v supply 0v which also needs to be tied to the Timer pin 1 0v.
Your manual start or stop switch can be wired parallel and still function.
A better one for the start switch to detect a case on top of the trapdoor is the OPB100Z, this is an interrupt style sensor, and does not require a 5v supply. It is two units, a tuned IR LED and a phototransistor. It needs to be aligned as close to axial suggest a drilled hole in the base plate.
For 12v operation-
LED black wire- ground
LED red wire 120-150 ohm 1 watt resistor to 12v
PT white wire- 12v thru 10K resistor, then tap after the resistor and put this to the base of an NPN 2N4401 transisitor
PT green wire to 0v
2N4401 emitter to Timer pin1 0v
2N4401 collector to start or stop pin 11 or 12
For 5v operation of the OPB100Z change the LED supply resistor to 39 ohms.
The pullups can be SMD or small watt the LED resistors need to be 1w.
It is important to drive the LED to as much current as you can get away with the more power the LED has the greater the distance apart the two units will work. At these LED drive currents (80mA, 100mA MAX constant) its good for 4"-5" of distance.
And these are true infrared units, no visible light, if you aren't sure they're working put your finger on the LED voltage supply resistors
