Note: groups.io will be down for maintenance on Wednesday, October 5th, starting at 9AM Pacific Time (4PM Wednesday October 5, 2022 UTC), for approximately one hour.
i use the same sensors SECO-LAM (Seco-Larm E-931-S35RRQ Enforcer Indoor/Outdoor Wall Mounted Photoelectric Beam Sensor with 35 Foot Range) as Dan. Also, on an MVO controls roof system.
your control will be different but the principle is the reflector can be used to make or break the circuit. you want to set it up in series with your power supply to your roof motor and only when the circuit is "made" (reflector mounted on the scope is bouncing back the beam from the transmitter mounted on the wall) will you roof motor have power.
one interesting "gotcha" i recently experienced however, the scope parked on a beautiful clear morning but the roof didn't close -- went out to the observatory and found the reflector frosted over :-o
i need to construct a little "dew shield" around it i think to prevent a recurrence. :-)