[HayZee518]

the two electric eyes have to be in perfect alignment with each other. The receiver eye needs to be oriented so it doesn't see sunlight - it operates off infrared light from the source LED and sunlight has loads of infrared light. The down force limit switch needs to be fine tuned as it functions by detecting a rise in motor current. When the door strikes an object and the door sort of stalls, motor current rises. It's current sensitive relay detects this rise in current and operates the reversing relay which opens the door. You also have a down travel limit switch. This is entirely mechanical and operates off a cam device on the chain or drive screw - depending on your door opener.