saveearth123

i need low voltage sensors that will detect when something about the size of a tiny finger passes through a beam. They will also need to be compatible with a low voltage load - about 5 volt dc. likely small relays will be needed. this is all under water but enclosed without water. this is for an aquatic project. the beam distance does not need to be more than one or two inches. no life will be harmed, of course. i see lots of sensors rated for something in your back yard or at your garage door available.