Optical module sounds alarm if someone get too close to your space. Detects slight changes in light from 2 to 8ft away. Just what you need to keep someone from intruding in your office, desk, room, etc. Stays silent until light level abruptly changes from an intruder, and then sounds an irritating electronic wavering alert that resets when they leave the immediate area. The electronic alert goes on for about 4 seconds and automatically resets. The unit continuously monitors for any quick change in light levels and adjusts for slowly changing ambient light levels throughout daylight hours.
Simple to use, only requires a speaker such as our G19814 - 8Ω 15 Watt Wall Mount Speaker (not included) or any 8Ω speaker of your choice, 4.5VDC power (3AAA Batteries), wire and switch. Module uses the ULN-2232A optotinear motion detector IC that Spraque Electric made years ago. Very unique in operation, this IC can detect minute changes in light intensity and activate a built in electronic alarm sound circuit. We are selling the module only - you must provide speaker switch, battery holder and wire. Size of module is 1.25" x 2.65". See PDF for hookup info. Sold in a package of 4.