Motion activated sensor detects movement and sends a wireless signal to the door chime.
This Motion Activated Door Alert is great for any entrance that doesn`t have a door that opens or closes. The sensor detects movement and the green LED on the detector unit will light up and send a wireless signal to the door chime and the chime will sound. A choice of 8 selectable melodies: Westminster, Ding-dong, Telephone Ring, Circus Theme, Banjo On My Knee, Twinkle Twinkle Little Star, It`s A Small World, or Dog Barking. Operates 1- 9 volt and 2 - C batteries (not included) and requires no wiring. Works up to 100 ft (range will be reduced through walls or ceilings). Will not work on metal door frames.