hello all
could someone tell me how this works in principle:
Sensor door bell,Sensor door chime RD-628 sensor door bell CN;GUA products
its a shop doorbell, when you walk in it chimes. I'm interested to know how it senses someone walking in - it says with light changing, does that mean it's got a light sensor which detects a sharp change in light...as opposed to the gradual change in daytime - night time...
many thanks
could someone tell me how this works in principle:
Sensor door bell,Sensor door chime RD-628 sensor door bell CN;GUA products
its a shop doorbell, when you walk in it chimes. I'm interested to know how it senses someone walking in - it says with light changing, does that mean it's got a light sensor which detects a sharp change in light...as opposed to the gradual change in daytime - night time...
many thanks