[ladyada] has a freshly-published and amazingly thorough tutorial on passive infrared (PIR) motion sensors. Most often seen in security floodlights and automatic doors, in creative hands these sensors ...

Moderately priced Passive Infrared PIR Sensor modules are now widely available. By using these readymade and pre-configured PIR sensors, even an average electronics hobbyist can construct his/her own ...

As radar technology continues to advance, it offers an increasingly broad range of capabilities, making it a viable alternative to traditional passive infrared (PIR) sensors. With radar’s enhanced ...