The HC-SR501 is the most common PIR (Passive Infrared) motion module in hobby electronics, and beyond the basic "detect movement" wiring, it has two…
A quick rundown of four essential sensors: the LDR light sensor, PIR motion sensor, infrared receiver, and tilt sensor.
Build an educational Arduino PIR motion alarm, including wiring, warm-up time, sensitivity adjustment, false-trigger reduction, and safe limitations.