micro:bit Passive Infrared Movement Detector
A small version of the PIR that is used in a typical burglar alarm. It triggers when a warm body passes in front of the detector. It has some range / sensitivity setting capability and the duration of the output can be set.
The black lead goes on to GND, the red lead goes on to 3V and the yellow lead goes on to the Pin 0, 1 or 2 depending on the program.
It uses the digital input block to detect when it has been triggered.
There are two setting pots (potentiometers):
The left pot sets the duration of the output from 1 to 20 seconds. As shown, it turns through 180, fully anti-clockwise (pointing left) is 1 second, fully clockwise (pointing right) is 20 seconds. There is a three second delay before it can be triggered again.
The right hand pot sets the sensitivity / range from close to around 5m. As shown, it turns through 180, fully anti-clockwise (pointing left) is most sensitive, fully clockwise (pointing right) is least sensitive requiring larger movements close in.
The unit needs time to settle when turned on, somewhere of the order of 60 seconds.