อ่านเซนเซอร์ตรวจจับการเคลื่อนไหว PIR

A PIR sensor watches for changes in infrared heat. When a warm body like a person moves across its view, it fires.

PIR stands for passive infrared. It only reacts to a change in heat, so a still object soon fades from notice while motion stands out.

A typical PIR module has three pins: VCC for power, GND for ground, and OUT for the digital signal you read.

Most PIR modules run on 5V. Connect VCC to 5V and GND to ground, just like any other digital sensor.

The OUT pin gives a clean digital signal. It goes HIGH when motion is detected and LOW when the area is calm.

Tell the board that the OUT pin is an input so it can listen. Do this once inside setup().

Read the sensor with digitalRead. A returned HIGH means it just sensed movement nearby.

Wrap the reading in an if check so your code does something, like light an LED, only when motion is HIGH.

The on-board delay trimpot sets how long OUT stays HIGH after motion. Turn it to hold the signal longer or shorter.

The second trimpot adjusts sensitivity, the range at which motion triggers. Lower it to ignore far-off movement.

Give a PIR up to a minute to calibrate after power-on. Early readings can be jittery until it settles.

What does a PIR sensor actually respond to?

You wired a PIR with VCC, GND, and OUT, read it with digitalRead, and tuned the delay and sensitivity trimpots.