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Topic: Cheap PIR motion sensor from Ebay wiring question (Read 1 time) previous topic - next topic

Scott Baker

I bought a cheap PIR motion sensor from Ebay and I'm not sure how I should be wiring this thing up. I'm assuming 5v to +, Ground to -, and a digital input pin to "Out". Anyone have any idea if I should use a pullup/pulldown resistor? There is very little info to go along with the sensor, so I'm in the dark.


Aug 30, 2012, 02:24 am Last Edit: Aug 30, 2012, 02:26 am by Automative Reason: 1

The sensor will make a vieuw of the room in the first seconds it's powered up.
When there is a detection, it will set it's output pin to LOW.

So a pull up resistor is required.

A simple code like this would give you an alarm over serial
Code: [Select]

int pirPin = 2; //digital 2

void setup(){
pinMode(pirPin, INPUT);

void loop(){
 int pirVal = digitalRead(pirPin);

 if(pirVal == LOW){ //was motion detected
   Serial.println("Motion Detected");

The code is from a bildr.org tutorial on a simular sensor

Scott Baker


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