Arduino - Motion Sensor - LED

We are going to learn how to:

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×HC-SR501 Motion Sensor
1×LED
1×220 ohm resistor
1×Breadboard
4×Jumper Wires
Please note: These are affiliate links. If you buy the components through these links, We may get a commission at no extra cost to you. We appreciate it.

About LED and Motion Sensor

If you do not know about led and motion sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Motion Sensor LED Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

Initial Setting

Time Delay AdjusterScrew it in anti-clockwise direction fully.
Detection Range AdjusterScrew it in clockwise direction fully.
Repeat Trigger SelectorPut jumper as shown on the image.
arduino motion sensor initial setting

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-motion-sensor-led */ const int MOTION_SENSOR_PIN = 7; // Arduino pin connected to the OUTPUT pin of motion sensor const int LED_PIN = 3; // Arduino pin connected to LED's pin int motionStateCurrent = LOW; // current state of motion sensor's pin int motionStatePrevious = LOW; // previous state of motion sensor's pin void setup() { Serial.begin(9600); // initialize serial pinMode(MOTION_SENSOR_PIN, INPUT); // set arduino pin to input mode pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode } void loop() { motionStatePrevious = motionStateCurrent; // store old state motionStateCurrent = digitalRead(MOTION_SENSOR_PIN); // read new state if (motionStatePrevious == LOW && motionStateCurrent == HIGH) { // pin state change: LOW -> HIGH Serial.println("Motion detected!"); digitalWrite(LED_PIN, HIGH); // turn on } else if (motionStatePrevious == HIGH && motionStateCurrent == LOW) { // pin state change: HIGH -> LOW Serial.println("Motion stopped!"); digitalWrite(LED_PIN, LOW); // turn off } }

Quick Steps

  • Connect Arduino to PC via USB cable
  • Open Arduino IDE, select the right board and port
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • Arduino IDE Upload Code
  • Move your hand in front of sensor
  • See the change of LED's state

Code Explanation

Read the line-by-line explanation in comment lines of source code!

Video Tutorial

We are considering to make the video tutorials. If you think the video tutorials are essential, please subscribe to our YouTube channel to give us motivation for making the videos.

The Best Arduino Starter Kit

※ OUR MESSAGES