Arduino - Motion Sensor - Servo Motor

We will learn:

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×HC-SR501 Motion Sensor
1×Servo Motor
n×Jumper Wires
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About Servo Motor and Motion Sensor

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

Wiring Diagram

Arduino Motion Sensor Servo Motor 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 - Motion Sensor Controls Servo Motor

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-motion-sensor-servo-motor */ #include <Servo.h> // constants won't change const int MOTION_SENSOR_PIN = 7; // Arduino pin connected to motion sensor's pin const int SERVO_PIN = 9; // Arduino pin connected to servo motor's pin Servo servo; // create servo object to control a servo // variables will change: int angle = 0; // the current angle of servo motor int lastMotionState; // the previous state of motion sensor int currentMotionState; // the current state of motion sensor void setup() { Serial.begin(9600); // initialize serial pinMode(MOTION_SENSOR_PIN, INPUT); // set arduino pin to input mode servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(angle); currentMotionState = digitalRead(MOTION_SENSOR_PIN); } void loop() { lastMotionState = currentMotionState; // save the last state currentMotionState = digitalRead(MOTION_SENSOR_PIN); // read new state if (currentMotionState == LOW && lastMotionState == HIGH) { // pin state change: LOW -> HIGH Serial.println("Motion detected!"); servo.write(90); } else if (currentMotionState == HIGH && lastMotionState == LOW) { // pin state change: HIGH -> LOW Serial.println("Motion stopped!"); servo.write(0); } }

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
  • Move your hand in front of sensor
  • See the change of servo motor

Video Tutorial

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Motion Sensor and Servo Motor on Commercial Products

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  • Motion Sensor Alarm
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  • Otto DIY Robot Builder Kit

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