Motions Sensor Detection Alarm Arduino Tutor Posted by: Waqas Farooq April 16, 2021 In this post you are going learn how to make motion sensor alarm read this post and check the video and circuit diagram and code is also given belowVideo of this projectCircuit Diagram of this projectCode of this project #include // constants won't change const int TRIG_PIN = 6; // Arduino pin connected to Ultrasonic Sensor's TRIG pin const int ECHO_PIN = 7; // Arduino pin connected to Ultrasonic Sensor's ECHO pin const int SERVO_PIN = 9; // Arduino pin connected to Servo Motor's pin const int DISTANCE_THRESHOLD = 20; // centimeters Servo servo; // create servo object to control a servo // variables will change: float duration_us, distance_cm; void setup() { Serial.begin (9600); // initialize serial port pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode pinMode(ECHO_PIN, INPUT); // set arduino pin to input mode servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(0); } void loop() { // generate 10-microsecond pulse to TRIG pin digitalWrite(TRIG_PIN, HIGH); delayMicroseconds(10); digitalWrite(TRIG_PIN, LOW); // measure duration of pulse from ECHO pin duration_us = pulseIn(ECHO_PIN, HIGH); // calculate the distance distance_cm = 0.017 * duration_us; if(distance_cm < DISTANCE_THRESHOLD) servo.write(90); // rotate servo motor to 90 degree else servo.write(0); // rotate servo motor to 0 degree // print the value to Serial Monitor Serial.print("distance: "); Serial.print(distance_cm); Serial.println(" cm"); delay(500); }