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Arduino - Ultrasonic Sensor - Servo Motor
We will learn:
- If the object is close to ultrasonic sensor, rotate servo motor to 90 degree
- If the object is far from ultrasonic sensor, rotate servo motor back to 0 degree.
Hardware Required
| 1 | × | Arduino UNO or Genuino UNO | |
| 1 | × | USB 2.0 cable type A/B | |
| 1 | × | Ultrasonic Sensor | |
| 1 | × | Servo Motor | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) 9V Power Adapter for Arduino | |
| 1 | × | (Optional) Screw Terminal Block Shield for Arduino |
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About Servo Motor and Ultrasonic Sensor
If you do not know about servo motor and ultrasonic sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:
Wiring Diagram
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Arduino Code - Ultrasonic Sensor Controls Servo Motor
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-ultrasonic-sensor-servo-motor
*/
#include <Servo.h>
// 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 = 50; // 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);
}
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
※ NOTE THAT:
The above code is for the learning purpose. The ultrasonic sensor is very sensitive to noise. If you want to use the ultrasonic sensor in practice, you should filter noise for the ultrasonic sensor. See how to filter noise for ultrasonic sensor
Video Tutorial
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Ultrasonic Sensor and Servo Motor on Commercial Products
Function References
The Best Arduino Starter Kit
See Also
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