# Ultrasonic to servo motor using arduino

**URL:** <https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994>\
**Category:** Sensors\
**Created:** [September 22, 2024, 11:37am UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994 "2024-09-22T11:37:14Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![veevieneane1](https://avatars.discourse-cdn.com/v4/letter/v/a87d85/32.png) [@veevieneane1](https://forum.arduino.cc/u/veevieneane1)\
**Post date:** [September 22, 2024, 11:37am UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994/1 "2024-09-22T11:37:14Z")

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![circuit_image](https://europe1.discourse-cdn.com/arduino/original/4X/0/e/8/0e88f69a7690a16b5d1a163b339d586e661fb7a5.jpeg)

it does not move when detected. although it moved back then

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**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\
**Post date:** [September 22, 2024, 11:56am UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994/2 "2024-09-22T11:56:27Z")

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Have you written code and uploaded it to Uno?

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<div class="post-metadata">

**Author:** ![veevieneane1](https://avatars.discourse-cdn.com/v4/letter/v/a87d85/32.png) [@veevieneane1](https://forum.arduino.cc/u/veevieneane1)\
**Post date:** [September 22, 2024, 1:00pm UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994/3 "2024-09-22T13:00:47Z")

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yes

```arduino
SERVO VIA ULTRASONIC
#include <Servo.h>

// constants won't change
const int TRIG_PIN = 9; // Arduino pin connected to Ultrasonic Sensor's TRIG pin
const int ECHO_PIN = 10; // Arduino pin connected to Ultrasonic Sensor's ECHO pin
const int SERVO_PIN = 5; // Arduino pin connected to Servo Motor's pin
const int DISTANCE_THRESHOLD = 10; // 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
  pinMode(13, OUTPUT); // set arduino pin to input mode
  servo.attach(SERVO_PIN); // attaches the servo on pin 5 to the servo object
  servo.write(0);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  digitalWrite(13, 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(180); // 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);
}

```

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<div class="post-metadata">

**Author:** ![jim-p](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/jim-p/32/922840_2.png) [@jim-p](https://forum.arduino.cc/u/jim-p)\
**Post date:** [September 22, 2024, 1:31pm UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994/4 "2024-09-22T13:31:16Z")

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Try this:

```arduino
//SERVO VIA ULTRASONIC
#include <Servo.h>

// constants won't change
const int TRIG_PIN = 9; // Arduino pin connected to Ultrasonic Sensor's TRIG pin
const int ECHO_PIN = 10; // Arduino pin connected to Ultrasonic Sensor's ECHO pin
const int SERVO_PIN = 5; // Arduino pin connected to Servo Motor's pin
const int DISTANCE_THRESHOLD = 10; // centimeters

Servo servo; // create servo object to control a servo

// variables will change:
unsigned long duration_us;
float distance_cm;

void setup() {
  Serial.begin (9600); // initialize serial port
  pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode
  digitalWrite(TRIG_PIN, LOW); // set LOW
  pinMode(ECHO_PIN, INPUT); // set arduino pin to input mode
  //pinMode(13, OUTPUT); // set arduino pin to output
  servo.attach(SERVO_PIN); // attaches the servo on pin 5 to the servo object
  servo.write(0);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  //digitalWrite(13, 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 = 0.0172 * (float) duration_us;

  // ***************************************************************
  // if distance is less then DISTANCE_THRESHOLD move to 90 degrees
  // else set to 0 degrees
  // ***************************************************************

  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);
}
```

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<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [March 21, 2025, 1:32pm UTC](https://forum.arduino.cc/t/ultrasonic-to-servo-motor-using-arduino/1303994/5 "2025-03-21T13:32:03Z")

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