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ESP32 - Ultrasonic Sensor - Servo Motor
This tutorial instructs you how to use ESP32 with the potentiometer to control servo motor. In detail:
- The ESP32 automatically rotates a servo motor to 90° if an object is close to ultrasonic sensor
- The ESP32 automatically rotates a servo motor to back to 0° if an object is far from ultrasonic sensor
Hardware Used In This Tutorial
| 1 | × | ESP-WROOM-32 Dev Module | |
| 1 | × | Micro USB Cable | |
| 1 | × | Ultrasonic Sensor | |
| 1 | × | Servo Motor | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) 5V Power Adapter | |
| 1 | × | (Optional) DC Power Jack | |
| 1 | × | (Optional) ESP32 Screw Terminal Adapter |
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Introduction to Servo Motor and Ultrasonic Sensor
We have specific tutorials about servo motor and ultrasonic sensor. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
ESP32 Code - Ultrasonic Sensor Controls Servo Motor
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-ultrasonic-sensor-servo-motor
*/
#include <Servo.h>
#define TRIG_PIN 23 // ESP32 pin GIOP23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 22 // ESP32 pin GIOP22 connected to Ultrasonic Sensor's ECHO pin
#define SERVO_PIN 26 // ESP32 pin GIOP26 connected to Servo Motor's pin
#define 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 ESP32 pin to output mode
pinMode(ECHO_PIN, INPUT); // set ESP32 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 Instructions
- If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
- Do the wiring as above image.
- Connect the ESP32 board to your PC via a micro USB cable
- Open Arduino IDE on your PC.
- Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
- On Arduino IDE, Navigate to Tools Manage Libraries
- Type ESP32Servo on the search box, then look for the keypad library by Mark Stanley, Alexander Brevig
- Click Install button to install servo motor library for ESP32.
- Copy the above code and paste it to Arduino IDE.
- Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
- Move your hand in front of sensor
- See the change of servo motor
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