Arduino Nano ESP32 - Ultrasonic Sensor
This tutorial provides instructions on how to use Arduino Nano ESP32 with the ultrasonic sensor HC-SR04 to measure the distance to an object.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.
Additionally, some of these links are for products from our own brand, DIYables.
Overview of Ultrasonic Sensor
The ultrasonic sensor HC-SR04 is used to measure the distance from the sensor to an object by using ultrasonic waves.
Ultrasonic Sensor Pinout
The ultrasonic sensor HC-SR04 includes four pins:
- VCC pin: connect this pin to VCC (5V)
- GND pin: connect this pin to GND (0V)
- TRIG pin: this pin receives a control pulse from Arduino Nano ESP32.
- ECHO pin: this pin generates a pulse corresponding to the measured distance to Arduino Nano ESP32.
image source: diyables.io
How Ultrasonic Sensor Works
Wiring Diagram between Ultrasonic Sensor and Arduino Nano ESP32
- The wiring diagram when powering the Arduino Nano ESP32 board via USB port.
This image is created using Fritzing. Click to enlarge image
- The wiring diagram when powering the Arduino Nano ESP32 board via Vin pin.
This image is created using Fritzing. Click to enlarge image
How To Program Ultrasonic Sensor
- Generate a 10-microsecond pulse in ESP32's pin by using digitalWrite() and delayMicroseconds() functions. For example, pin D2:
digitalWrite(D2, HIGH);
delayMicroseconds(10);
digitalWrite(D2, LOW);
- Measures the pulse duration (µs) in ESP32's pin by using pulseIn() function. For example, pin D3:
duration_us = pulseIn(D3, HIGH);
- Calculate distance (cm):
distance_cm = 0.017 * duration_us;
Arduino Nano ESP32 Code
/*
* This Arduino Nano ESP32 code was developed by newbiely.com
*
* This Arduino Nano ESP32 code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-ultrasonic-sensor
*/
#define TRIG_PIN D2 // The Arduino Nano ESP32 pin connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN D3 // The Arduino Nano ESP32 pin connected to Ultrasonic Sensor's ECHO pin
float duration_us, distance_cm;
void setup() {
// begin serial port
Serial.begin (9600);
// Configure the trigger pin to output mode
pinMode(TRIG_PIN, OUTPUT);
// Configure the echo pin to input mode
pinMode(ECHO_PIN, INPUT);
}
void loop() {
// Produce a 10-microsecond pulse to the TRIG pin.
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
// Measure the pulse duration from the ECHO pin
duration_us = pulseIn(ECHO_PIN, HIGH);
// calculate the distance
distance_cm = 0.017 * duration_us;
// print the value to Serial Monitor
Serial.print("distance: ");
Serial.print(distance_cm);
Serial.println(" cm");
delay(500);
}
Detailed Instructions
- If this is the first time you use Arduino Nano ESP32, see how to setup environment for Arduino Nano ESP32 on Arduino IDE.
- Copy the above code and paste it to Arduino IDE.
- Compile and upload code to Arduino Nano ESP32 board by clicking Upload button on Arduino IDE
- Open Serial Monitor on Arduino IDE
- Move your hand in front of ultrasonic sensor
- See the distance from the sensor to your hand on Serial Monitor
COM6
distance: 19.4 cm
distance: 17.6 cm
distance: 16.9 cm
distance: 27.4 cm
distance: 26.9 cm
distance: 24.3 cm
distance: 25.6 cm
distance: 23.1 cm
Autoscroll
Clear output
9600 baud
Newline
Line-by-line Code Explanation
The above Arduino Nano ESP32 code contains line-by-line explanation. Please read the comments in the code!
How to Filter Noise from Distance Measurements of Ultrasonic Sensor
See How to Filter Noise from Distance Measurements of Ultrasonic Sensor