SENSORS/ACTUATORS

Arduino Nano ESP32 - Rotary Encoder

Arduino Nano ESP32 - Car

Arduino Nano ESP32 - Motion Sensor

Arduino Nano ESP32 - GPS

Arduino Nano ESP32 - SD Card

Arduino Nano ESP32 - Door Sensor

Arduino Nano ESP32 - RFID

Arduino Nano ESP32 - Touch Sensor

Arduino Nano ESP32 - Force Sensor

Arduino Nano ESP32 - IR Remote Control

Arduino Nano ESP32 - Flame Sensor

Arduino Nano ESP32 - TCS3200D/TCS230 Color Sensor

Arduino Nano ESP32 - Sound Sensor

Arduino Nano ESP32 - SW520D Tilt Sensor

Arduino Nano ESP32 - SW-420 Vibration Sensor

INTERNET OF THING (IoT)

Arduino Nano ESP32 - Ethernet

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

1	×	Arduino Nano ESP32
1	×	USB Cable Type-A to Type-C (for USB-A PC)
1	×	USB Cable Type-C to Type-C (for USB-C PC)
1	×	Ultrasonic Sensor
1	×	Breadboard
1	×	Jumper Wires
1	×	Optionally, DC Power Jack
1	×	Recommended: Screw Terminal Expansion Board for Arduino Nano
1	×	Recommended: Breakout Expansion Board for Arduino Nano
1	×	Recommended: Power Splitter for Arduino Nano ESP32

Or you can buy the following kits:

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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 .

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.

Ultrasonic Sensor Pinout

image source: diyables.io

How Ultrasonic Sensor Works

See How Ultrasonic Sensor Work

Wiring Diagram between Ultrasonic Sensor and Arduino Nano ESP32

The wiring diagram when powering the Arduino Nano ESP32 board via USB port.

The wiring diagram between Arduino Nano ESP32 and ultrasonic sensor

This image is created using Fritzing. Click to enlarge image

If you do not use a breadboard, wire it like this:

The wiring diagram between Arduino Nano ESP32 and ultrasonic sensor (No Breadboard)

This image is created using Fritzing. Click to enlarge image

Pushing jumper wires into the headers is quick, but the wires can slip out. Put the Arduino Nano ESP32 on a Screw Terminal Expansion Board for Arduino Nano, then tighten each wire under a screw. The wiring stays the same. Only the wires now go to the screw terminals, as shown below.

The wiring diagram between Arduino Nano ESP32 and ultrasonic sensor Screw Terminal

This image is created using Fritzing. Click to enlarge image

The wiring diagram when powering the Arduino Nano ESP32 board via Vin pin.

The wiring diagram between Arduino Nano ESP32 and ultrasonic sensor external power

This image is created using Fritzing. Click to enlarge image

The diagram below shows the same connections without a breadboard:

The wiring diagram between Arduino Nano ESP32 and ultrasonic sensor external power (No Breadboard)

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

How to upload Arduino Nano ESP32 code on Arduino IDE

Open Serial Monitor on Arduino IDE

How to 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

Newbiely | Arduino IDE 2.3.8

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Newbiely.ino

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8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'Arduino Nano ESP32' on 'COM15')

New Line

9600 baud

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

Ln 11, Col 1

Arduino Nano ESP32 on COM15

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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

Video Tutorial

Language References

Learn More

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