Height Measurement

Note

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Kit purchase

Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

Name	Includes ESP32 board	PURCHASE LINK
ESP32 Ultimate Starter Kit	ESP32 WROOM 32E +	BUY
Universal Maker Sensor Kit		BUY

Course Introduction

This project uses an ultrasonic sensor, ESP32, and a TM1637 7‑segment display to measure object height.

A button triggers the measurement, calculating height based on the fixed sensor position. The result is shown on the 7‑segment display with 0.1 cm accuracy, and detailed distance and height data are also sent to the serial monitor.

Note

If this is your first time working with an ESP32 project, we recommend downloading and reviewing the basic materials first.

• 1.1 Install Arduino IDE(Important)

• 1.2 Introduce of Arduino IDE

• 1.4 Install the Arduino Nano ESP32 Board (Important)

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	ESP-WROOM-32 ESP32 ESP-32S Development Board	1	BUY
2	USB Type-C cable	1
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Ultrasonic Sensor Module	1	BUY
6	Button	1	BUY
7	4-Digit Segment Display Module	1	BUY

Wiring

Common Connections:

• 4-Digit Segment Display Module

  • CLK: Connect to GPIO23 on the ESP32.

  • DIO: Connect to GPIO22 on the ESP32.

  • GND: Connect to breadboard’s negative power bus.

  • VCC: Connect to breadboard’s red power bus.

• Button

  • Connect to breadboard’s negative power bus.

  • Connect to GPIO19 on the ESP32.

• Ultrasonic Sensor Module

  • Trig: Connect to GPIO5 on the ESP32.

  • Echo: Connect to GPIO18 on the ESP32.

  • GND: Connect to breadboard’s negative power bus.

  • VCC: Connect to 3.3V on the ESP32.

Writing the Code

Note

• You can copy this code into Arduino IDE.

• To install the library, use the Arduino Library Manager and search for TM1637Display and install it.

• Don’t forget to select the board(ESP32 Dev module) and the correct port before clicking the Upload button.

#include <TM1637Display.h>

#define TRIG_PIN 9
#define ECHO_PIN 10
#define CLK 2
#define DIO 3
#define BUTTON_PIN 4

TM1637Display display(CLK, DIO);

const int sensorHeight = 15;  // Fixed sensor height (cm)
bool buttonState = HIGH;      // Current button state
bool lastButtonState = HIGH;  // Previous button state
unsigned long debounceDelay = 50; // Debounce time
unsigned long lastDebounceTime = 0;

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);  // Button with pull-up input
  display.setBrightness(0x0f);
  display.showNumberDec(0, true);     // Initial display 0000
}

void loop() {
  int reading = digitalRead(BUTTON_PIN);

  // Button state change detection (debounce)
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading != buttonState) {
      buttonState = reading;
      // Button press detected
      if (buttonState == LOW) {
        measureHeight();
      }
    }
  }

  lastButtonState = reading;
}

void measureHeight() {
  // Trigger ultrasonic pulse
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Receive echo
  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.0343 / 2.0;
  float height = sensorHeight - distance;
  if (height < 0) height = 0;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.print(" cm, Height: ");
  Serial.print(height);
  Serial.println(" cm");

  // Display on 7-segment display (accuracy 0.1cm)
  int displayHeight = (int)(height * 10);  // 12.3cm -> 123
  display.showNumberDecEx(displayHeight, 0b01000000, false); // Show with decimal point
}