Designing and Programming an ESP32 Circuit with an Ultrasonic Sensor (HC-SR04)

Overview

This task involves designing an electronic circuit using an ESP32 development board with an HC-SR04 ultrasonic distance sensor. The circuit measures the distance between the sensor and an object and displays the measurement on the serial monitor.

Components

• ESP32 Development Board
• HC-SR04 Ultrasonic Distance Sensor
• Jumper Wires
• Breadboard (optional)

Circuit Diagram

• Trig Pin (Trigger) of the HC-SR04 is connected to GPIO5 on the ESP32.
• Echo Pin of the HC-SR04 is connected to GPIO18 on the ESP32.

Code Explanation

int Trig_pin = 5;         // Pin connected to the HC-SR04 Trigger
int Echo_pin = 18;        // Pin connected to the HC-SR04 Echo
long duration;           // Duration of the echo pulse
float speed_of_sound = 0.034; // Speed of sound in cm/µs
float dist_in_cm;        // Distance in centimeters

void setup() {
  Serial.begin(115200);  // Start serial communication at 115200 baud
  pinMode(Trig_pin, OUTPUT); // Set Trigger pin as output
  pinMode(Echo_pin, INPUT);  // Set Echo pin as input
}

void loop() {
  // Send a pulse to trigger the sensor
  digitalWrite(Trig_pin, LOW);
  delayMicroseconds(2); // Short delay to ensure a stable low signal
  digitalWrite(Trig_pin, HIGH);
  delayMicroseconds(10); // Send pulse for 10µs
  digitalWrite(Trig_pin, LOW);

  // Measure the duration of the echo pulse
  duration = pulseIn(Echo_pin, HIGH);

  // Calculate the distance in centimeters and handle errors
  if (duration > 0) {
    dist_in_cm = duration * speed_of_sound / 2; // Divide by 2 for round-trip distance
    Serial.print("Distance: ");
    Serial.print(dist_in_cm);
    Serial.println(" cm");
  } else {
    Serial.println("Error: No echo detected");
  }

  delay(100); // Wait 100 milliseconds before the next measurement
}

Usage

1. Connect the ESP32 board and the HC-SR04 sensor according to the circuit diagram.
2. Upload the provided code to the ESP32 board.
3. Open the Serial Monitor to view the distance measurements displayed in centimeters.

Customization

You can modify the code to change the behavior of the sensor, such as adjusting the measurement interval or integrating additional features.

References

• HC-SR04 Datasheet
• ESP32 Documentation