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Lesson 07: Infrared Speed Sensor Module

In this lesson, you’ll learn how to use an ESP32 Development Board with a Speed Sensor Module to detect obstructions. We’ll see how the sensor sends a high signal when there’s an obstruction and a low signal when the path is clear. This project is ideal for those looking to grasp sensor integration and basic input/output operations in a practical setting using the ESP32 platform.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Universal Maker Sensor Kit	94	Universal Maker Sensor Kit

You can also buy them separately from the links below.

Component Introduction	Purchase Link
ESP32 & Development Board (ESP32 Board)	BUY
Breadboard	BUY
Infrared Speed Sensor Module	BUY

Wiring

Code

Code Analysis

Define the sensor pin

The sensor pin is declared as a constant integer and is assigned pin number 25 of the ESP32.
```
const int sensorPin = 25;
```
Setup function

This function initializes the serial communication at 9600 baud rate and sets the sensorPin as an input.
```
void setup() {
  Serial.begin(9600);
  pinMode(sensorPin, INPUT);
}
```
Loop function

The loop function continuously checks the sensor pin’s status. If the sensor pin reads HIGH, it prints “Obstruction detected” to the Serial Monitor. If the sensor pin is LOW, it prints “Unobstructed”.
```
void loop() {
  if (digitalRead(sensorPin) == HIGH) {
    Serial.println("Obstruction detected");
  } else {
    Serial.println("Unobstructed");
  }
}
```
More

If an encoder is mounted on the motor, the rotational speed of the motor can be calculated by counting the number of times an obstruction passes the sensor within a specific period.