Note

Hello, welcome to the SunFounder Raspberry Pi & Arduino & ESP32 Enthusiasts Community on Facebook! Dive deeper into Raspberry Pi, Arduino, and ESP32 with fellow enthusiasts.

Why Join?

• Expert Support: Solve post-sale issues and technical challenges with help from our community and team.

• Learn & Share: Exchange tips and tutorials to enhance your skills.

• Exclusive Previews: Get early access to new product announcements and sneak peeks.

• Special Discounts: Enjoy exclusive discounts on our newest products.

• Festive Promotions and Giveaways: Take part in giveaways and holiday promotions.

👉 Ready to explore and create with us? Click [here] and join today!

Lesson 07: Infrared Speed Sensor Module

In this lesson, you will learn how to measure motor speed using a speed sensor module with an Arduino Uno. We’ll cover setting up the motor and sensor, programming the Arduino to calculate revolutions per second, and displaying the data. This project is great for intermediate learners as it provides hands-on experience with real-time data processing and motor control on the Arduino 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
Arduino UNO R3 or R4	BUY
Breadboard	BUY
Infrared Speed Sensor Module	BUY
TT Motor	-
L9110 Motor Driver Module	-

Wiring

Code

Code Analysis

1. Setting up the pins and initializing variables. Here, we define the pins for the motor and the speed sensor. We also initialize variables that will be used to measure and calculate the speed of the motor.

   // Define the sensor and motor pins
   const int sensorPin = 11;
   const int motorB_1A = 9;
   const int motorB_2A = 10;
   
   // Define variables for measuring speed
   unsigned long start_time = 0;
   unsigned long end_time = 0;
   int steps = 0;
   float steps_old = 0;
   float temp = 0;
   float rps = 0;
   

2. Initialization in the setup() function. This section sets up the serial communication, configures the pins’ modes, and sets the initial motor speed.

   void setup() {
     Serial.begin(9600);
     pinMode(sensorPin, INPUT);
     pinMode(motorB_1A, OUTPUT);
     pinMode(motorB_2A, OUTPUT);
     analogWrite(motorB_1A, 160);
     analogWrite(motorB_2A, 0);
   }
   

3. Measuring the motor’s speed in the loop() function. In this segment, the motor’s steps are measured for a duration of 1 second. These steps are then used to calculate the revolutions per second (rps), which is then printed to the serial monitor.

   millis() returns the number of milliseconds passed since the Arduino board began running the current program.

   void loop() {
     start_time = millis();
     end_time = start_time + 1000;
     while (millis() < end_time) {
       if (digitalRead(sensorPin)) {
         steps = steps + 1;
         while (digitalRead(sensorPin))
           ;
       }
     }
     temp = steps - steps_old;
     steps_old = steps;
     rps = (temp / 20);
     Serial.print("rps:");
     Serial.println(rps);
   }