INFRARED (IR) SPEED sensor module

Code

Code explanation

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);
   }