Arduino with L298N

 1/*
 2* DC Motor Encoder Test Sketch
 3* by Joesan [https://github.com/joesan]
 4* 27.12.2020
 5*
 6* Records encoder ticks for each wheel
 7* and prints the number of ticks for
 8* each encoder every 500ms
 9*
10* WARNING: This is a throw away sketch, it is here
11* just for experimental purposes.
12*
13*/
14// pins for the encoder inputs for Motor M1
15#define M1_ENCODER_A 3 // The yellow wire in the sketch above
16#define M1_ENCODER_B 4 // The green wire in the sketch above
17
18int enA = 8;
19int in1 = 9;
20int in2 = 10;
21
22// variable to record the number of encoder pulse
23volatile unsigned long m1Count = 0;
24double rpm = 0;
25unsigned long lastmillis = 0;
26
27void setup() {
28pinMode(M1_ENCODER_A, INPUT);
29pinMode(M1_ENCODER_B, INPUT);
30pinMode(enA, OUTPUT);
31pinMode(in1, OUTPUT);
32pinMode(in2, OUTPUT);
33
34// initialize hardware interrupt
35attachInterrupt(digitalPinToInterrupt(M1_ENCODER_A), m1EncoderEvent, RISING);
36
37Serial.begin(9600);
38}
39
40void loop() {
41// Turn on Motor A forward direction
42runForward(255);
43
44// Calculate the RPM every second
45if (millis() - lastmillis == 1000) {
46// Disable interrupt when calculating
47detachInterrupt(digitalPinToInterrupt(M1_ENCODER_A));
48
49    // rpm = counts / second * seconds / minute * revolutions / count
50    rpm = m1count * 60 / 979.62;      
51    Serial.print("RPM =\t");
52    Serial.println(rpm);  
53    m1Count = 0;
54    lastmillis = millis();
55
56    // Enable interrupt
57    attachInterrupt(digitalPinToInterrupt(M1_ENCODER_A), m1EncoderEvent, RISING);
58}
59}
60
61void runForward(int speed) { //speed 0-255
62analogWrite(enA, speed);
63digitalWrite(in1, HIGH);
64digitalWrite(in2, LOW);
65}
66
67void runBackward(int speed) { //speed 0-255
68analogWrite(enA, speed);
69digitalWrite(in1, LOW);
70digitalWrite(in2, HIGH);
71}
72
73void m1EncoderEvent() {
74m1Count++;
75}
76
77// encoder event for the interrupt call
78/*void m1EncoderEvent() {
79if (digitalRead(M1_ENCODER_A) == HIGH) {
80if (digitalRead(M1_ENCODER_B) == LOW) {
81m1Count++;
82} else {
83m1Count--;
84}
85} else {
86if (digitalRead(M1_ENCODER_B) == LOW) {
87m1Count--;
88} else {
89m1Count++;
90}
91} */
92}