SmartAssist EV - Introducing Autonomous Line Following (TCRT5000) - Part 4

Manual driving is limited by line-of-sight. To implement autonomous navigation, we integrate dual Infrared Line-Tracking Sensors (TrackingPin_L and TrackingPin_R). These sensors output binary feedback depending on whether they detect a highly reflective light floor or a non-reflective dark path.To allow transitioning between manual piloting and automatic tracking, we establish a State Machine using a RobotMode enumeration. Pressing a designated toggle button (0x1C or "OK") alternates the core operating architecture.

This step implements a Finite State Machine utilizing the remote's OK button (0x1C). You can now toggle mid-flight between manual control and an automated tracking routine monitored by the optical sensors on pins A2 and A3.

#include <Arduino.h>
#include <IRremote.hpp>

const int motorPinA_1A = 5; 
const int motorPinA_1B = 6; 
const int motorPinB_1A = 9; 
const int motorPinB_1B = 10;
const int IR_RECEIVE_PIN = 2; 

// Line Tracking Sensors (Assigned to dedicated conflict-free analog pins)
const int TrackingPin_L = A2;
const int TrackingPin_R = A3;

enum RobotMode {
  MODE_MANUAL,     
  MODE_AUTONOMOUS  
};

RobotMode currentMode = MODE_MANUAL; 

const int motorSpeed = 200; 
int trackSpeed = 200; // Optimized track following velocity

unsigned long lastCommandTime = 0;
const unsigned long commandTimeout = 250;

void motor(int A1, int A2, int B1, int B2) {
  analogWrite(motorPinA_1A, A1);
  analogWrite(motorPinA_1B, A2);
  analogWrite(motorPinB_1A, B1);
  analogWrite(motorPinB_1B, B2);
}

void exec_cmd(byte key_val) {
  switch (key_val) {
    case 0x1C: // OK Button - Toggle Manual/Autonomous operations
      if (currentMode == MODE_MANUAL) {
        currentMode = MODE_AUTONOMOUS;
        Serial.println("Mode changed: AUTONOMOUS (Tracking Active)");
      } else {
        currentMode = MODE_MANUAL;
        motor(0, 0, 0, 0); 
        Serial.println("Mode changed: MANUAL (Remote Override)");
      }
      break;

    case 0x18: if (currentMode == MODE_MANUAL) motor(0, motorSpeed, 0, motorSpeed); break;
    case 0x08: if (currentMode == MODE_MANUAL) motor(motorSpeed, 0, 0, motorSpeed); break;
    case 0x5A: if (currentMode == MODE_MANUAL) motor(0, motorSpeed, motorSpeed, 0); break;
    case 0x52: if (currentMode == MODE_MANUAL) motor(motorSpeed, 0, motorSpeed, 0); break;
    default:   if (currentMode == MODE_MANUAL) motor(0, 0, 0, 0); break;
  }
}

void setup() {
  Serial.begin(9600);
//  pinMode(motorPinA_1A, OUTPUT);
//  pinMode(motorPinA_1B, OUTPUT);
//  pinMode(motorPinB_1A, OUTPUT);
//  pinMode(motorPinB_1B, OUTPUT);
  
  IrReceiver.begin(IR_RECEIVE_PIN, ENABLE_LED_FEEDBACK); 

  pinMode(TrackingPin_L, INPUT_PULLUP);
  pinMode(TrackingPin_R, INPUT_PULLUP);
}

void loop() {
  if (IrReceiver.decode()) {
    byte command = IrReceiver.decodedIRData.command;
    exec_cmd(command);
    if (currentMode == MODE_MANUAL) lastCommandTime = millis();
    IrReceiver.resume(); 
  }

  if (currentMode == MODE_MANUAL) {
    if (millis() - lastCommandTime > commandTimeout) {
      motor(0, 0, 0, 0);
    }
  } 
  else if (currentMode == MODE_AUTONOMOUS) {
    int trackL = digitalRead(TrackingPin_L);
    int trackR = digitalRead(TrackingPin_R);
    int Track = trackL * 2 + trackR; // Binary encoding mapping sensor states
    
    if (Track == 0) {
      motor(0, 0, 0, 0);                   // Lost line entirely -> Stop
    }
    else if (Track == 1) {
      motor(0, trackSpeed, trackSpeed, 0); // Correct path: Pivot Right
    }
    else if (Track == 2) {
      motor(trackSpeed, 0, 0, trackSpeed); // Correct path: Pivot Left
    }
    else if (Track == 3) {
      motor(0, trackSpeed, 0, trackSpeed); // Center aligned -> Drive Forward
    }
    delay(10);
  }
}