SmartAssist EV - Strict Priority Hierarchy with Tactile Mechanical Bumpers - Part 6

Ultrasonic sensors can miss low-profile objects, clear glass, or acoustic-absorbing fabrics. To handle these blind spots, we add physical Tactile Bumper Switches (CollisionPin_L, CollisionPin_R) as a final layer of defense.To manage all these inputs, the code uses a Strict Priority Hierarchy inside the core runtime evaluation loop:Priority 1 (Highest): Tactile Impact Check. If a physical collision is registered, the robot stops everything, backs up, and executes a wide turning maneuver.Priority 2 (Medium): Ultrasonic Proactive Clearance. If an object is detected within 30cm, the robot performs a quick corrective turn to avoid an accident.Priority 3 (Lowest): Standard Path Following. If both safety systems report a clear path, the robot continues tracking the line.

The full software build adds tactical mechanical bumper microswitches routed to pins A4 (18) and A5 (19). This program runs a rigorous hierarchy matrix: physical bumper triggers grab immediate absolute priority (initiating multi-second reversing maneuvers), sonar triggers handle medium-priority non-contact adjustments, while line following proceeds only when both safety nets report a clear path.

Here is the final, production-ready source architecture merging all four functional modules:



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

// --- COMPREHENSIVE HARDWARE PIN CONFIGURATION ---
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; 

const int trigPin = 4;      
const int echoPin = 3;      

// Physical Tactile Bumpers (Mapped to available analog pins working as digital inputs)
const int CollisionPin_L = 18; // Pin A4
const int CollisionPin_R = 19; // Pin A5

// Line Tracking Photo-interrupters
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 spd = 195;              // Specific heavy escape/evasive speed vector
int trackSpeed = 200;       

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);
}

float getDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  long duration = pulseIn(echoPin, HIGH, 30000); 
  float d = duration * 0.0343 / 2;
  
  if (d == 0) return 999.0; 
  return d;
}

void exec_cmd(byte key_val) {
  switch (key_val) {
    case 0x1C: 
      if (currentMode == MODE_MANUAL) {
        currentMode = MODE_AUTONOMOUS;
        Serial.println("System Notification: AUTONOMY MODE ENGAGED.");
      } else {
        currentMode = MODE_MANUAL;
        motor(0, 0, 0, 0); 
        Serial.println("System Notification: MANUAL OVERRIDE ENGAGED.");
      }
      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(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // Initialize switches using internal pullups (Switches must connect directly to GND)
  pinMode(CollisionPin_L, INPUT_PULLUP);
  pinMode(CollisionPin_R, INPUT_PULLUP);
  
  pinMode(TrackingPin_L, INPUT_PULLUP);
  pinMode(TrackingPin_R, INPUT_PULLUP);
  
  Serial.println("System Core Ready.");
}

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) {
    float distance = getDistance();
    
    // Evaluate binary conditions of active bumper connections
    int sumVal = (digitalRead(CollisionPin_L) == LOW ? 1 : 0) * 2 + (digitalRead(CollisionPin_R) == LOW ? 1 : 0);
    
    // --- HIERARCHY LEVEL 1: Absolute Physical Impact Interception (Bumpers) ---
    if (sumVal > 0) {
      Serial.print("TACTILE COLLISION TRIGGERED. Code: ");
      Serial.println(sumVal);
      
      if (sumVal == 1) {      // Right-side crash -> Back up, then pivot left
        motor(spd, 0, spd, 0); delay(2000);
        motor(spd, 0, 0, spd); delay(2000);
      }
      else if (sumVal == 2) { // Left-side crash -> Back up, then pivot right
        motor(spd, 0, spd, 0); delay(2000);
        motor(0, spd, spd, 0); delay(2000);
      }
      else if (sumVal == 3) { // Frontal center crash -> Back up, then pivot left
        motor(spd, 0, spd, 0); delay(2000);
        motor(spd, 0, 0, spd); delay(2000);
      }
    }
    // --- HIERARCHY LEVEL 2: Medium Proactive Clearance Monitoring (Sonar) ---
    else if (distance < 30) {
      motor(motorSpeed, 0, 0, motorSpeed); // Fast defensive evasion left
      delay(300);
    }
    // --- HIERARCHY LEVEL 3: Standard Path Routine (Line Following) ---
    else {
      int trackL = digitalRead(TrackingPin_L);
      int trackR = digitalRead(TrackingPin_R);
      int Track = trackL * 2 + trackR;
      
      if (Track == 0)      motor(0, 0, 0, 0);
      else if (Track == 1) motor(0, trackSpeed, trackSpeed, 0);
      else if (Track == 2) motor(trackSpeed, 0, 0, trackSpeed);
      else if (Track == 3) motor(0, trackSpeed, 0, trackSpeed);
      delay(10);
    }
  }
}