Arduino Line Follower Uses a 4x4 Keypad

The line follower robot moves along a line using 5 digital line sensors. The robot moves to a place according to the button pressed on the keypad. To reach the destination and return to the starting point, the robot counts the number of intersections. https://youtu.be/OM27ro_l7Vw?si=t_K-tjHP-uffRQCF

The parts required to build:

• 1 Arduino Mega 2560 Pro
• 1 Line sensor module (5 digital line sensor)
• 1 TB6612FNG driver motor
• 2 DC motor 600rpm and bracket
• 1 4x4 Membrane Switch Keypad
• 1 Switch
• 2 Lithium 18650 battery 3.7v
• Toy

To make keypad shield I found this tutorial "How to read a 4x4 keypad using just one Arduino pin!" https://shorturl.at/ciN07

Bill of material:

• 1 Double side prototype PCB
• 3 Resistor 1.5K ohm
• 4 Resistor 390 ohm
• 1 Resistor 4.7K ohm
• 1 Capacitor 0.01 uF

Here is a short video of me using the keypad shield https://shorturl.at/zAV01 and https://shorturl.at/itKPS

In this schematic you will find the "DIY Terminal". Made of multiple male header pins and a double sided PCB prototype. Used to supply 5V power for line sensors, keypads, driver motor and infrared obstacle avoidance sensor.

About line sensors, PID and more, you can find it in my first instructable https://www.instructables.com/Arduino-Color-Sorter/

Count intersection:

This is a code update for calculating intersections, left junction and right junction:

//Count intersection
int intersection(){
  readSensor();
  if(sensor[4]==0 && sensor[0]==0){
    countIntersec++;
    stopDrive();
  }
  return countIntersec;
}


//Count left junction
int leftJunction(){
  readSensor();
  if(sensor[0]==0 && sensor[1]==0 && sensor[3]==1 && sensor[4]==1){
    countLeftJunc++;
  }
  return countLeftJunc;
}


//Count right junction
int rightJunction(){
  readSensor();
  if(sensor[4]==0 && sensor[3]==0 && sensor[2]==0 && sensor[0]==1){
    countRightJunc++;
  }
  return countRightJunc;
}

Read keypad:

Look at the picture, when button 2 of the keypad is pressed the value 151 appears.

int readKeypad(){
  int value = analogRead(A10);
  Serial.println(value);
  if(value == 208){ //Button value 1
    mode = 1; //The robot moves to the first place
  }
  if(value == 151){ //Button value 2
    mode = 2; //The robot moves to the second place 
  }
  if(value == 84){ //Button value 3
    mode = 3; //The robot moves to the third place
  }
  if(value == 5){ //Button value A
    mode  = 4; //Back to base
  }
    return mode;
}

Robot movement;

void mission(){
  goDrive();
  if(sensor[4] == 0 && sensor[0] == 0){ 
  stopDrive(); 
  mode = readKeypad();

  switch(mode){
    case 1: 
      table_1(); //First place
      break;
    case 2:
      table_2(); //Second place
      break;
    case 3:
      table_3(); //Third place
      break;
    case 4:
      goHome(); //Back to base
    case 0:
      stopDrive(); 
      break;
    }
  }
}

Robot standby:

The robot stops at the destination until the infrared obstacle avoidance sensor enters a low state and then moves back to the base.

void standBy(){
 while (digitalRead(irPin) == HIGH){
  stopDrive(); 
 }
}

  defaults();
  while(next){ 
    goDrive();
    if(intersection() == 1){ //Finish intersection
    next=0; 
    }    
  }
      stopDrive();
      standBy();
      backward(100, 100);
      turnBack(100, 100);

Obstacle robot:

The robot stops if there are obstacles on the specified path.

  stright1(100, 100);
  goDrive();

  while(next){ 
    irValue = digitalRead(irPin);
    if(irValue == HIGH){              
      goDrive();
      if(leftJunction() == 1){ //Found left junction turn left
      next=0; 
      }     
    }
    if(irValue == LOW){      
      stopDrive();
    }
  }
  turnLeft(200, 0); 

https://github.com/PC07-TS/Line-Follower-Keypad