Arduino Voting Machine

Key Features:

• Every step of the polling operation will be under the control of the supervisor.
• Password-enabled security system.
• Poll results can be obtained instantly.
• Voters will be aware of the candidate he is voting for.

This simple project can be done with minimal components. The parts list are given below

1. Arduino Uno - 1
2. 16x2 LCD -1
3. Push Buttons - As required
4. Potentiometer 100k - 1
5. Breadboard - 1
6. Connecting Wires - As required.

                                                                                             DESIGN

The design of the voting machine was given here. The Arduino reads the keypad input through the process of Polling. A 16x2 LCD was connected to the PORTD in 4-bit mode. In order to operate this system, you will need to plug the Arduino into your PC and control it using Arduino IDE's serial monitor by plugging it into the PC.

Now connect the buttons to a breadboard as shown in the diagram. You can increase the number of buttons you use based on the number of candidates for the poll. Affix the LCD along with the potentiometer to the board and finish up all the connections as shown in the schematic design.

ALGORITHM TO CODE:

1. Initialize the serial connection in your Arduino.

2. Wait for password input and check the input password matches with default one once it is entered.

3. If the input password is correct, grant access to the user unable to give command input.

4. If “V” is pressed, start scanning the keypad to detect the vote input.

5. Allow only one single input by the voter and again wait for further command.

6. If “D” is pressed, send the poll tally to the serial monitor from the Arduino.

STEPS TO CONDUCT A POLL:

1. Open the Arduino IDE and then the serial monitor.

2. Enter the correct password.

3. Press “V” to allow voters to cast their vote.

4. Press “D” to display poll results.

5. As part of the voting process, each time a voter casts a vote, he or she must press the "V" symbol in order to give the next voter an opportunity to cast a vote.

CODE:

#include 
int votes[4]={0,0,0,0};
char inbyte;
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);         //LCD connections
  String pwd="VOTE";                         //Default Password
  String inpt="";
  boolean flag=false;
  boolean securitygranted=false;           
  int i;

void setup() {
  pinMode(A2, INPUT_PULLUP);              //Setting pins as input
  pinMode(A3, INPUT_PULLUP);
  pinMode(A4, INPUT_PULLUP);
  pinMode(A5, INPUT_PULLUP);
  lcd.begin(16, 2);
  lcd.display();
  Serial.begin(9600);                    //Begin serial communication
  Serial.println("ENTER PASSWORD");
}

void loop() {
  while(flag==true)                     //Check flag for "V" command
  {
  if(digitalRead(A2) == LOW) 
  {
  flag=false;
  lcd.print("MARK");                  //Example candidate name
  votes[0]=votes[0]+1;
  }
  else if(digitalRead(A3) == LOW)
  {
  flag=false;
  lcd.print("JILL");
  votes[1]=votes[1]+1;
  }
  else if(digitalRead(A4) == LOW) 
  {
  flag=false;
  lcd.print("JACK");
  votes[2]=votes[2]+1;
  }
  else if(digitalRead(A5) == LOW)
  {
  flag=false;
  lcd.print("TOMY");
  votes[3]=votes[3]+1;
  }
  }
}

void serialEvent()                     
{
  while(Serial.available())
  {
   inbyte=(char)Serial.read();                   //Reading incoming character
   if(securitygranted==false)
   {
    inpt += inbyte;
    inbyte='\n';
   }   
  }
  commandcheck();
}

void commandcheck()                         
{
  switch (securitygranted)                    //See for the security permissions
  {
    case false: {
      if(inpt==pwd)                          //Checking for password match
        {
          securitygranted=true;
          inbyte='\n';
          inpt="";
          Serial.println("ACCESS GRANTED");
        }
       else if((inpt!=pwd)&&(inpt.length()>3))        //Mismatch
       {
          Serial.println(inpt);
          inpt=""; 
          inbyte='\n';
          Serial.println("WRONG PASSWORD");
          Serial.println("ENTER PASSWORD");
          Serial.end();
          delay(100);
          Serial.begin(9600);
       }
       break;
              }
              
   case true: {
      if(inbyte=='V')             
        {
          flag=true;                             //Allowing voter to cast a single vote
          Serial.println("OK");
          lcd.clear();
          inbyte='\n';
        }
      else if(inbyte=='D')
        {
          for(i=0;i<=3;i++)                       //Displaying vote tally
          Serial.println(votes[i]);
          inbyte='\n';
        }
      else
        {Serial.println("UNKNOWN COMMAND");}
        break;
             }
  }
}