Question

1. Using an Arduino MEGA write the code for the following problem.

You have a pinball machine with four switches on the playboard. When a ball rolls over one of the switches that action must trigger the Arduino to add 20 points to the score being displayed on a 16x4 LCD, and actuate a relay that will trigger a bumping solenoid elsewhere on the board. The solenoid should return to home after the switch is no longer depressed by the ball.

Hint: treat the roll over switches like limit switches.

Answer 1

Arduino program for above problem:

#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
#define sw1 2
#define sw2 3
#define sw3 4
#define sw4 5
#define so1 6

//variable to store points of game
int points = 0;

void setup() {

  //setting pinmode of switches
  pinMode(sw1, INPUT);
  pinMode(sw2, INPUT);
  pinMode(sw3, INPUT);
  pinMode(sw4, INPUT);

  //seting pinmode of solenoid
  pinMode(so1, OUTPUT)
  
  //Setting the baud rate
  Serial.begin(9600);

  // setting column and row no.s in LCD
  lcd.begin(16, 4);

  //setting staring position in 16 X 4 lcd
  lcd.setCursor(1, 2)

  //printing initial score 
  lcd.print("score: 0");

}

//Lets assume we have pull up switches 
//that means arduino will read high when switch is pressed

void loop() {

    //if any switch is pressed by the pinball 
    if(digitalRead(sw1) == HIGH || digitalRead(sw2) == HIGH || digitalRead(sw3) == HIGH || digitalRead(sw4) == HIGH)
    {

      //increment the points by 20
      points += 20;

      //trigger a bumping solenoid, so1
      digitalWrite(so1, HIGH);

      //clear the lcd first
      lcd.clear();

     //show the points on lcd
     lcd.print("Score: " + String(sol));

    }
      
    //if none of the switches is pressed
    else{
       //off the solenoid so that it comes abck to home, so1
       digitalWrite(so1, HIGH);
        
     }

    

}

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