Arduino code for button click on and off of LED. Physical Computing 2002-001

LukePhysComp_Buttony.ino

/*
Buttony
 Click an LED on and off with a button.
 
Adapted by Luke Garwood after example 4-5 from Getting Started With Arduino by Massimo Banzi and Michael Shiloh

*/


int LEDPIN = 13; //set up variable LEDPIN as the pin to which the LED connects
int BUTTONPIN = 7; //set up variable BUTTONPIN as the pin to which the button connects

int ButtonValue; // set up variable to hold value input from BUTTONPIN. 
int Old_ButtonValue; //set up variable to determine the previous value of ButtonValue

int LightOn = 0; // Used to determine whether the light is on or off, 1 being true = on, 0 being false = off


void setup() { //function that only runs once initially
  
  pinMode(LEDPIN, OUTPUT); //pinMode(pin number, either INPUT or OUTPUT)
                          //Set up LEDPIN as an output
  pinMode(BUTTONPIN, INPUT);// Set up BUTTONPIN as an Input (it recieves information from the Arduino rather than sending information/values)
}


void loop() { //function that continues to loop
  ButtonValue = digitalRead(BUTTONPIN); //digitalRead tells us if the value for this pin is HIGH or LOW
                                        //when button is pushed down digitalRead(BUTTONPIN) returns HIGH

    if((ButtonValue == HIGH) && (Old_ButtonValue == LOW)) { //a condition that asserts if ButtonValue is read as HIGH (button is pushed)
                                                            //AND was previously LOW
      LightOn = 1 - LightOn; // this alternates LightOn to be either 1 or 0 (1 being light on, 0 light off)
      delay(10); //for debouncing purposes, putting in a delay so that only one button press is registered
    }

    Old_ButtonValue = ButtonValue; //after the above code has been executed, giving Old_ButtonValue the ButtonValue to detect the moment of button press.  

    if(LightOn == 1){ // condition of if LightOn has a value of 1 (true)
      digitalWrite(LEDPIN, HIGH); //turn the LED light on by setting digitalWrite on the LED pin to HIGH
    } else { // or if the condition of LightOn is anthing other than 1 
     digitalWrite(LEDPIN, LOW); //turn, or keep, the LED off by setting digitalWrite to LOW
    }
  
}