I am trying to program a sketch such that an LED will light up for as long as a push button is pressed down. I have tested the components and electronics configuration before with a simpler program, and it all works, but there seems to be a problem in the code. I wanted to know how my sketch may be altered so the code will work:

const int ledPin = 12;
const int switchPin = 2;
const int Time = 100;
int buttonState = 0;
int count = 0;
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(switchPin, INPUT); 

void loop() {
buttonState = digitalRead(switchPin);
while (buttonState == HIGH) {

  if (count>1) {
    digitalWrite(ledPin, HIGH);
    digitalWrite(ledPin, LOW);

  • And how exactly this doesn't work?
    – gre_gor
    Commented Aug 8, 2018 at 22:30
  • @gre_gor there is no response from the LED at all, regardless of how long, or much I press the button. When I use a simpler button-light up sketch, it works perfectly, but not with this code Commented Aug 8, 2018 at 22:46
  • 1
    Why do you increase the count value? Should the led be longer on each time the button is pressed. If so, please add that to your question. Hint: nothing stops the while.
    – Jot
    Commented Aug 8, 2018 at 22:57
  • Are you also trying to see how long the button was pressed down for?
    – VE7JRO
    Commented Aug 8, 2018 at 23:38

2 Answers 2

while (buttonState == HIGH) {

this will never exit when the button is ever high. You should also reset count after the if.

Instead you want to either do buttonState = digitalRead(switchPin); inside the loop or rejig the function to be a state machine using timestamps like blink without delay.


Try installing a 1-10k resistor to ground connected to the input pin switchPin, assuming that the pushbutton is connecting 5V to switchPin. This will force a true logic 0 when the button is not pressed.

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