int PIN_LED = 8;
int PIN_BUTTON = 9;
void setup() {
pinMode(PIN_LED, OUTPUT);
pinMode(PIN_BUTTON, INPUT);
}
int prevButton = LOW;
int ledOn = LOW;
void loop() {
int currButton = digitalRead(PIN_BUTTON);
if(prevButton == LOW && currButton == HIGH) {
ledOn = HIGH;
} else if(prevButton == HIGH && currButton == LOW) {
ledOn = LOW;
}
prevButton = currButton;
digitalWrite(PIN_LED, ledOn);
}