statemachine.ino

#include "Arduino.h"
#define BUTTON_PIN 3
#define DELAY 30000 //milliseconds

static unsigned long time;
static unsigned int state;
static unsigned int button;
static unsigned int delay;


void setup()
{
    time = 0;
    state = 1;
}

void loop()
{
    button = digitalRead(BUTTON_PIN);
    switch state
    {
    case 1:
        if(button == HIGH) { // enter next state and save current time
            state = 2;
            time = millis();
        }
        break;
    case 2:
        if(button == HIGH) // reset timer
            time = millis();
        if(time - millis() > DELAY) //check if time has passed
            state = 1;
        break;
    }
}