const int SWITCH_PIN = 7;  // the number of the switch pin
const int LED_PIN =  3;   // the number of the LED pin
const int DELAY_PIN = A1;
const int fMin = 150; // set the flasher min
const int fMax = 1000; // set the flaser max
bool lampState = LOW;
int delayTime = 100; // set initial value of flasher speed
int switchState = 0;   // variable for reading the switch status

void setup() {
  // initialize the LED pin as an output:
  pinMode(LED_PIN, OUTPUT);
  // initialize the switch pin as an pull-up input:
  // the pull-up input pin will be HIGH when the switch is open and LOW when the switch is closed.
  pinMode(SWITCH_PIN, INPUT_PULLUP);
  pinMode(DELAY_PIN, INPUT);
}
void loop() {
  // read the state of the pushbutton and variable resistor value:
  delayTime = map(analogRead(DELAY_PIN), 0, 1023, fMin, fMax);
  switchState = digitalRead(SWITCH_PIN);
  // control LED according to the state of switch
  if(switchState == LOW)    {
     digitalWrite(LED_PIN, lampState);  // flash LED
     lampState = !lampState;
     delay(delayTime);
  }      // If switch is closed
  else                           // otherwise
    digitalWrite(LED_PIN, LOW);  // turn off LED
}