const int TRIG_PIN = 6; // Arduino pin connected to Ultrasonic Sensor's TRIG pin
const int ECHO_PIN = 9; // Arduino pin connected to Ultrasonic Sensor's ECHO pin
const int LED_PIN  = 3; // Arduino pin connected to LED's pin
const int BUTTON_PIN = 11;
const int DISTANCE_THRESHOLD = 50; // centimeters
int lastButtonState = 0;   // the previous state of button 0 = low
int currentButtonState = 0; // the current state of button 0 = low
int ledBrightness;
int sensorVal;
 

// variables will change:
float duration_us, distance_cm;
 
void setup() {
  Serial.begin (9600);       // initialize serial port
  pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode
  pinMode(ECHO_PIN, INPUT);  // set arduino pin to input mode
  pinMode(LED_PIN, OUTPUT);  // set arduino pin to output mode
  pinMode(BUTTON_PIN, INPUT);
 
  pinMode(LED_PIN, OUTPUT);
}
 
void loop() {
  // generate 10-microsecond pulse to TRIG pin
  //lastButtonState = currentButtonState;
  currentButtonState = digitalRead(BUTTON_PIN);
  if (currentButtonState = lastButtonState) {
    if (currentButtonState == HIGH) {
      Serial.println("button is pressed");
      digitalWrite(TRIG_PIN, HIGH);
      delayMicroseconds(10);
      digitalWrite(TRIG_PIN, LOW);
      // measure duration of pulse from ECHO pin
      duration_us = pulseIn(ECHO_PIN, HIGH);
      // calculate the distance
      distance_cm = 0.017 * duration_us;
 
      //Light brightness and stuff
      /*sensorVal = analogRead(distance_cm);
      ledBrightness = map(sensorVal, 0, 1186, 0, 255);
       analogWrite(LED_PIN, ledBrightness);*/
 

      if(distance_cm < DISTANCE_THRESHOLD)
        digitalWrite(LED_PIN, HIGH); // turn on LED
      else
        digitalWrite(LED_PIN, LOW);  // turn off LED
  
      // print the value to Serial Monitor
      Serial.print("distance: ");
      Serial.print(distance_cm);
      Serial.println(" cm");
  } else {
      Serial.println("button is released");
    }
  }
  delay(500);
  lastButtonState = currentButtonState;
}

  
 
//  delay(500);
//button first test
  //lastButtonState = currentButtonState;
  //currentButtonState = digitalRead(BUTTON_PIN);
  //erial.println(lastButtonState);
  //Serial.println(currentButtonState);
//  if(lastButtonState == HIGH && currentButtonState == LOW){
//    }
// //
//}