#define ECHO_PIN 2
#define TRIG_PIN 3
#define BUZZER_PIN 4
#define CLK_PIN   13
#define DATA_PIN  11
#define CS_PIN    10

bool stop = false;

#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

const uint16_t WAIT_TIME = 1000;

// Define the number of devices we have in the chain and the hardware interface
// NOTE: These pin numbers will probably not work with your hardware and may
// need to be adapted
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
#define MAX_DEVICES 4



// Hardware SPI connection
MD_Parola P = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
// Arbitrary output pins
// MD_Parola P = MD_Parola(HARDWARE_TYPE, DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);

void setup(){
  P.begin();
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(TRIG_PIN, LOW);
}

void loop(){

  int distanza;

  for(int i=0; i<10; i++){
    distanza += getDistanza();
  }

  distanza = distanza/10;
  Serial.println("Distanza: " + String(distanza) + "cm");


  if(distanza<=20){
    P.print("  STOP");
    if(stop==false){

      for(int i=0; i<10; i++){
        tone(BUZZER_PIN, 1500, 500);
        delay(1000);
      }

    }

    stop=true;

  }else{
     stop=false;
     P.print(String(distanza) + " cm");
  }

  Serial.println("Distanza: " + String(distanza) + "cm");
  delay(200);
}

int getDistanza(){
    int distanza;
  unsigned long tempo;

    digitalWrite(TRIG_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG_PIN, LOW);

    tempo = pulseIn(ECHO_PIN, HIGH);
    distanza = (0.033765 * tempo/2);
    delayMicroseconds(10);

  return distanza;
}