// Program for esp32 as bluetooth buffer
// created by Jans Hendry
// Universitas Gadjah Mada, Indonesia
// Kamakura Node, Japan
// fab academy MIT - 2022

// directive bluetooth serial
#include "BluetoothSerial.h"
BluetoothSerial SerialBT; // create an object

// variables
long dur;
long dist;
const int echoPin = 2; // echo pin
const int trigPin = 4; // trigger pin
const int toat = 15; // signal to attiny1614 as MOTOR
const int toat2 = 21; // signal to attiny1614 as LED
char vup = '1'; // check whether signal UP is active
char vdo = '0'; //
char vss = '2'; // get distance
char lon = '3'; // led on
char loff = '4'; // led off
char sign;

void setup() {
  Serial.begin(115200); // start serial esp32
  SerialBT.begin("ESP32 - Jans"); //Bluetooth device name

  // set pin as output
  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(toat, OUTPUT);
  digitalWrite(toat, LOW);
  pinMode(toat2, OUTPUT);
  digitalWrite(toat2, LOW);
  
  delay(500); // take a breath
}

void loop() {
  
  // check whether serial bluetooth is also available
  if (SerialBT.available()) {

    // read from bluetooth serial
    sign = (char)SerialBT.read();

    // motor signal
    if (sign == vup){
      digitalWrite(toat, HIGH);
      Serial.println(sign);
      delay(20);
    }
    else if (sign == vdo){
      digitalWrite(toat, LOW);
      Serial.println(sign);
      delay(20);
    }

    // LED signal
    if (sign == lon){
      digitalWrite(toat2, HIGH);
      Serial.println(sign);
      delay(20);
    }
    else if (sign == loff){
      digitalWrite(toat2, LOW);
      Serial.println(sign);
      delay(20);
    }

    // Request for distance sensor
    if (sign == vss){
      digitalWrite(trigPin, LOW);
      delayMicroseconds(2);
      
      digitalWrite(trigPin, HIGH);
      delayMicroseconds(10);
      
      digitalWrite(trigPin, LOW);
  
      // get the distance
      dur = pulseIn(echoPin, HIGH);
      dist = dur * 0.034/2;
      
      SerialBT.write(dist); // send via serial      
    }
  }
}