// Author : Quentin BENETHUILLERE
// Date of creation : 2021/04/09
// Last modification : 2021/04/21

/*
 * Program function(s):
This programs aims at testing capacitive sensors (in my case simple squares cut in copper sheet). In my situation 3 capacitive sensors are available.
- as long as left capacitive sensor is touched : red LED turns ON.
- as long as middle capacitive sensor is touched : green LED turns ON.
- as long as right capacitive sensor is touched : blue LED turns ON.
- Otherwise LEDs are OFF.
 */

// -----------
// LIBRAIRIES
// -----------

#include <CapacitiveSensor.h>

// -------------------------
// DECLARATION OF DEFINES 
// -------------------------

// -------------------------
// DECLARATION OF VARIABLES 
// -------------------------

// ------------------------------------------------
// Adjustable variables (program main parameters)
// ------------------------------------------------
const int DETECTION_THRESHOLD = 500; // Threshold above which a touch on a capacitive sensor is considered. Value to be adjusted based on the circuit, and capacitive sensors used.
const int CAPACITIVE_MEASUREMENT = 30; // Determines the resolution for the capacitive touch measurement. 30 used in the examples I found.
const byte nb_sensors=3; // Number of capacitive sensors.

// ------------------------------------------------
// PIN connections
// ------------------------------------------------

//* Analogic PIN :

//* Digital PIN :
const byte PIN_red_LED = 6; // Red LED
const byte PIN_green_LED = 7; // Green LED
const byte PIN_blue_LED = 8; // Blue LED
const byte PIN_sensor_emitter = 2; // PIN that sends the signal to measure feedback from capacitive sensors.
const byte PIN_sensor_1 = 3; // PIN that measures capacitive sensor 1.
const byte PIN_sensor_2 = 4; // PIN that measures capacitive sensor 2.
const byte PIN_sensor_3 = 5; // PIN that measures capacitive sensor 3.

// ------------------------------------------------
// Other variables
// ------------------------------------------------
byte sequence_position = 0; // variable to determine in which position of the sequence a touch should be registered.
long total=0; // variable to measure the output from a capacitive sensor.

// -------------------------
// DECLARATION OF OBJECTS 
// -------------------------

// In this Arduino example, 3 capacitive sensors are used : 1 is the left sensor, 2 is the middle sensor, 3 is the right sensor.

CapacitiveSensor   cs_1 = CapacitiveSensor(PIN_sensor_emitter,PIN_sensor_1);        // Capacitive Sensor 1
CapacitiveSensor   cs_2 = CapacitiveSensor(PIN_sensor_emitter,PIN_sensor_2);        // Capacitive Sensor 2
CapacitiveSensor   cs_3 = CapacitiveSensor(PIN_sensor_emitter,PIN_sensor_3);        // Capacitive Sensor 3
CapacitiveSensor cs_list[nb_sensors] = {cs_1, cs_2, cs_3}; // list of the capacitive sensors declared above, for code optimization.

// -------------------------
// INITIALIZATION 
// -------------------------

void setup()                    
{

// ------------------------------------------------
// Communication
// ------------------------------------------------

   Serial.begin(9600);

// ------------------------------------------------
// Objects
// ------------------------------------------------

// ------------------------------------------------
// Input / Output
// ------------------------------------------------

   pinMode(PIN_red_LED,OUTPUT);
   pinMode(PIN_green_LED,OUTPUT);
   pinMode(PIN_blue_LED,OUTPUT);

// ------------------------------------------------
// PIN initial states
// ------------------------------------------------

   digitalWrite(PIN_red_LED,LOW);
   digitalWrite(PIN_green_LED,LOW); 
   digitalWrite(PIN_blue_LED,LOW);

// ------------------------------------------------
// Other
// ------------------------------------------------
    
} // end setup function

void loop()                    
{

  for (byte i=0; i<nb_sensors; i++){
    total = cs_list[i].capacitiveSensor(CAPACITIVE_MEASUREMENT);
    
    /* For debug purposes, and read what value is returned by each sensor uncomment those lines : 
    Serial.print(i);
    Serial.print(" : ");
    Serial.println(total);
    */
    switch(i){
      case 0:
        if (total>=DETECTION_THRESHOLD){
          digitalWrite(PIN_red_LED,HIGH);
        } // end if
        else{
          digitalWrite(PIN_red_LED,LOW);                  
        } // end else
        break;
      case 1:
        if (total>=DETECTION_THRESHOLD){
          digitalWrite(PIN_green_LED,HIGH);
        } // end if
        else{
          digitalWrite(PIN_green_LED,LOW);                  
        } // end else
        break;
      case 2:
        if (total>=DETECTION_THRESHOLD){
          digitalWrite(PIN_blue_LED,HIGH);
        } // end if
        else{
          digitalWrite(PIN_blue_LED,LOW);                  
        } // end else
        break;
    } // end switch
  } // end for
  
} // end loop function