/*
 * Touch Sensor Sargam Instrument - Barduino
 * Fab Academy 2026 - Week 4: Embedded Programming
 * Shivangi Pande | Fab Lab Barcelona
 *
 * Maps 6 capacitative touch pads on the Barduino
 * to Hindustani swaras (Sa Re Ga Ma Pa Ni).
 * Touch a pad → LED lights up + buzzer plays the note.
 *
 * Uses adaptive baseline calibration:
 * On boot, reads each sensor's "resting" value.
 * A touch is detected when the reading exceeds
 * baseline + threshold (50000).
 * When no touch is detected, baselines slowly drift
 * with an exponential moving average to handle
 * temperature/humidity changes.
 *
 * Pin mapping:
 *   Pin 1 → Ni  (491 Hz)
 *   Pin 2 → Pa  (392 Hz)
 *   Pin 4 → Sa  (262 Hz)
 *   Pin 5 → Re  (294 Hz)
 *   Pin 6 → Ga  (327 Hz)
 *   Pin 7 → Ma  (349 Hz)
 */

#define LED_PIN 48
#define BUZZER_PIN 46

// Touch pins
#define T_NI 1
#define T_PA 2
#define T_SA 4
#define T_RE 5
#define T_GA 6
#define T_MA 7

// Frequencies
int NI = 491;
int PA = 392;
int SA = 262;
int RE = 294;
int GA = 327;
int MA = 349;

// Baselines
int bNI, bPA, bSA, bRE, bGA, bMA;
int threshold = 50000;

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  delay(500); // IMPORTANT: no touching now

  bNI = touchRead(T_NI);
  bPA = touchRead(T_PA);
  bSA = touchRead(T_SA);
  bRE = touchRead(T_RE);
  bGA = touchRead(T_GA);
  bMA = touchRead(T_MA);
}

void loop() {
  int vNI = touchRead(T_NI);
  int vPA = touchRead(T_PA);
  int vSA = touchRead(T_SA);
  int vRE = touchRead(T_RE);
  int vGA = touchRead(T_GA);
  int vMA = touchRead(T_MA);

  if (vNI > bNI + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, NI);
  }
  else if (vPA > bPA + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, PA);
  }
  else if (vSA > bSA + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, SA);
  }
  else if (vRE > bRE + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, RE);
  }
  else if (vGA > bGA + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, GA);
  }
  else if (vMA > bMA + threshold) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, MA);
  }
  else {
    digitalWrite(LED_PIN, LOW);
    noTone(BUZZER_PIN);

    // adaptive baseline (no touch only)
    bNI = (bNI * 9 + vNI) / 10;
    bPA = (bPA * 9 + vPA) / 10;
    bSA = (bSA * 9 + vSA) / 10;
    bRE = (bRE * 9 + vRE) / 10;
    bGA = (bGA * 9 + vGA) / 10;
    bMA = (bMA * 9 + vMA) / 10;
  }

  delay(20);
}