AZ Mandible Arduino Firmware

/*
AZ Mandible – Prototype Firmware v1.0
-------------------------------------
Hardware:
- Piezo (27mm) → 1M bias → Op-amp → A0
- Bone conduction transducer (TT25-8) via PAM8403 → D9 (PWM)
- Arduino Nano

Function:
- Detects intentional jaw movement peaks
- Simple classification:
1 clear peak → YES
2 quick peaks → NO
- Private bone-conduction feedback
*/

const int PIEZO_PIN = A0;
const int FEEDBACK_PIN = 9; // PWM to PAM8403 / transducer

// ===== TUNABLE VALUES =====
int threshold = 80; // Start here, adjust with Serial Plotter
const int DEBOUNCE_MS = 80;
const int WINDOW_MS = 600; // Time window to count peaks
const int MIN_PEAK_GAP = 120; // Minimum time between peaks

// ===== STATE =====
int peakCount = 0;
unsigned long lastPeakTime = 0;
unsigned long windowStart = 0;
bool inWindow = false;

void setup() {
Serial.begin(115200);
pinMode(FEEDBACK_PIN, OUTPUT);
analogWrite(FEEDBACK_PIN, 0);

Serial.println("AZ Mandible v1.0 ready");
Serial.println("1 peak = YES | 2 peaks = NO");
Serial.println("Open Serial Plotter to tune threshold");
}

void loop() {
int value = analogRead(PIEZO_PIN);

// Debug output for Serial Plotter
Serial.println(value);

unsigned long now = millis();

// Peak detection
if (value > threshold) {
if (now - lastPeakTime > MIN_PEAK_GAP) {
// Valid new peak
if (!inWindow) {
inWindow = true;
windowStart = now;
peakCount = 1;
} else {
peakCount++;
}
lastPeakTime = now;
}
}

// Window timeout → classify
if (inWindow && (now - windowStart > WINDOW_MS)) {
classify(peakCount);
peakCount = 0;
inWindow = false;
}

delay(5); // small loop delay
}

void classify(int peaks) {
if (peaks == 1) {
Serial.println("→ YES");
playFeedback(1); // single tone
}
else if (peaks >= 2) {
Serial.println("→ NO");
playFeedback(2); // double tone
}
}

void playFeedback(int type) {
if (type == 1) {
// YES – single medium beep
tone(FEEDBACK_PIN, 600, 120);
delay(140);
}
else if (type == 2) {
// NO – two short beeps
tone(FEEDBACK_PIN, 400, 80);
delay(120);
tone(FEEDBACK_PIN, 400, 80);
delay(100);
}
analogWrite(FEEDBACK_PIN, 0);
}

Aziel Eliab
research, hardware, legal
AZ Mandible Arduino Firmware
Aziel, mandible, corpus