// ─────────────────────────────────────────────────────────────────────────────
// A3144 Hall Effect Sensor — Serial Monitor Test
// XIAO ESP32-S3
//
//  A3144 VCC  →  5V
//  A3144 GND  →  GND
//  A3144 OUT  →  GPIO8 (D9) + 10kΩ pullup to 3.3V
// ─────────────────────────────────────────────────────────────────────────────

#define HALL_PIN      8       // GPIO8 — digital input
#define DEBOUNCE_MS   5       // ignore re-triggers within 5ms

volatile bool     pulseFlag    = false;
volatile uint32_t lastPulseUs  = 0;

unsigned long lastPrintTime    = 0;
unsigned long lastPulseTime    = 0;
int           pulseCount       = 0;
float         rpm              = 0.0;

// ── Interrupt — fires on each magnet passing ──────────────────────────────────

void IRAM_ATTR onPulse() {
  uint32_t now = micros();
  if (now - lastPulseUs > (DEBOUNCE_MS * 1000)) {
    lastPulseUs = now;
    pulseFlag   = true;
  }
}

// ─────────────────────────────────────────────────────────────────────────────

void setup() {
  Serial.begin(115200);
  pinMode(HALL_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(HALL_PIN), onPulse, FALLING);
  delay(500);
  Serial.println("A3144 Hall Effect Sensor Test");
  Serial.println("─────────────────────────────");
  Serial.println("Pulses/sec | RPM (10 magnets) | Status");
}

void loop() {
  unsigned long now = millis();

  // Handle pulse flag from ISR
  if (pulseFlag) {
    pulseFlag     = false;
    pulseCount++;
    lastPulseTime = now;
  }

  // Print every 500ms
  if (now - lastPrintTime >= 500) {
    lastPrintTime = now;

    // RPM = (pulses per second / magnets) * 60
    float pulsesPerSec = pulseCount * 2.0;   // 500ms window × 2
    rpm = (pulsesPerSec / 10.0) * 60.0;      // 10 magnets per revolution

    // Dial status
    bool dialMoving = (now - lastPulseTime) < 300;  // 300ms timeout
    String status = dialMoving ? "MOVING" : "STILL";

    Serial.print("Pulses/s: ");
    Serial.print(pulsesPerSec, 1);
    Serial.print("  \tRPM: ");
    Serial.print(rpm, 1);
    Serial.print("  \tStatus: ");
    Serial.println(status);

    pulseCount = 0;  // reset count for next window
  }
}