Arduino program for Bluebird Box Door

bluebird_box_door.c

/*
  Bird box gate (servo) controller - Arduino Nano

  RF receiver is in MOMENTARY mode and drives a relay contact:
    Relay COM -> GND
    Relay NO  -> D2

  We use D2 with INPUT_PULLUP:
    - D2 reads HIGH normally
    - D2 reads LOW while the relay is energized (button held)

  Servo:
    - Signal on D9
    - Servo powered from a solid external 5V rail

  Behavior:
    - On startup: command servo to 550 µs
    - Each button press toggles servo between 550 µs and 2360 µs
*/

#include <Servo.h>

const int SERVO_PIN = 9;
const int RF_PIN    = 2;

// Pulse widths in microseconds
const int PULSE_CLOSED = 550;
const int PULSE_OPEN   = 2360;

// Smooth motion tuning
const int STEP_US = 5;              // smaller = smoother, slower; larger = faster
const int STEP_DELAY_MS = 10;       // delay per step
int currentPulse = PULSE_CLOSED;    // track current command pulse width

// Debounce / lockout
const unsigned long DEBOUNCE_MS = 30;       // relay contacts are pretty clean, but keep small debounce
const unsigned long PRESS_LOCKOUT_MS = 250; // prevents multiple toggles if button is held

Servo gateServo;

bool isOpen = false;
unsigned long lastToggleTime = 0;

void moveServoSmoothTo(int targetPulse) {
  // Clamp to a reasonable range, just to be safe
  // Adjust if you truly want to allow wider pulses.
  if (targetPulse < 500) targetPulse = 500;
  if (targetPulse > 2500) targetPulse = 2500;

  int startPulse = currentPulse;
  int dir = (targetPulse > startPulse) ? +1 : -1;

  for (int p = startPulse; p != targetPulse; p += dir * STEP_US) {
    gateServo.writeMicroseconds(p);
    currentPulse = p;
    delay(STEP_DELAY_MS);
  }

  // Ensure final value is commanded exactly
  gateServo.writeMicroseconds(targetPulse);
  currentPulse = targetPulse;
}

void goClosed() {
  moveServoSmoothTo(PULSE_CLOSED);
  isOpen = false;
}

void goOpen() {
  moveServoSmoothTo(PULSE_OPEN);
  isOpen = true;
}

void toggleGate() {
  if (isOpen) goClosed();
  else        goOpen();
}

void setup() {
  pinMode(RF_PIN, INPUT_PULLUP);

  gateServo.attach(SERVO_PIN);

  // Startup position
  goClosed();
  delay(500);
}

void loop() {
  // Momentary relay closes to GND when pressed
  static bool lastStable = HIGH;
  static bool lastReading = HIGH;
  static unsigned long lastDebounceTime = 0;

  bool reading = digitalRead(RF_PIN);

  // Debounce: detect stable change
  if (reading != lastReading) {
    lastDebounceTime = millis();
    lastReading = reading;
  }

  if (millis() - lastDebounceTime > DEBOUNCE_MS) {
    if (reading != lastStable) {
      lastStable = reading;

      // Treat HIGH->LOW transition as a button press event
      if (lastStable == LOW) {
        if (millis() - lastToggleTime > PRESS_LOCKOUT_MS) {
          lastToggleTime = millis();
          toggleGate();
        }
      }
    }
  }
}