/* * VAULT — RFID Combination Lock with Temperature-Triggered Hold-Open * - Scan an RFID card to begin. Enter a 4-digit code using the two buttons * (cycle changes the digit, confirm locks it in). Correct code opens the * servo latch. The vault then stays open until the DHT11 senses the * temperature rise 5C above what it was at the moment of unlock, at * which point it automatically re-locks. * - A sudden temperature/humidity jump while locked/entering code is * treated as tampering and triggers an escalating lockout, same as * repeated wrong codes. * - The passive buzzer plays a distinct low buzz on any failure (wrong * code or tamper lockout), separate from the short beeps used for * normal button presses / successful unlock. * - The LCD's bottom-right corner always shows the live temperature. * * TESTING CODES (Serial Monitor, 9600 baud): * - Type "scan" to simulate an RFID card scan. * - Type "temp " (e.g. "temp 24.5") to override the live temp * reading. * CODE IS 1337 */ #include #include #include #include #include #include #include #include // ---------- Pin map ---------- #define RFID_SS_PIN 10 #define RFID_RST_PIN 9 #define RTC_CLK_PIN 3 #define RTC_DAT_PIN 2 #define RTC_RST_PIN 6 #define DHT_PIN A0 #define SERVO_PIN 8 #define BTN_CYCLE A1 #define BTN_CONFIRM A2 #define BUZZER_PIN A3 // ---------- Objects ---------- MFRC522 rfid(RFID_SS_PIN, RFID_RST_PIN); LiquidCrystal_I2C lcd(0x27, 16, 2); ThreeWire rtcWire(RTC_DAT_PIN, RTC_CLK_PIN, RTC_RST_PIN); RtcDS1302 rtc(rtcWire); DHT dht(DHT_PIN, DHT11); Servo latch; // ---------- State machine ---------- enum State { LOCKED, AUTHENTICATING, ENTERING_CODE, UNLOCKING, UNLOCKED, LOCKOUT }; State state = LOCKED; // ---------- Secret code ---------- const int CODE_LENGTH = 4; int secretCode[CODE_LENGTH] = {1, 3, 3, 7}; int enteredCode[CODE_LENGTH]; int codeIndex = 0; int currentDigit = 0; // ---------- Timing (all non-blocking) ---------- unsigned long lastDebounceCycle = 0; unsigned long lastDebounceConfirm = 0; const unsigned long DEBOUNCE_MS = 180; unsigned long confirmPressStart = 0; bool confirmHeld = false; const unsigned long LONG_PRESS_MS = 2000; unsigned long stateEnteredAt = 0; unsigned long lastTamperCheck = 0; const unsigned long TAMPER_CHECK_INTERVAL = 2000; unsigned long lockoutUntil = 0; int failedAttempts = 0; // ---------- Tamper baseline ---------- float baselineTemp = NAN; float baselineHumidity = NAN; const float TAMPER_TEMP_DELTA = 4.0; const float TAMPER_HUMIDITY_DELTA = 15.0; // ---------- Live temperature (shown on screen + used for unlock-hold logic) ---------- float currentTemp = NAN; float tempAtUnlock = NAN; const float UNLOCK_HOLD_TEMP_RISE = 5.0; // vault re-locks once temp rises this many degrees above tempAtUnlock void setup() { Serial.begin(9600); pinMode(BTN_CYCLE, INPUT_PULLUP); pinMode(BTN_CONFIRM, INPUT_PULLUP); pinMode(BUZZER_PIN, OUTPUT); SPI.begin(); rfid.PCD_Init(); Wire.begin(); lcd.init(); lcd.backlight(); rtc.Begin(); if (!rtc.IsDateTimeValid()) { RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__); rtc.SetDateTime(compiled); } if (rtc.GetIsWriteProtected()) { rtc.SetIsWriteProtected(false); } if (!rtc.GetIsRunning()) { rtc.SetIsRunning(true); } dht.begin(); latch.attach(SERVO_PIN); latch.write(0); // locked position delay(1500); baselineTemp = dht.readTemperature(); baselineHumidity = dht.readHumidity(); currentTemp = baselineTemp; showLockedScreen(); } void loop() { unsigned long now = millis(); checkTamper(now); checkLongPressReset(now); handleSerialTestCommands(); drawTempCorner(); switch (state) { case LOCKED: handleLocked(); break; case AUTHENTICATING: handleAuthenticating(now); break; case ENTERING_CODE: handleEnteringCode(now); break; case UNLOCKING: handleUnlocking(now); break; case UNLOCKED: handleUnlocked(now); break; case LOCKOUT: handleLockout(now); break; } } // ---------------- Serial testing commands ---------------- void handleSerialTestCommands() { if (!Serial.available()) return; String cmd = Serial.readStringUntil('\n'); cmd.trim(); if (cmd.equalsIgnoreCase("scan") && state == LOCKED) { Serial.println("[TEST] Simulated card scan"); beep(1); changeState(AUTHENTICATING); } else if (cmd.startsWith("temp ")) { float simTemp = cmd.substring(5).toFloat(); currentTemp = simTemp; if (isnan(baselineTemp)) baselineTemp = simTemp; Serial.print("[TEST] Simulated temp set to: "); Serial.println(currentTemp); } } // ---------------- State handlers ---------------- void handleLocked() { if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()) { Serial.println("Card detected!"); beep(1); rfid.PICC_HaltA(); changeState(AUTHENTICATING); } } void handleAuthenticating(unsigned long now) { if (now - stateEnteredAt > 800) { codeIndex = 0; currentDigit = 0; changeState(ENTERING_CODE); } } void handleEnteringCode(unsigned long now) { lcd.setCursor(0, 1); lcd.print("D"); lcd.print(codeIndex + 1); lcd.print(":"); lcd.print(currentDigit); lcd.print(" "); if (buttonPressed(BTN_CYCLE, lastDebounceCycle, now)) { currentDigit = (currentDigit + 1) % 10; } // short-press confirm = confirm digit (long-press elsewhere = reset) if (digitalRead(BTN_CONFIRM) == LOW) { if (!confirmHeld && (now - lastDebounceConfirm) > DEBOUNCE_MS) { lastDebounceConfirm = now; enteredCode[codeIndex] = currentDigit; codeIndex++; currentDigit = 0; beep(1); if (codeIndex >= CODE_LENGTH) { if (checkCode()) { changeState(UNLOCKING); } else { registerFailedAttempt(now); } } } } } void handleUnlocking(unsigned long now) { latch.write(90); // open position logUnlockEvent(); beep(3); tempAtUnlock = currentTemp; // vault stays open until temp rises 5C above this changeState(UNLOCKED); } void handleUnlocked(unsigned long now) { lcd.setCursor(0, 1); lcd.print("Open "); bool tempRoseEnough = !isnan(currentTemp) && !isnan(tempAtUnlock) && (currentTemp - tempAtUnlock >= UNLOCK_HOLD_TEMP_RISE); if (tempRoseEnough) { latch.write(0); failedAttempts = 0; changeState(LOCKED); } } void handleLockout(unsigned long now) { unsigned long remaining = (lockoutUntil > now) ? (lockoutUntil - now) / 1000 : 0; lcd.setCursor(0, 1); lcd.print("Wait "); lcd.print(remaining); lcd.print("s "); if (now >= lockoutUntil) { changeState(LOCKED); } } // ---------------- Reset via long-press ---------------- void checkLongPressReset(unsigned long now) { if (digitalRead(BTN_CONFIRM) == LOW) { if (confirmPressStart == 0) { confirmPressStart = now; } else if (!confirmHeld && (now - confirmPressStart) > LONG_PRESS_MS) { confirmHeld = true; beep(2); changeState(LOCKED); } } else { confirmPressStart = 0; confirmHeld = false; } } // ---------------- Helpers ---------------- bool checkCode() { for (int i = 0; i < CODE_LENGTH; i++) { if (enteredCode[i] != secretCode[i]) return false; } return true; } void registerFailedAttempt(unsigned long now) { failedAttempts++; failBeep(); unsigned long lockoutSeconds = 5UL << (failedAttempts - 1 > 4 ? 4 : failedAttempts - 1); lockoutUntil = now + lockoutSeconds * 1000UL; changeState(LOCKOUT); } void changeState(State newState) { state = newState; stateEnteredAt = millis(); switch (newState) { case LOCKED: showLockedScreen(); break; case AUTHENTICATING: lcd.clear(); lcd.setCursor(0, 0); lcd.print("Card detected..."); break; case ENTERING_CODE: lcd.clear(); lcd.setCursor(0, 0); lcd.print("Enter code:"); break; case UNLOCKING: lcd.clear(); lcd.setCursor(0, 0); lcd.print("Unlocking..."); break; case UNLOCKED: lcd.clear(); lcd.setCursor(0, 0); lcd.print("VAULT OPEN"); break; case LOCKOUT: lcd.clear(); lcd.setCursor(0, 0); lcd.print("LOCKED OUT"); break; } } bool buttonPressed(int pin, unsigned long &lastDebounce, unsigned long now) { if (digitalRead(pin) == LOW && (now - lastDebounce) > DEBOUNCE_MS) { lastDebounce = now; return true; } return false; } void beep(int times) { tone(BUZZER_PIN, 1200, 80 * times); } void failBeep() { tone(BUZZER_PIN, 300, 500); } void showLockedScreen() { lcd.clear(); lcd.setCursor(0, 0); lcd.print("VAULT: Scan card"); } void logUnlockEvent() { RtcDateTime t = rtc.GetDateTime(); Serial.print("Unlock at "); Serial.print(t.Year()); Serial.print('-'); Serial.print(t.Month()); Serial.print('-'); Serial.print(t.Day()); Serial.print(' '); Serial.print(t.Hour()); Serial.print(':'); Serial.print(t.Minute()); Serial.print(':'); Serial.println(t.Second()); } void checkTamper(unsigned long now) { if (now - lastTamperCheck < TAMPER_CHECK_INTERVAL) return; lastTamperCheck = now; float temp = dht.readTemperature(); float hum = dht.readHumidity(); if (isnan(temp) || isnan(hum)) return; currentTemp = temp; bool tempJump = !isnan(baselineTemp) && fabs(temp - baselineTemp) > TAMPER_TEMP_DELTA; bool humJump = !isnan(baselineHumidity) && fabs(hum - baselineHumidity) > TAMPER_HUMIDITY_DELTA; if ((tempJump || humJump) && state != LOCKOUT) { failBeep(); failedAttempts = max(failedAttempts, 2); lockoutUntil = now + 15000UL; changeState(LOCKOUT); } } // ---------------- Temperature readout (bottom-right of LCD) ---------------- void drawTempCorner() { lcd.setCursor(11, 1); if (isnan(currentTemp)) { lcd.print(" --C "); } else { char buf[6]; dtostrf(currentTemp, 4, 1, buf); // e.g. "24.5" lcd.print(buf); lcd.print("C"); } }