feat: X3 gyroscope-based tilt page turning via QMI8658 IMU (#1636)

Co-authored-by: justinian <juicecutlus@gmail.com>
Co-authored-by: Vincent Politzer <vincent@skipwithjoy.com>

lib/I18n/translations/belarusian.yaml

@@ -290,3 +290,4 @@ STR_NO_FOOTNOTES: "На гэтай старонцы няма зносак"
 STR_LINK: "[спасылка]"
 STR_AUTO_TURN_ENABLED: "Аўтаперагортванне: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Аўтаперагортванне (старонак за хвіліну)"
+STR_TILT_PAGE_TURN: "Перагортванне нахілам"

lib/I18n/translations/catalan.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[enllaç]"
 STR_SCREENSHOT_BUTTON: "Fes una captura de pantalla"
 STR_AUTO_TURN_ENABLED: "Passar automàtic activat: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Passar automàtic (pàgines per minut)"
+STR_TILT_PAGE_TURN: "Pas de pàgina per inclinació"

lib/I18n/translations/czech.yaml

@@ -262,3 +262,4 @@ STR_BOOK_S_STYLE: "Styl knihy"
 STR_EMBEDDED_STYLE: "Vložený styl"
 STR_OPDS_SERVER_URL: "URL serveru OPDS"
 STR_SCREENSHOT_BUTTON: "Udělat snímek obrazovky"
+STR_TILT_PAGE_TURN: "Otáčení stránek nakloněním"

lib/I18n/translations/danish.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Tag skærmbillede"
 STR_AUTO_TURN_ENABLED: "Automatisk sidevendning aktiveret: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Automatisk vending (sider per minut)"
+STR_TILT_PAGE_TURN: "Vip for at vende side"

lib/I18n/translations/dutch.yaml

@@ -289,4 +289,5 @@ STR_NO_FOOTNOTES: "Geen voetnoten op deze pagina"
 STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Screenshot maken"
 STR_AUTO_TURN_ENABLED: "Automatisch omslaan ingeschakeld: "
-STR_AUTO_TURN_PAGES_PER_MIN: "Autom. omslaan (pagina's per minuut)"
+STR_AUTO_TURN_PAGES_PER_MIN: "Autom. omslaan (pagina's per minuut)"
+STR_TILT_PAGE_TURN: "Kantel om te bladeren"

lib/I18n/translations/english.yaml

@@ -305,6 +305,7 @@ STR_CRASH_TITLE: "System Crash"
 STR_CRASH_DESCRIPTION: "A detailed report was saved to crash_report.txt. Please include this file in your bug report."
 STR_CRASH_REASON: "Crash reason:"
 STR_CRASH_NO_REASON: "(No reason was recorded)"
+STR_TILT_PAGE_TURN: "Tilt Page Turn"
 STR_KB_HINT_MOVE_CURSOR: "Press LEFT or RIGHT to move cursor"
 STR_KB_HINT_RETURN_CURSOR: "Press LEFT to return to cursor position"
 STR_KB_HINT_HIDE_PASSWORD: "Hold RIGHT then press [***] to hide password"

lib/I18n/translations/finnish.yaml

@@ -260,3 +260,4 @@ STR_BOOK_S_STYLE: "Kirjan tyyli"
 STR_EMBEDDED_STYLE: "Upotettu tyyli"
 STR_OPDS_SERVER_URL: "OPDS-palvelimen osoite"
 STR_SCREENSHOT_BUTTON: "Ota kuvakaappaus"
+STR_TILT_PAGE_TURN: "Sivunkääntö kallistamalla"

lib/I18n/translations/french.yaml

@@ -291,3 +291,4 @@ STR_LINK: "[lien]"
 STR_SCREENSHOT_BUTTON: "Capture d'écran"
 STR_AUTO_TURN_ENABLED: "Tourne-page auto : "
 STR_AUTO_TURN_PAGES_PER_MIN: "Tourne-page auto (pages par minute)"
+STR_TILT_PAGE_TURN: "Tourner par inclinaison"

lib/I18n/translations/german.yaml

@@ -321,3 +321,4 @@ STR_UPTIME: "Laufzeit"
 STR_CHARGING: "Lädt"
 STR_GATHERING_DATA: "Daten werden gesammelt..."
 STR_READING: "Lese..."
+STR_TILT_PAGE_TURN: "Neigung zum Blättern"

lib/I18n/translations/hungarian.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Képernyőkép készítése"
 STR_AUTO_TURN_ENABLED: "Automatikus lapozás bekapcsolva: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Automatikus lapozás (oldal/perc)"
+STR_TILT_PAGE_TURN: "Döntéses lapozás"

lib/I18n/translations/italian.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Screenshot"
 STR_AUTO_TURN_ENABLED: "Cambio pagina automatico: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Cambio pagina automatico (pag/min)"
+STR_TILT_PAGE_TURN: "Gira pagina con inclinazione"

lib/I18n/translations/kazakh.yaml

@@ -289,3 +289,4 @@ STR_LINK: "[сілтеме]"
 STR_SCREENSHOT_BUTTON: "Скриншот түсіру"
 STR_AUTO_TURN_ENABLED: "Автоматты бет аудару қосулы: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Автоматты бет аудару (минутына бет саны)"
+STR_TILT_PAGE_TURN: "Еңкейту арқылы бет аудару"

lib/I18n/translations/lithuanian.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[nuoroda]"
 STR_SCREENSHOT_BUTTON: "Ekrano nuotrauka"
 STR_AUTO_TURN_ENABLED: "Auto-vertimas: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Auto-vertimas (psl/min)"
+STR_TILT_PAGE_TURN: "Puslapio vertimas pakreipiant"

lib/I18n/translations/polish.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Zrób zrzut ekranu"
 STR_AUTO_TURN_ENABLED: "Auto-kartkowanie: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Auto-kartkowanie (str./min)"
+STR_TILT_PAGE_TURN: "Kartkowanie przechyłem"

lib/I18n/translations/portuguese.yaml

@@ -262,3 +262,4 @@ STR_BOOK_S_STYLE: "Estilo do livro"
 STR_EMBEDDED_STYLE: "Estilo embutido"
 STR_OPDS_SERVER_URL: "URL do servidor OPDS"
 STR_SCREENSHOT_BUTTON: "Capturar tela"
+STR_TILT_PAGE_TURN: "Virar página por inclinação"

lib/I18n/translations/romanian.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[link]"
 STR_SCREENSHOT_BUTTON: "Captură ecran"
 STR_AUTO_TURN_ENABLED: "Răsfoire automată: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Pagini pe minut"
+STR_TILT_PAGE_TURN: "Întoarcere pagină prin înclinare"

lib/I18n/translations/russian.yaml

@@ -291,6 +291,7 @@ STR_OPDS_SERVER_URL: "URL OPDS сервера"
 STR_SCREENSHOT_BUTTON: "Сделать снимок экрана"
 STR_AUTO_TURN_ENABLED: "Автоперелистывание: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Автоперелистывание (стр./мин)"
+STR_TILT_PAGE_TURN: "Перелистывание наклоном"
 STR_ADD_SERVER: "Добавить сервер"
 STR_SERVER_NAME: "Имя сервера"
 STR_NO_SERVERS: "Нет настроенных серверов OPDS"

lib/I18n/translations/slovenian.yaml

@@ -290,3 +290,4 @@ STR_LINK: "[povezava]"
 STR_SCREENSHOT_BUTTON: "Naredi posnetek zaslona"
 STR_AUTO_TURN_ENABLED: "Samodejno obračanje: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Samodejno obračanje (strani na minuto)"
+STR_TILT_PAGE_TURN: "Obračanje s priklonom"

lib/I18n/translations/spanish.yaml

@@ -289,5 +289,6 @@ STR_FOOTNOTES: "Pie de página"
 STR_NO_FOOTNOTES: "No hay notas al pie de esta página"
 STR_LINK: "[enlace]"
 STR_SCREENSHOT_BUTTON: "Tomar captura de pantalla"
+STR_TILT_PAGE_TURN: "Pasar página inclinando"
 STR_AUTO_TURN_ENABLED: "Avance activado: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Avance auto. (pág./min)"

lib/I18n/translations/swedish.yaml

@@ -305,6 +305,7 @@ STR_CRASH_TITLE: "Systemkrasch"
 STR_CRASH_DESCRIPTION: "En detaljerad rapport sparades till crash_report.txt. Vänligen inkludera den här filen i din felrapport."
 STR_CRASH_REASON: "Orsak till kraschen:"
 STR_CRASH_NO_REASON: "(Ingen orsak registrerades)"
+STR_TILT_PAGE_TURN: "Luta för att vända sida"
 STR_KB_HINT_MOVE_CURSOR: "Tryck VÄNSTER eller HÖGER för att flytta markören"
 STR_KB_HINT_RETURN_CURSOR: "Tryck VÄNSTER för att återgå till markörpositionen"
 STR_KB_HINT_HIDE_PASSWORD: "Håll HÖGER och tryck sedan på [***] för att dölja lösenordet"

lib/I18n/translations/turkish.yaml

@@ -290,3 +290,4 @@ STR_SCREENSHOT_BUTTON: "Ekran görüntüsü al"
 STR_SELECTED: "Seçili"
 STR_SHOW: "Göster"
 STR_TITLE: "Başlık"
+STR_TILT_PAGE_TURN: "Eğerek sayfa çevirme"

lib/I18n/translations/ukrainian.yaml

@@ -291,3 +291,4 @@ STR_LINK: "[посилання]"
 STR_SCREENSHOT_BUTTON: "Знімок екрана"
 STR_AUTO_TURN_ENABLED: "Автоперегортання увімк: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Автоперегортання (ст/хв)"
+STR_TILT_PAGE_TURN: "Перегортання нахилом"

lib/hal/HalTiltSensor.cpp

@@ -0,0 +1,234 @@
+#include "HalTiltSensor.h"
+
+#include <Logging.h>
+
+HalTiltSensor halTiltSensor;  // Singleton instance
+
+bool HalTiltSensor::writeReg(uint8_t reg, uint8_t val) const {
+  Wire.beginTransmission(_i2cAddr);
+  Wire.write(reg);
+  Wire.write(val);
+  return Wire.endTransmission() == 0;
+}
+
+bool HalTiltSensor::readReg(uint8_t reg, uint8_t* val) const {
+  Wire.beginTransmission(_i2cAddr);
+  Wire.write(reg);
+  if (Wire.endTransmission(false) != 0) {
+    return false;
+  }
+  Wire.requestFrom(_i2cAddr, (uint8_t)1);
+  if (Wire.available() < 1) {
+    return false;
+  }
+  *val = Wire.read();
+  return true;
+}
+
+bool HalTiltSensor::readGyro(float& gx, float& gy, float& gz) const {
+  Wire.beginTransmission(_i2cAddr);
+  Wire.write(REG_GX_L);  // Start reading at Gyro X Low
+  if (Wire.endTransmission(false) != 0) {
+    return false;
+  }
+
+  Wire.requestFrom(_i2cAddr, (uint8_t)6);
+  if (Wire.available() < 6) {
+    return false;
+  }
+
+  auto readInt16 = [&]() -> int16_t {
+    const uint8_t lo = Wire.read();
+    const uint8_t hi = Wire.read();
+    return static_cast<int16_t>((hi << 8) | lo);
+  };
+
+  // If Full Scale is ±512 dps, the scale factor is 32768 / 512 = 64 LSB/dps
+  constexpr float SCALE = 1.0f / 64.0f;
+  gx = readInt16() * SCALE;
+  gy = readInt16() * SCALE;
+  gz = readInt16() * SCALE;
+  return true;
+}
+
+void HalTiltSensor::begin() {
+  if (!gpio.deviceIsX3()) {
+    _available = false;
+    return;
+  }
+
+  // Try primary address, then alternate
+  uint8_t whoami = 0;
+  _i2cAddr = I2C_ADDR_QMI8658;
+  if (!readReg(QMI8658_WHO_AM_I_REG, &whoami) || whoami != QMI8658_WHO_AM_I_VALUE) {
+    _i2cAddr = I2C_ADDR_QMI8658_ALT;
+    if (!readReg(QMI8658_WHO_AM_I_REG, &whoami) || whoami != QMI8658_WHO_AM_I_VALUE) {
+      LOG_ERR("GYR", "QMI8658 IMU not found");
+      _available = false;
+      return;
+    }
+  }
+
+  LOG_INF("GYR", "QMI8658 IMU found at 0x%02X", _i2cAddr);
+
+  if (!writeReg(REG_CTRL7, CTRL7_DISABLE_ALL) || !writeReg(REG_CTRL3, CTRL3_FS_512DPS | CTRL3_ODR_28HZ) ||
+      !writeReg(REG_CTRL1, CTRL1_BASE | CTRL1_SENSOR_DISABLE)) {
+    LOG_ERR("GYR", "QMI8658 register configuration failed");
+    _available = false;
+    return;
+  }
+
+  _available = true;
+  _initMs = millis();
+  _lastPollMs = millis();
+  LOG_INF("GYR", "QMI8658 gyro initialized and put to sleep");
+}
+
+bool HalTiltSensor::wake() {
+  if (!_available) {
+    return false;
+  }
+
+  // Wait for init to complete before waking
+  if ((millis() - _initMs) < SLEEP_STABILIZE_MS) {
+    return false;
+  }
+
+  if (writeReg(REG_CTRL1, CTRL1_BASE) && writeReg(REG_CTRL7, CTRL7_GYRO_ENABLE)) {
+    _lastPollMs = millis();
+    _lastTiltMs = millis();
+    _wakeMs = millis();
+    LOG_INF("GYR", "QMI8658 woke up");
+    return true;
+  } else {
+    LOG_ERR("GYR", "Failed to wake QMI8658");
+    return false;
+  }
+}
+
+bool HalTiltSensor::deepSleep() {
+  if (!_available) {
+    return false;
+  }
+
+  if ((millis() - _wakeMs) < SLEEP_STABILIZE_MS) {
+    return false;
+  }
+
+  if (writeReg(REG_CTRL7, CTRL7_DISABLE_ALL) && writeReg(REG_CTRL1, CTRL1_BASE | CTRL1_SENSOR_DISABLE)) {
+    // Clear any residual state so it doesn't immediately trigger upon waking
+    clearPendingEvents();
+    _inTilt = false;
+    LOG_INF("GYR", "QMI8658 entered sleep mode");
+    return true;
+  } else {
+    LOG_ERR("GYR", "Failed to put QMI8658 to sleep");
+    return false;
+  }
+}
+
+void HalTiltSensor::update(const uint8_t mode, const uint8_t orientation, const bool inReader) {
+  if (!_available) {
+    return;
+  }
+
+  // State machine: wake up or sleep based on the enabled flag
+  if ((mode != CrossPointTiltPageTurn::TILT_OFF) && !_isAwake) {
+    _isAwake = wake();
+    return;
+  } else if ((mode == CrossPointTiltPageTurn::TILT_OFF) && _isAwake) {
+    _isAwake = !deepSleep();
+    return;
+  }
+
+  // If disabled, skip the rest of the polling logic and avoid unnecessary I2C traffic in non-reader activities
+  if ((mode == CrossPointTiltPageTurn::TILT_OFF) || !inReader) {
+    return;
+  }
+
+  const unsigned long now = millis();
+  // Stabilization: discard readings during gyro startup transient
+  if ((now - _wakeMs) < WAKE_STABILIZE_MS) {
+    return;
+  }
+
+  if ((now - _lastPollMs) < POLL_INTERVAL_MS) {
+    return;
+  }
+  _lastPollMs = now;
+
+  float gx, gy, gz;
+  if (!readGyro(gx, gy, gz)) {
+    return;
+  }
+
+  // Map the gyro axis to left/right tilt based on reader orientation.
+  // On the X3 PCB: X axis = left/right in portrait, Y axis = left/right in landscape.
+  float tiltAxis;
+  switch (orientation) {
+    case CrossPointOrientation::PORTRAIT:
+      tiltAxis = mode == CrossPointTiltPageTurn::TILT_INVERTED ? -gx : gx;
+      break;
+    case CrossPointOrientation::INVERTED:
+      tiltAxis = mode == CrossPointTiltPageTurn::TILT_INVERTED ? gx : -gx;
+      break;
+    case CrossPointOrientation::LANDSCAPE_CW:
+      tiltAxis = mode == CrossPointTiltPageTurn::TILT_INVERTED ? gy : -gy;
+      break;
+    case CrossPointOrientation::LANDSCAPE_CCW:
+      tiltAxis = mode == CrossPointTiltPageTurn::TILT_INVERTED ? -gy : gy;
+      break;
+    default:
+      tiltAxis = gx;
+      break;
+  }
+
+  if (_inTilt) {
+    // Wait for device to return to neutral before allowing next trigger
+    if (fabsf(tiltAxis) < NEUTRAL_RATE_DPS) {
+      _inTilt = false;
+    }
+  } else {
+    // Check for new tilt gesture (with cooldown)
+    if ((now - _lastTiltMs) >= COOLDOWN_MS) {
+      if (tiltAxis > RATE_THRESHOLD_DPS) {
+        _tiltForwardEvent = true;
+        _hadActivity = true;
+        _inTilt = true;
+        _lastTiltMs = now;
+        LOG_INF("GYR", "Forward Trigger=(%.1f) dps", tiltAxis);
+      } else if (tiltAxis < -RATE_THRESHOLD_DPS) {
+        _tiltBackEvent = true;
+        _hadActivity = true;
+        _inTilt = true;
+        _lastTiltMs = now;
+        LOG_INF("GYR", "Backward Trigger=(%.1f) dps", tiltAxis);
+      }
+    }
+  }
+}
+
+bool HalTiltSensor::wasTiltedForward() {
+  const bool val = _tiltForwardEvent;
+  _tiltForwardEvent = false;
+  return val;
+}
+
+bool HalTiltSensor::wasTiltedBack() {
+  const bool val = _tiltBackEvent;
+  _tiltBackEvent = false;
+  return val;
+}
+
+bool HalTiltSensor::hadActivity() {
+  const bool val = _hadActivity;
+  _hadActivity = false;
+  return val;
+}
+
+void HalTiltSensor::clearPendingEvents() {
+  _tiltForwardEvent = false;
+  _tiltBackEvent = false;
+  _hadActivity = false;
+  // Intentionally preserve _inTilt so a held tilt doesn't retrigger on next poll
+}

lib/hal/HalTiltSensor.h

@@ -0,0 +1,100 @@
+#pragma once
+
+#include <Arduino.h>
+#include <Wire.h>
+
+#include "HalGPIO.h"
+
+// TODO: Move enums into new header and share with CrossPointSettings.h
+namespace CrossPointOrientation {
+enum Value : uint8_t { PORTRAIT = 0, LANDSCAPE_CW = 1, INVERTED = 2, LANDSCAPE_CCW = 3 };
+}
+
+namespace CrossPointTiltPageTurn {
+enum Value : uint8_t { TILT_OFF = 0, TILT_NORMAL = 1, TILT_INVERTED = 2 };
+}
+
+class HalTiltSensor;
+extern HalTiltSensor halTiltSensor;  // Singleton
+
+class HalTiltSensor {
+  bool _available = false;
+  uint8_t _i2cAddr = 0;
+
+  // Tilt gesture state machine
+  bool _tiltForwardEvent = false;  // Consumed by wasTiltedForward()
+  bool _tiltBackEvent = false;     // Consumed by wasTiltedBack()
+  bool _hadActivity = false;       // Non-consuming flag for sleep timer
+  bool _inTilt = false;            // Currently tilted past threshold
+  bool _isAwake = false;           // Tracks power state
+  unsigned long _initMs = 0;       // Timestamp of sensor init
+  unsigned long _lastTiltMs = 0;   // Debounce / cooldown
+  unsigned long _wakeMs = 0;       // Timestamp of last wake() for stabilization
+
+  // Tuning constants
+  static constexpr float RATE_THRESHOLD_DPS = 270.0f;      // Deg/sec speed to trigger flick
+  static constexpr float NEUTRAL_RATE_DPS = 50.0f;         // Must stop moving below this rate before next trigger
+  static constexpr unsigned long COOLDOWN_MS = 600;        // Minimum ms between triggers
+  static constexpr unsigned long POLL_INTERVAL_MS = 50;    // 20 Hz polling
+  static constexpr unsigned long WAKE_STABILIZE_MS = 300;  // Ignore readings after wake
+  static constexpr unsigned long SLEEP_STABILIZE_MS = 15;  // Sleep turn on/off delay
+
+  mutable unsigned long _lastPollMs = 0;
+
+  // --- QMI8658 registers ---
+  static constexpr uint8_t REG_CTRL1 = 0x02;
+  static constexpr uint8_t REG_CTRL3 = 0x04;
+  static constexpr uint8_t REG_CTRL7 = 0x08;
+  static constexpr uint8_t REG_GX_L = 0x3B;
+
+  // --- Register Bit Flags ---
+
+  // REG_CTRL1 (0x02)
+  static constexpr uint8_t CTRL1_BIG_ENDIAN = (1 << 5);                     // 0x20: Default state (1 = Big Endian)
+  static constexpr uint8_t CTRL1_AUTO_INC = (1 << 6);                       // 0x40: Enable address auto-increment
+  static constexpr uint8_t CTRL1_SENSOR_DISABLE = (1 << 0);                 // 0x01: Power down sensor engine
+  static constexpr uint8_t CTRL1_BASE = CTRL1_AUTO_INC | CTRL1_BIG_ENDIAN;  // 0x60
+
+  // REG_CTRL3 (0x04) - Gyro Config
+  static constexpr uint8_t CTRL3_FS_512DPS = (0b101 << 4);  // Bits 6:4 = 101
+  static constexpr uint8_t CTRL3_ODR_28HZ = 0b1000;         // Bits 3:0 = 1000 (28.025 Hz)
+
+  // REG_CTRL7 (0x08) - Enable
+  static constexpr uint8_t CTRL7_DISABLE_ALL = 0x00;
+  static constexpr uint8_t CTRL7_GYRO_ENABLE = (1 << 1);  // Bit 1 = 1
+
+  bool writeReg(uint8_t reg, uint8_t val) const;
+  bool readReg(uint8_t reg, uint8_t* val) const;
+  bool readGyro(float& gx, float& gy, float& gz) const;
+
+ public:
+  // Call after gpio.begin() and powerManager.begin() (I2C already initialised for X3)
+  void begin();
+
+  // Enables the QMI8658 internal sensor engine
+  bool wake();
+
+  // Puts the QMI8658 into a low-power standby state
+  bool deepSleep();
+
+  // True if the QMI8658 IMU is present on this device
+  bool isAvailable() const { return _available; }
+
+  // Poll the accelerometer and update tilt gesture state.
+  void update(const uint8_t mode, const uint8_t orientation, const bool inReader);
+
+  // Returns true once per tilt-forward gesture (next page direction).
+  // Consumed on read — subsequent calls return false until next gesture.
+  bool wasTiltedForward();
+
+  // Returns true once per tilt-back gesture (previous page direction).
+  // Consumed on read.
+  bool wasTiltedBack();
+
+  // Non-consuming: true if any tilt activity occurred since last call.
+  // Used to reset the auto-sleep inactivity timer.
+  bool hadActivity();
+
+  // Discard any pending tilt events (call when leaving reader or disabling tilt).
+  void clearPendingEvents();
+};