Add EEPROM-backed seat position setting

Auto_Seat.ino

@@ -1,5 +1,6 @@
 // Auto_Seat
-// Timed automatic seat controller with relay protection.
+// EEPROM-backed automatic seat controller.
+#include <EEPROM.h>
 
 #define seatRelayD8 8
 #define seatRelayD9 9
@@ -11,31 +12,24 @@ const int PARKING_ON_THRESHOLD = 950;
 const int PARKING_OFF_THRESHOLD = 940;
 const int DOWN_SPEED_NUM = 11;
 const int DOWN_SPEED_DEN = 10;
-const unsigned long IGNITION_STABILIZE_MS = 1000UL;
 const unsigned long DRIVE_CONFIRM_MS = 80UL;
 const unsigned long PARK_CONFIRM_MS = 250UL;
-const unsigned long RELAY_DEADTIME_MS = 120UL;
+const int EEPROM_MAGIC_ADDR = 0;
-const unsigned long DOWN_EDGE_MARGIN_MS = 300UL;
+const byte EEPROM_MAGIC_VALUE = 0x64;
+const int EEPROM_SEAT_POSITION_ADDR = 2;
 
 boolean ignitionState = LOW;
 boolean parkingState = LOW;
-boolean prevIgnitionState = LOW;
 boolean confirmedDriveMode = LOW;
 boolean pendingDriveMode = LOW;
-bool isStabilizing = false;
-bool downEdgeMarginActive = false;
 int parkingRawValue = 0;
+uint16_t storedSeatPositionMs = 0;
 long currentPosMs = 0;
 long targetPosMs = 0;
 long downSpeedRemainder = 0;
 unsigned long lastTime = 0;
-unsigned long stabilizeStartTime = 0;
 unsigned long pendingDriveModeStartTime = 0;
-unsigned long relayDeadtimeStartTime = 0;
+int seatAction = 0;
-unsigned long downEdgeMarginTime = DOWN_EDGE_MARGIN_MS;
-int currentSeatAction = 0;
-int requestedSeatAction = 0;
-int lastStoppedSeatAction = 0;
 
 void setup() {
   pinMode(parkingPin, INPUT);
@@ -43,7 +37,7 @@ void setup() {
   pinMode(seatRelayD8, OUTPUT);
   pinMode(seatRelayD9, OUTPUT);
   applySeatAction(0);
-  seat(0);
+  loadSettings();
   measurement();
   confirmedDriveMode = getRawDriveMode();
   pendingDriveMode = confirmedDriveMode;
@@ -53,27 +47,13 @@ void setup() {
 
 void loop() {
   measurement();
-  unsigned long currentTime = millis();
+  unsigned long now = millis();
-  unsigned long deltaTime = currentTime - lastTime;
+  unsigned long deltaTime = now - lastTime;
-  lastTime = currentTime;
+  lastTime = now;
-
+  updateConfirmedDriveMode(now);
-  if (prevIgnitionState == LOW && ignitionState == HIGH) {
-    isStabilizing = true;
-    stabilizeStartTime = currentTime;
-  }
-  prevIgnitionState = ignitionState;
-
-  if (isStabilizing && currentTime - stabilizeStartTime < IGNITION_STABILIZE_MS) {
-    seat(0);
-    updateRelayOutput(currentTime);
-    return;
-  }
-  isStabilizing = false;
-
-  updateConfirmedDriveMode(currentTime);
   targetPosMs = getTargetForConfirmedMode();
   updateMovement(deltaTime);
-  updateRelayOutput(currentTime);
+  applySeatAction(seatAction);
 }
 
 void measurement() {
@@ -84,80 +64,51 @@ void measurement() {
 }
 
 boolean getRawDriveMode() { return ignitionState == HIGH && parkingState == LOW; }
-long getTargetForConfirmedMode() { return confirmedDriveMode == HIGH ? SEAT_HARD_LIMIT_UP_MS : 0; }
+long getTargetForConfirmedMode() { return confirmedDriveMode == HIGH ? storedSeatPositionMs : 0; }
 
-void updateConfirmedDriveMode(unsigned long currentTime) {
+void updateConfirmedDriveMode(unsigned long now) {
   boolean rawDriveMode = getRawDriveMode();
   if (rawDriveMode != pendingDriveMode) {
     pendingDriveMode = rawDriveMode;
-    pendingDriveModeStartTime = currentTime;
+    pendingDriveModeStartTime = now;
   }
   unsigned long confirmMs = pendingDriveMode == HIGH ? DRIVE_CONFIRM_MS : PARK_CONFIRM_MS;
-  if (pendingDriveMode != confirmedDriveMode && currentTime - pendingDriveModeStartTime >= confirmMs) {
+  if (pendingDriveMode != confirmedDriveMode && now - pendingDriveModeStartTime >= confirmMs) {
     confirmedDriveMode = pendingDriveMode;
   }
 }
 
 void updateMovement(unsigned long deltaTime) {
-  if (downEdgeMarginActive) {
-    seat(-1);
-    downEdgeMarginTime += deltaTime;
-    if (downEdgeMarginTime >= DOWN_EDGE_MARGIN_MS) {
-      downEdgeMarginActive = false;
-      downEdgeMarginTime = DOWN_EDGE_MARGIN_MS;
-      seat(0);
-    }
-    return;
-  }
-
   if (currentPosMs < targetPosMs) {
-    seat(1);
+    seatAction = 1;
     currentPosMs += deltaTime;
-    if (currentPosMs >= targetPosMs) {
+    if (currentPosMs >= targetPosMs) { currentPosMs = targetPosMs; seatAction = 0; }
-      currentPosMs = targetPosMs;
-      seat(0);
-    }
   } else if (currentPosMs > targetPosMs) {
-    seat(-1);
+    seatAction = -1;
     long scaled = deltaTime * DOWN_SPEED_NUM + downSpeedRemainder;
     currentPosMs -= scaled / DOWN_SPEED_DEN;
     downSpeedRemainder = scaled % DOWN_SPEED_DEN;
-    if (currentPosMs <= targetPosMs) {
+    if (currentPosMs <= targetPosMs) { currentPosMs = targetPosMs; downSpeedRemainder = 0; seatAction = 0; }
-      currentPosMs = targetPosMs;
-      downSpeedRemainder = 0;
-      if (targetPosMs == 0) {
-        downEdgeMarginActive = true;
-        downEdgeMarginTime = 0;
-      } else {
-        seat(0);
-      }
-    }
   } else {
-    seat(0);
+    seatAction = 0;
   }
 }
 
+void loadSettings() {
+  if (EEPROM.read(EEPROM_MAGIC_ADDR) != EEPROM_MAGIC_VALUE) {
+    EEPROM.update(EEPROM_MAGIC_ADDR, EEPROM_MAGIC_VALUE);
+    writeUint16(EEPROM_SEAT_POSITION_ADDR, SEAT_HARD_LIMIT_UP_MS);
+  }
+  storedSeatPositionMs = readUint16(EEPROM_SEAT_POSITION_ADDR);
+  if (storedSeatPositionMs > SEAT_HARD_LIMIT_UP_MS) {
+    storedSeatPositionMs = SEAT_HARD_LIMIT_UP_MS;
+    writeUint16(EEPROM_SEAT_POSITION_ADDR, storedSeatPositionMs);
+  }
+}
+
+uint16_t readUint16(int addr) { return (uint16_t)EEPROM.read(addr) | ((uint16_t)EEPROM.read(addr + 1) << 8); }
+void writeUint16(int addr, uint16_t value) { EEPROM.update(addr, value & 0xFF); EEPROM.update(addr + 1, (value >> 8) & 0xFF); }
 void setRelay(int relayPin, boolean state) { digitalWrite(relayPin, state ? LOW : HIGH); }
-void seat(int action) { requestedSeatAction = action; }
-
-void updateRelayOutput(unsigned long currentTime) {
-  if (requestedSeatAction == currentSeatAction) {
-    applySeatAction(currentSeatAction);
-    return;
-  }
-  if (currentSeatAction != 0) {
-    lastStoppedSeatAction = currentSeatAction;
-    currentSeatAction = 0;
-    relayDeadtimeStartTime = currentTime;
-    applySeatAction(0);
-    return;
-  }
-  bool sameDirectionResume = requestedSeatAction != 0 && requestedSeatAction == lastStoppedSeatAction;
-  bool deadtimeDone = currentTime - relayDeadtimeStartTime >= RELAY_DEADTIME_MS;
-  if (sameDirectionResume || deadtimeDone) currentSeatAction = requestedSeatAction;
-  applySeatAction(currentSeatAction);
-}
-
 void applySeatAction(int action) {
   if (action == 1) { setRelay(seatRelayD8, 1); setRelay(seatRelayD9, 0); }
   else if (action == -1) { setRelay(seatRelayD8, 0); setRelay(seatRelayD9, 1); }