added proper kinematics

src/main.cpp

@@ -50,6 +50,20 @@
 #define DEFAULT_SPEED   600.0f    // steps/sec
 #define DEFAULT_ACCEL   100.0f    // steps/sec²
 
+// ─── Homing configuration ─────────────────────────────────────────
+// TUNE these after first hardware test.
+//   SEEK_DIR: +1 = CW (positive steps), -1 = CCW toward stop
+//   SEEK_STEPS: must exceed maximum arm travel (~240° = 1365 steps)
+//   OP_OFFSET: steps from the mechanical stop to the operating home
+//              (derived from original PositionControl.cpp homing offsets)
+#define M1_HOME_DIR      (-1)     // ← TUNE: flip to +1 if M1 moves wrong way
+#define M2_HOME_DIR      (+1)     // ← TUNE: flip to -1 if M2 moves wrong way
+#define HOME_SEEK_STEPS  1600     // ← TUNE: > max travel; 1600 ≈ 281° of a rev
+#define HOME_SPEED       180.0f   // ← TUNE: slow seek to avoid missing steps
+#define HOME_ACCEL        50.0f   // ← TUNE: gentle accel during seek
+#define M1_OP_OFFSET      550     // ← TUNE: steps from M1 stop → operating home
+#define M2_OP_OFFSET     -530     // ← TUNE: steps from M2 stop → operating home
+
 // ─── BLE UUIDs ────────────────────────────────────────────────────
 #define SERVICE_UUID    "a0b1c2d3-e4f5-6789-abcd-ef0123456700"
 #define CMD_UUID        "a0b1c2d3-e4f5-6789-abcd-ef0123456701"
@@ -73,6 +87,7 @@ const unsigned long NOTIFY_INTERVAL_MS = 200;
 // ─── Forward declarations ─────────────────────────────────────────
 void parseCommand(const String& cmd);
 void sendPosition();
+void runHoming();
 
 // ─── BLE Server Callbacks ─────────────────────────────────────────
 class ServerCallbacks : public BLEServerCallbacks {
@@ -130,7 +145,13 @@ void parseCommand(const String& cmd) {
         Serial.printf("[CFG] Acceleration → %.0f steps/sec²\n", acc);
         return;
     }
-    // HOME1
+    // HOME – full stall-seek homing sequence
+    if (cmd == "HOME") {
+        Serial.println("[HOME] Received HOME command");
+        runHoming();
+        return;
+    }
+    // HOME1 / HOME2 – manual zero (soft zero, no motion)
     if (cmd == "HOME1") {
         stepper1.setCurrentPosition(0);
         Serial.println("[S1] Zeroed");
@@ -152,6 +173,80 @@ void parseCommand(const String& cmd) {
     Serial.printf("[CMD] Unknown command: '%s'\n", cmd.c_str());
 }
 
+// ─── Stall-based homing sequence ─────────────────────────────────
+/**
+ * Drives each motor slowly into its mechanical hard stop (the arm
+ * folds against the motor housing).  The 28BYJ-48 stalls harmlessly
+ * for a fraction of a second at the stop.  After both stops are
+ * found, the arm backs off to the operating home position and both
+ * step counters are zeroed.
+ *
+ * This is a BLOCKING call — BLE is not serviced during homing
+ * (~15-20 s total). The browser shows "Homing…" until the
+ * HOMED notify arrives.
+ *
+ * Tune M1_HOME_DIR, M2_HOME_DIR, HOME_SEEK_STEPS, and OP_OFFSETs
+ * after the first hardware test.
+ */
+void runHoming() {
+    Serial.println("[HOME] Starting homing sequence…");
+
+    // Reduce speed for the seek phase
+    stepper1.setMaxSpeed(HOME_SPEED);
+    stepper1.setAcceleration(HOME_ACCEL);
+    stepper2.setMaxSpeed(HOME_SPEED);
+    stepper2.setAcceleration(HOME_ACCEL);
+
+    // ── Seek M1 to its mechanical stop ───────────────────────────
+    Serial.println("[HOME] Seeking M1 stop…");
+    stepper1.move(M1_HOME_DIR * HOME_SEEK_STEPS);
+    while (stepper1.isRunning()) {
+        stepper1.run();
+        stepper2.run(); // keep M2 coils energised during M1 seek
+    }
+    stepper1.setCurrentPosition(0);
+    Serial.println("[HOME] M1 stop found → zeroed");
+    delay(200); // brief pause before M2 seek
+
+    // ── Seek M2 to its mechanical stop ───────────────────────────
+    Serial.println("[HOME] Seeking M2 stop…");
+    stepper2.move(M2_HOME_DIR * HOME_SEEK_STEPS);
+    while (stepper2.isRunning()) {
+        stepper1.run();
+        stepper2.run();
+    }
+    stepper2.setCurrentPosition(0);
+    Serial.println("[HOME] M2 stop found → zeroed");
+    delay(200);
+
+    // ── Move to operating home (restore normal speed) ─────────────
+    stepper1.setMaxSpeed(DEFAULT_SPEED);
+    stepper1.setAcceleration(DEFAULT_ACCEL);
+    stepper2.setMaxSpeed(DEFAULT_SPEED);
+    stepper2.setAcceleration(DEFAULT_ACCEL);
+
+    Serial.println("[HOME] Moving to operating home…");
+    stepper1.moveTo(M1_OP_OFFSET);
+    stepper2.moveTo(M2_OP_OFFSET);
+    while (stepper1.isRunning() || stepper2.isRunning()) {
+        stepper1.run();
+        stepper2.run();
+    }
+
+    // Declare operating home as the new step zero
+    stepper1.setCurrentPosition(0);
+    stepper2.setCurrentPosition(0);
+    Serial.println("[HOME] Homing complete — at operating home (0, 0)");
+
+    // Notify the browser so it can sync its step counters
+    if (bleConnected && pStatusChar) {
+        pStatusChar->setValue("HOMED");
+        pStatusChar->notify();
+    }
+    delay(50);
+    sendPosition(); // immediately follow with P:0,0
+}
+
 // ─── Send current positions via BLE NOTIFY ────────────────────────
 void sendPosition() {
     if (!bleConnected || !pStatusChar) return;