diff --git a/source/buttons.cpp b/source/buttons.cpp
index 1153c4f..0b40a68 100644
--- a/source/buttons.cpp
+++ b/source/buttons.cpp
@@ -5,7 +5,10 @@
 
 extern BLEHidAdafruit blehid;
 
-static uint8_t physBtnMask = 0;   // bitmask of currently-pressed physical buttons
+static uint8_t physBtnMask = 0;
+static uint8_t rawMaskPrev = 0;
+static unsigned long debounceMs = 0;
+static const unsigned long DEBOUNCE_MS = 20;
 
 // Setup 
 void setupPhysicalButtons() {
@@ -36,16 +39,25 @@ void setupPhysicalButtons() {
 void processPhysicalButtons() {
   if (!Bluefruit.connected()) return;
 
-  uint8_t newMask = 0;
-  if (BTN_LEFT_PIN   != BTN_PIN_NONE && digitalRead(BTN_LEFT_PIN)   == LOW) newMask |= MOUSE_BUTTON_LEFT;
-  if (BTN_RIGHT_PIN  != BTN_PIN_NONE && digitalRead(BTN_RIGHT_PIN)  == LOW) newMask |= MOUSE_BUTTON_RIGHT;
-  if (BTN_MIDDLE_PIN != BTN_PIN_NONE && digitalRead(BTN_MIDDLE_PIN) == LOW) newMask |= MOUSE_BUTTON_MIDDLE;
+  uint8_t rawMask = 0;
+  if (BTN_LEFT_PIN   != BTN_PIN_NONE && digitalRead(BTN_LEFT_PIN)   == LOW) rawMask |= MOUSE_BUTTON_LEFT;
+  if (BTN_RIGHT_PIN  != BTN_PIN_NONE && digitalRead(BTN_RIGHT_PIN)  == LOW) rawMask |= MOUSE_BUTTON_RIGHT;
+  if (BTN_MIDDLE_PIN != BTN_PIN_NONE && digitalRead(BTN_MIDDLE_PIN) == LOW) rawMask |= MOUSE_BUTTON_MIDDLE;
 
-  if (newMask != physBtnMask) {
+  if (rawMask != rawMaskPrev) { rawMaskPrev = rawMask; debounceMs = millis(); }
+  if (rawMask != physBtnMask && (millis() - debounceMs >= DEBOUNCE_MS)) {
+    uint8_t newMask = rawMask;
+    uint8_t pressed  = newMask & ~physBtnMask;   // bits that just went down
+    uint8_t released = physBtnMask & ~newMask;    // bits that just went up
     physBtnMask = newMask;
     if (physBtnMask) blehid.mouseButtonPress(physBtnMask);
     else             blehid.mouseButtonRelease();
-    Serial.print("[BTN] mask=0x"); Serial.println(physBtnMask, HEX);
+    if (pressed & MOUSE_BUTTON_LEFT)    Serial.println("[BTN] L press");
+    if (pressed & MOUSE_BUTTON_RIGHT)   Serial.println("[BTN] R press");
+    if (pressed & MOUSE_BUTTON_MIDDLE)  Serial.println("[BTN] M press");
+    if (released & MOUSE_BUTTON_LEFT)   Serial.println("[BTN] L release");
+    if (released & MOUSE_BUTTON_RIGHT)  Serial.println("[BTN] R release");
+    if (released & MOUSE_BUTTON_MIDDLE) Serial.println("[BTN] M release");
   }
 }
 
diff --git a/source/config.h b/source/config.h
index 7058c34..f7b0c65 100644
--- a/source/config.h
+++ b/source/config.h
@@ -60,7 +60,7 @@
 // Physical button pin assignments (hardcoded - set to 0xFF to disable a button)
 // Valid pin numbers: 0-10 (Arduino D0-D10 on XIAO nRF52840 Sense)
 #define BTN_PIN_NONE   0xFF
-#define BTN_LEFT_PIN   BTN_PIN_NONE   // e.g. 0 for D0
+#define BTN_LEFT_PIN   1              // D1, active-low to GND
 #define BTN_RIGHT_PIN  BTN_PIN_NONE   // e.g. 1 for D1
 #define BTN_MIDDLE_PIN BTN_PIN_NONE   // e.g. 2 for D2