added hardware

arduino/README.md

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+# Nexus Game Controller
+
+A game controller using a Seeed Studio XIAO nRF52840 Sense board that emulates a Bluetooth keyboard.
+
+## Hardware
+- [Seeed Studio XIAO nRF52840 Sense](#https://www.seeedstudio.com/Seeed-XIAO-BLE-Sense-nRF52840-p-5253.html)
+- 9 [push buttons](https://rpishop.cz/komponenty/6128-pimoroni-cerne-arkadove-tlacitko.html) connected to pins D1-D6 and D8-D10.
+
+## Features
+- **Bluetooth LE Keyboard:** Connects to any computer or mobile device as a standard keyboard.
+- **Multi-Event Buttons:** Each of the 9 buttons supports three types of interactions:
+    - Single Click
+    - Double Click
+    - Long Press
+- **Character Mapping:** Each button event sends a unique character.
+- **Serial Debugging:** Outputs button events and Bluetooth connection status to the serial monitor.
+
+## Button Mappings
+
+| Button | Single Click | Double Click | Long Press |
+|--------|--------------|--------------|------------|
+| D1     | `a`          | `b`          | `c`        |
+| D2     | `d`          | `e`          | `f`        |
+| D3     | `g`          | `h`          | `i`        |
+| D4     | `j`          | `k`          | `l`        |
+| D5     | `m`          | `n`          | `o`        |
+| D6     | `p`          | `q`          | `r`        |
+| D8     | `s`          | `t`          | `u`        |
+| D9     | `v`          | `w`          | `x`        |
+| D10    | `y`          | `z`          | `1`        |
+
+## How to Use
+
+1.  **Setup Arduino IDE:**
+    - Install the "Seeed nRF52 Boards" package.
+    - Select "Seeed XIAO BLE Sense - nRF52840" as the board.
+    - Install the "Adafruit Bluefruit nRF52" library.
+2.  **Upload:** Compile and upload the [sketch](/arduino/sketch.ino) to your XIAO board.
+3.  **Connect:** Scan for Bluetooth devices on your computer or mobile device and connect to "Nexus Game Controller".
+4.  **Play:** Press the buttons to send keystrokes. Open the Serial Monitor at 115200 baud to see debug information.
+
+## 3D Print
+
+![Hexagon](/arduino/Krabicka_hexagon.png)
+
+You can import the [3mf file](/arduino/Krabicka_hexagon.3mf) to your slicer for printing.
+
+## Customize your design
+
+Open the [3D model](/arduino/Krabicka_hexagon.FCStd) in FreeCAD to model your changes.

arduino/sketch.ino

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+#include <bluefruit.h>
+#include <bluefruit.h>
+
+// Pin definitions for the 9 buttons
+const int buttonPins[] = {1, 2, 3, 4, 5, 6, 8, 9, 10};
+const int numButtons = sizeof(buttonPins) / sizeof(buttonPins[0]);
+
+// Button state tracking
+struct Button {
+  int pin;
+  bool lastState;
+  unsigned long lastDebounceTime;
+  unsigned long pressTime;
+  int clickCount;
+  bool isPressed;
+  bool longPressHandled;
+};
+
+Button buttons[numButtons];
+
+// Debounce and timing constants
+const unsigned long debounceDelay = 50;
+const unsigned long doubleClickDelay = 400;
+const unsigned long longPressDelay = 1000;
+
+// BLE Keyboard object
+BLEDis bledis;
+BLEHidAdafruit blehid;
+
+// Character mapping for each event
+// 9 buttons * 3 events/button = 27 characters
+const char eventChars[numButtons][3] = {
+  {'a', 'b', 'c'}, // Button D1: single, double, long
+  {'d', 'e', 'f'}, // Button D2: single, double, long
+  {'g', 'h', 'i'}, // Button D3: single, double, long
+  {'j', 'k', 'l'}, // Button D4: single, double, long
+  {'m', 'n', 'o'}, // Button D5: single, double, long
+  {'p', 'q', 'r'}, // Button D6: single, double, long
+  {'s', 't', 'u'}, // Button D8: single, double, long
+  {'v', 'w', 'x'}, // Button D9: single, double, long
+  {'y', 'z', '1'}  // Button D10: single, double, long
+};
+
+void setup() {
+  Serial.begin(115200);
+  //while ( !Serial ) delay(10); // Wait for serial port to connect.
+
+  Serial.println("Nexus Game Controller Starting...");
+
+  // Initialize buttons
+  for (int i = 0; i < numButtons; i++) {
+    buttons[i].pin = buttonPins[i];
+    pinMode(buttons[i].pin, INPUT_PULLUP);
+    buttons[i].lastState = HIGH;
+    buttons[i].lastDebounceTime = 0;
+    buttons[i].pressTime = 0;
+    buttons[i].clickCount = 0;
+    buttons[i].isPressed = false;
+    buttons[i].longPressHandled = false;
+  }
+
+  // Setup Bluetooth
+  Bluefruit.begin();
+  Bluefruit.setName("Nexus Game Controller");
+  Bluefruit.setTxPower(4);
+
+  // Configure and start BLE services
+  bledis.setManufacturer("Seeed Studio");
+  bledis.setModel("XIAO nRF52840 Sense");
+  bledis.begin();
+
+  blehid.begin();
+
+  // Start advertising
+  Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
+  Bluefruit.Advertising.addTxPower();
+  Bluefruit.Advertising.addAppearance(BLE_APPEARANCE_HID_KEYBOARD);
+  Bluefruit.Advertising.addService(blehid);
+  Bluefruit.Advertising.addName();
+  
+  Bluefruit.Advertising.restartOnDisconnect(true);
+  Bluefruit.Advertising.setInterval(32, 244); // in unit of 0.625 ms
+  Bluefruit.Advertising.setFastTimeout(30); // number of seconds in fast advertising mode
+  Bluefruit.Advertising.start(0); // 0 = Don't stop advertising after n seconds
+
+  Serial.println("Advertising...");
+
+  // Set up connection/disconnection callbacks
+  Bluefruit.Periph.setConnectCallback(connect_callback);
+  Bluefruit.Periph.setDisconnectCallback(disconnect_callback);
+}
+
+void connect_callback(uint16_t conn_handle) {
+  (void) conn_handle;
+  Serial.println("Bluetooth connected");
+}
+
+void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
+  (void) conn_handle;
+  (void) reason;
+  Serial.println("Bluetooth disconnected");
+}
+
+
+void loop() {
+  for (int i = 0; i < numButtons; i++) {
+    handleButton(&buttons[i], i);
+  }
+}
+
+void handleButton(Button* b, int buttonIndex) {
+  bool reading = digitalRead(b->pin);
+
+  // Debounce logic
+  if (reading != b->lastState) {
+    b->lastDebounceTime = millis();
+  }
+
+  if ((millis() - b->lastDebounceTime) > debounceDelay) {
+    // If the button state has been stable
+    if (reading == LOW && !b->isPressed) { // Button just pressed
+      b->isPressed = true;
+      b->pressTime = millis();
+      b->clickCount++;
+      b->longPressHandled = false;
+    } else if (reading == HIGH && b->isPressed) { // Button just released
+      b->isPressed = false;
+      if (!b->longPressHandled) {
+        // It's a click, but we need to wait for a potential double click
+      } else {
+        // This was a long press, so we do nothing on release
+        b->longPressHandled = false; // Reset for next time
+      }
+    }
+  }
+
+  // Check for long press
+  if (b->isPressed && !b->longPressHandled && (millis() - b->pressTime > longPressDelay)) {
+    triggerEvent(buttonIndex, 2); // Long Press
+    b->longPressHandled = true;
+    b->clickCount = 0; // Reset click count after a long press
+  }
+
+  // Check for single/double click timeout
+  if (b->clickCount > 0 && !b->isPressed && (millis() - b->pressTime > doubleClickDelay)) {
+    if (!b->longPressHandled) {
+      if (b->clickCount == 1) {
+        triggerEvent(buttonIndex, 0); // Single Click
+      } else if (b->clickCount == 2) {
+        triggerEvent(buttonIndex, 1); // Double Click
+      }
+    }
+    b->clickCount = 0;
+  }
+
+  b->lastState = reading;
+}
+
+void triggerEvent(int buttonIndex, int eventType) {
+  // eventType: 0 = single, 1 = double, 2 = long
+  char key = eventChars[buttonIndex][eventType];
+  
+  const char* eventStr[] = {"single click", "double click", "long press"};
+
+  Serial.print("Button D");
+  Serial.print(buttonPins[buttonIndex]);
+  Serial.print(" triggered ");
+  Serial.print(eventStr[eventType]);
+  Serial.print(" event. Character '");
+  Serial.print(key);
+  Serial.println("' has been sent.");
+
+  if (Bluefruit.connected()) {
+    blehid.keyPress(key);
+    delay(10); // a small delay to prevent flooding
+    blehid.keyRelease();
+  }
+}