Use the microbit as a foot paddle Send Shift-Ctrl-Alt F11 and F12 for the buttons, you can use those a global hotkeys for actions, e.g. mute/unmute microphone

Dependencies:   mbed BLE_API nRF51822

Revision:
0:cb1939018833
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BLE_HID/JoystickService.h	Mon Nov 02 18:25:58 2015 +0000
@@ -0,0 +1,129 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mbed.h"
+
+#include "HIDServiceBase.h"
+
+enum ButtonState
+{
+    BUTTON_UP,
+    BUTTON_DOWN
+};
+
+enum JoystickButton
+{
+    JOYSTICK_BUTTON_1       = 0x1,
+    JOYSTICK_BUTTON_2       = 0x2,
+};
+
+report_map_t JOYSTICK_REPORT_MAP = {
+    USAGE_PAGE(1),      0x01,         // Generic Desktop
+    USAGE(1),           0x04,         // Joystick
+    COLLECTION(1),      0x01,         // Application
+    COLLECTION(1),      0x00,         //  Physical
+    USAGE_PAGE(1),      0x09,         //   Buttons
+    USAGE_MINIMUM(1),   0x01,
+    USAGE_MAXIMUM(1),   0x03,
+    LOGICAL_MINIMUM(1), 0x00,
+    LOGICAL_MAXIMUM(1), 0x01,
+    REPORT_COUNT(1),    0x03,         //   2 bits (Buttons)
+    REPORT_SIZE(1),     0x01,
+    INPUT(1),           0x02,         //   Data, Variable, Absolute
+    REPORT_COUNT(1),    0x01,         //   6 bits (Padding)
+    REPORT_SIZE(1),     0x05,
+    INPUT(1),           0x01,         //   Constant
+    USAGE_PAGE(1),      0x01,         //   Generic Desktop
+    USAGE(1),           0x30,         //   X
+    USAGE(1),           0x31,         //   Y
+    USAGE(1),           0x32,         //   Z
+    USAGE(1),           0x33,         //   Rx
+    LOGICAL_MINIMUM(1), 0x81,         //   -127
+    LOGICAL_MAXIMUM(1), 0x7f,         //   127
+    REPORT_SIZE(1),     0x08,         //   Three bytes
+    REPORT_COUNT(1),    0x04,
+    INPUT(1),           0x02,         //   Data, Variable, Absolute (unlike mouse)
+    END_COLLECTION(0),
+    END_COLLECTION(0),
+};
+
+uint8_t report[] = { 0, 0, 0, 0, 0 };
+
+class JoystickService: public HIDServiceBase
+{
+public:
+    JoystickService(BLE &_ble) :
+        HIDServiceBase(_ble,
+                       JOYSTICK_REPORT_MAP, sizeof(JOYSTICK_REPORT_MAP),
+                       inputReport          = report,
+                       outputReport         = NULL,
+                       featureReport        = NULL,
+                       inputReportLength    = sizeof(inputReport),
+                       outputReportLength   = 0,
+                       featureReportLength  = 0,
+                       reportTickerDelay    = 20),
+        buttonsState (0),
+        failedReports (0)
+    {
+        speed[0] = 0;
+        speed[1] = 0;
+        speed[2] = 0;
+        speed[3] = 0;
+
+        startReportTicker();
+    }
+
+    int setSpeed(int8_t x, int8_t y, int8_t z)
+    {
+        speed[0] = x;
+        speed[1] = y;
+        speed[2] = z;
+
+        return 0;
+    }
+
+    int setButton(JoystickButton button, ButtonState state)
+    {
+        if (state == BUTTON_UP)
+            buttonsState &= ~(button);
+        else
+            buttonsState |= button;
+
+        return 0;
+    }
+
+    virtual void sendCallback(void) {
+        if (!connected)
+            return;
+
+        report[0] = buttonsState & 0x7;
+        report[1] = speed[0];
+        report[2] = speed[1];
+        report[3] = speed[2];
+        report[4] = speed[3];
+
+        if (send(report))
+            failedReports++;
+    }
+
+protected:
+    uint8_t buttonsState;
+    uint8_t speed[4];
+
+public:
+    uint32_t failedReports;
+};
+