BatteryService.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __BLE_BATTERY_SERVICE_H__
00018 #define __BLE_BATTERY_SERVICE_H__
00019 
00020 #include "ble/BLE.h"
00021 
00022 static const UUID UUID_BATTERY_VOLTAGE = UUID("416B6DFF-D80C-477E-9841-30CB59C65C93");
00023 
00024 
00025 /**
00026 * @class BatteryService
00027 * @brief BLE Battery Service. This service displays the battery level from 0% to 100%, represented as an 8bit number.
00028 * Service:  https://developer.bluetooth.org/gatt/services/Pages/ServiceViewer.aspx?u=org.bluetooth.service.battery_service.xml
00029 * Battery Level Char:  https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.battery_level.xml
00030 */
00031 class BatteryService {
00032 public:
00033 
00034     /**
00035      * @param[in] _ble
00036      *               BLE object for the underlying controller.
00037      * @param[in] level
00038      *               8bit batterly level. Usually used to represent percentage of batterly charge remaining.
00039      */
00040     BatteryService (BLE &_ble, uint8_t level = 100, uint16_t voltage = 0) :
00041         ble(_ble),
00042         batteryLevel(level),
00043         batteryLevelCharacteristic(GattCharacteristic::UUID_BATTERY_LEVEL_CHAR, &batteryLevel, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
00044         batteryVoltage(voltage),
00045         batteryVoltageCharacteristic(UUID_BATTERY_VOLTAGE, &batteryVoltage, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY)
00046          {
00047 
00048         // required for OS X bonding
00049         SecurityManager::SecurityMode_t securityMode = SecurityManager::SECURITY_MODE_ENCRYPTION_NO_MITM;
00050         batteryLevelCharacteristic.requireSecurity(securityMode);
00051 
00052         GattCharacteristic *charTable[] = {&batteryLevelCharacteristic, &batteryVoltageCharacteristic};
00053         GattService         batteryService(GattService::UUID_BATTERY_SERVICE, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
00054 
00055         ble.addService(batteryService);
00056     }
00057 
00058     /**
00059      * @brief Update the battery level with a new value. Valid values lie between 0 and 100,
00060      * anything outside this range will be ignored.
00061      *
00062      * @param newLevel
00063      *              Update to battery level.
00064      */
00065     void updateBatteryLevel(const uint8_t newLevel, const uint16_t newVoltage) {
00066         if (batteryLevel != newLevel) {
00067             batteryLevel = newLevel;
00068             ble.gattServer().write(batteryLevelCharacteristic.getValueHandle(), &batteryLevel, 1);
00069         }
00070         if (batteryVoltage != newVoltage) {
00071             batteryVoltage = newVoltage;
00072             ble.gattServer().write(batteryVoltageCharacteristic.getValueHandle(), reinterpret_cast<uint8_t*>(&batteryVoltage), 2);
00073         }
00074     }
00075 
00076 protected:
00077     /**
00078      * A reference to the underlying BLE instance that this object is attached to.
00079      * The services and characteristics will be registered in this BLE instance.
00080      */
00081     BLE &ble;
00082 
00083     /**
00084      * The current battery level represented as an integer from 0% to 100%.
00085      */
00086     uint8_t    batteryLevel;
00087     /**
00088      * A ReadOnlyGattCharacteristic that allows access to the peer device to the
00089      * batteryLevel value through BLE.
00090      */
00091     ReadOnlyGattCharacteristic<uint8_t> batteryLevelCharacteristic;
00092     
00093     uint16_t batteryVoltage; // voltage in mV
00094     ReadOnlyGattCharacteristic<uint16_t> batteryVoltageCharacteristic;
00095 };
00096 
00097 #endif /* #ifndef __BLE_BATTERY_SERVICE_H__*/