[蓝牙]CoreBluetooth

硬體週邊Tips

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• 1 藍牙
  • 1.1 BLE(CoreBluetooth)
    • 1.1.1 Discover/Connect
      • 1.1.1.1 CBCentralManager
      • 1.1.1.2 centralManagerDidUpdateState
      • 1.1.1.3 scanForPeripheralsWithServices
      • 1.1.1.4 didDiscoverPeripheral
      • 1.1.1.5 stopScan
      • 1.1.1.6 connectPeripheral
      • 1.1.1.7 didConnectPeripheral
    • 1.1.2 Explore
      • 1.1.2.1 CBPeripheral
      • 1.1.2.2 didConnectPeripheral
      • 1.1.2.3 didDiscoverServices
      • 1.1.2.4 didDiscoverCharacteristicsForService
    • 1.1.3 Interact
      • 1.1.3.1 didDiscoverCharacteristicsForService
      • 1.1.3.2 didUpdateValueForCharacteristic
    • 1.1.4 ReConnect
• 2 相機
• 3 GPS
• 4 電池
• 5 晃動
• 6 距離

藍牙

BLE(CoreBluetooth)

Bluetooth 4.0之後就將通訊模式分為高速及低速種類，目前將低速低耗能簡稱為BLE，可以連接一些量測型的感測器類型像：心跳計、血壓…等，這使得iDevice不再是利用MFi認證過的Dock才能與iDevice連接，增加APP型態的多元。

如果想要跟BLE週邊連接，iOS提供了CoreBluetooth framework來與週邊連接，整個程式中分為Discover、Connect、Explore、Interact，下面將會以從連線至BLE讀取到資料為原則來介紹。

Discover/Connect

依照箭頭方向由上而下為順序來依序完成Discover與Connect流程，下面會針對此流程加上範例來介紹

CBCentralManager

要使用CoreBluetooth就要先了解一下CBCentralManager，這個Object掌控整個BLE的管理，一開始要先對CBCentralManager來做個初始化

CBCentralManager *CM = [[CBCentralManager alloc] initWithDelegate:self queue:nil];

centralManagerDidUpdateState

在初始化時指定Delegate為self，並在.h內加上Delegate宣告：

@interface TestCoreBluetooth : NSObject<CBCentralManagerDelegate> {:::}

加完宣告後就需要完成centralManagerDidUpdateState這個Delegate，

-(void)centralManagerDidUpdateState:(CBCentralManager*)cManager{    NSMutableString* nsmstring=[NSMutableString stringWithString:@"UpdateState:"];    BOOL isWork=FALSE;    switch (cManager.state) {        case CBCentralManagerStateUnknown:            [nsmstring appendString:@"Unknown\n"];            break;        case CBCentralManagerStateUnsupported:            [nsmstring appendString:@"Unsupported\n"];                        break;        case CBCentralManagerStateUnauthorized:            [nsmstring appendString:@"Unauthorized\n"];            break;        case CBCentralManagerStateResetting:            [nsmstring appendString:@"Resetting\n"];            break;        case CBCentralManagerStatePoweredOff:            [nsmstring appendString:@"PoweredOff\n"];            if (connectedPeripheral!=NULL){                [CM cancelPeripheralConnection:connectedPeripheral];            }            break;        case CBCentralManagerStatePoweredOn:            [nsmstring appendString:@"PoweredOn\n"];            isWork=TRUE;            break;        default:            [nsmstring appendString:@"none\n"];             break;    }    NSLog(@"%@",nsmstring);    [delegate didUpdateState:isWork message:nsmstring getStatus:cManager.state];}

依照centralManagerDidUpdateState來結果來判斷iDevice是否支援BLE，畢竟BLE是在iphone 4s、New iPad之後才有的，可以根據此項來決定APP的功能或其他提示使用者的動作。

scanForPeripheralsWithServices

確定周邊支援BLE且運作正常後，我們就要來開啟BLE搜尋功能來尋找BLE的週邊，當週邊接收到搜尋功能的廣播時就會在一定時間內回覆，在此我們可以設定一個2秒的Timer來停止scan

CBCentralManager *CM = [[CBCentralManager alloc] initWithDelegate:self queue:nil];[CM scanForPeripheralsWithServices:nil options:options];[NSTimer scheduledTimerWithTimeInterval:2.0f target:self selector:@selector(scanTimeout:) userInfo:nil repeats:NO];

設定2秒後觸發執行scanTimeout method，再將scanForPeripheralsWithServices的值設為nil，代表搜尋的Service type不受限制，當你只是要搜尋特定的對向時可以將它的UUID填入，像：

        NSArray*uuidArray= [NSArray arrayWithObjects:[CBUUID UUIDWithString:@"180D"], nil];        [CM scanForPeripheralsWithServices:uuidArray options:options];

其中「UUIDWithString:@"180D"」的180D就是Heart Rate Service type，如果有指定Service type，則結果就會將週邊有Heart Rate一一列出來，想要知道這類的Service Type可以到Bluetooth官網查詢。

一互了解Service type是哪一種類型時就可以來做對應的流程及資料的解析，也可以製作出符合標準週邊的APP。

didDiscoverPeripheral

didDiscoverPeripheral這是屬於Delegate，所以要按照它預設的宣告將要處理的過程寫在裡面，格式如下：

-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{//處理過程}

advertisementData會報告可以連線的週邊內容，像這樣：

adverisement:{    kCBAdvDataLocalName = "INFOS 4090v35.05";    kCBAdvDataServiceUUIDs =     (        "Unknown (<fff0>)"    );    kCBAdvDataTxPowerLevel = 0;}

RSSI是訊號的強度，是以NSNumber Object存在，整個範例可以是這樣子：

-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI{        NSMutableString* nsmstring=[NSMutableString stringWithString:@"\n"];    [nsmstring appendString:@"Peripheral Info:"];    [nsmstring appendFormat:@"NAME: %@\n",peripheral.name];    [nsmstring appendFormat:@"RSSI: %@\n",RSSI];        if (peripheral.isConnected){        [nsmstring appendString:@"isConnected: connected"];    }else{        [nsmstring appendString:@"isConnected: disconnected"];    }    NSLog(@"adverisement:%@",advertisementData);    [nsmstring appendFormat:@"adverisement:%@",advertisementData];    [nsmstring appendString:@"didDiscoverPeripheral\n"];    NSLog(@"%@",nsmstring);}

結果輸出：

2013-02-25 14:43:17.243 gw-health-01[141:907] Peripheral Info:NAME: INFOS 4090v35.05RSSI: -69isConnected: disconnectedadverisement:{    kCBAdvDataServiceUUIDs =     (        "Unknown (<fff0>)"    );}

發現可連線的BLE週邊就會不斷的執行didDiscoverPeripheral 這個Delegate，所以要利用這個狀況將每次發現BLE週邊存入Array，再提供給USER選擇，或是從中可以去判斷某個特別的週邊是否存在而決定要不要連線。

stopScan

執行scanForPeripheralsWithServices 掃描周邊時設定一個2秒的Timer，當時間到時就停止scan，一般來說2秒內無反應就可以當作是沒有其他週邊回應，承上面scanForPeripheralsWithServices， 將stopScan寫在scanTimeout裡面：

- (void) scanTimeout:(NSTimer*)timer{    if (CM!=NULL){        [CM stopScan];    }else{        NSLog(@"CM is Null!");    }    NSLog(@"scanTimeout");}

connectPeripheral

利用didDiscoverPeripheral所得到的BLE週邊列表讓User選擇要連線的BLE，再將 CBPeripheral傳入connectPeripheral進行連線，格式：

       [CBCentralManager connectPeripheral:CBPeripheral* options:NSDictionary*]

在此將它包裝成一個connect Method，

- (void) connect:(CBPeripheral*)peripheral{    if (![peripheral isConnected]) {[CM connectPeripheral:peripheral options:nil];        connectedPeripheral=peripheral;}}

option傳入nil，connectPeripheral傳入Method connect的值。

didConnectPeripheral

執行connectPeripheral之後並連線成功後就會引發didConnectPeripheral的Delegate：

-(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{:::       }

在這裡有個重點，當連線成功後引發Delegate時，就必需要針對其CBPeripheral來馬上進行discoverServices的動作，去了解週邊提供什麼樣的Services

-(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{    NSLog(@"Connect To Peripheral with name: %@\nwith UUID:%@\n",peripheral.name,CFUUIDCreateString(NULL, peripheral.UUID));    peripheral.delegate=self;    [peripheral discoverServices:nil];//一定要執行"discoverService"功能去尋找可用的Service    }

執行discoverServices之後又會引發另一個Delegate叫「didDiscoverServices」，接下來則會在Explore中介紹。

Explore

Discover/Connect 中使用CBCentralManager進行連線/搜尋BLE周邊的功能，連線之後需要靠的是CBPeripherall來傳送/接收資料。

CBPeripheral

使用CBPeripheral使需要設定Delegate才可以進行連線的動作，加上之前加入的CBCentralManagerDelegate，CODE就變成：

@interface DYCoreBluetooth : NSObject<CBCentralManagerDelegate, CBPeripheralDelegate> {:::    }

之後連線的重點全都是在Delegate的互動，查看Service Type或是有什麼樣的Services可以提供。

didConnectPeripheral

前面有稍為介紹didConnectPeripheral，這是在連線成功後就會引發的Delegate，但一定要在這裡執行一些Method才可以順利的引發另一個CBPeripheral的Delegate去查看有什麼樣的Services

-(void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{    NSLog(@"Connect To Peripheral with name: %@\nwith UUID:%@\n",peripheral.name,CFUUIDCreateString(NULL, peripheral.UUID));        peripheral.delegate=self;    [peripheral discoverServices:nil];//一定要執行"discoverService"功能去尋找可用的Service        }

例子中已經將「 peripheral.delegate=self」，所以接下來進行 peripheral的任何動做引發的Delegate都在這個Object中，執行「discoverServices] Method，讓它去尋找Services，一找到Services就又會引發「didDiscoverServices」Delegate，這樣我們就可以了解有什麼Services。

didDiscoverServices

從這裡開始就是最關鍵

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {    NSLog(@"didDiscoverServices:\n");        if( peripheral.UUID == NULL  ) return; // zach ios6 added        if (!error) {        NSLog(@"====%@\n",peripheral.name);        NSLog(@"=========== %d of service for UUID %@ ===========\n",peripheral.services.count,CFUUIDCreateString(NULL,peripheral.UUID));        for (CBService *p in peripheral.services){            NSLog(@"Service found with UUID: %@\n", p.UUID);            [peripheral discoverCharacteristics:nil forService:p];        }            }    else {        NSLog(@"Service discovery was unsuccessfull !\n");    }    }

peripheral.services.count 會知道有多少個Services，在每個Servces中還會有Characteristics需要了解，所以會針對每個Service來執行 peripheral discoverCharacteristics: forService:去了解每個Service下有多少個Characteristics提供傳送/接收的溝通，在執行discoverCharacteristics時也引發了didDiscoverCharacteristicsForService Delegate，最後再由didDiscoverCharacteristicsForService真正的判斷什麼樣的Service什麼樣的Characteristics再進行處理之後收到的資料，例如： 發現2A37的Characteristic，就要進行註冊通知，到時候BLE週邊發訊息過來才會在收到當下得到資料。

didDiscoverCharacteristicsForService

整個最關鍵的地方就是這個Delegate，程式架構如下：

-(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{    :::      }

Interact

最後完成didDiscoverCharacteristicsForService之後，整個連線過程就算是完成，之後的didUpdateValueForCharacteristic是整個資料接收的主要Delegate，經過接收到的資料引發Delegate進行即時處理就可以取得BLE週邊的訊息，再使用writeValue的Method寫入資料到BLE週邊，整個BLE的最基本使用方式就大致上完成。

didDiscoverCharacteristicsForService

由Apple提供的資料擷取某部分來了解架構，等下程式就是利用這架構去一一尋訪所有的CharacteristicsForService

每樣Servic下都會有很多的Characteristics，Characteristics是提供資料傳遞的重點，它會有個UUID編號，再由這 個編號去Bluetooth 官方查表得到是哪種資料格式，再將資料解開加以使用。

真正的例子：

-(void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error{        CBService *s = [peripheral.services objectAtIndex:(peripheral.services.count - 1)];    NSLog(@"=========== Service UUID %s ===========\n",[self CBUUIDToString:service.UUID]);    if (!error) {        NSLog(@"=========== %d Characteristics of service ",service.characteristics.count);                for(CBCharacteristic *c in service.characteristics){                        NSLog(@" %s \n",[ self CBUUIDToString:c.UUID]);          //  CBService *s = [peripheral.services objectAtIndex:(peripheral.services.count - 1)];            if(service.UUID == NULL || s.UUID == NULL) return; // zach ios6 added                                                 //Register notification            if ([service.UUID isEqual:[CBUUID UUIDWithString:@"180D"]])                            {                if ([c.UUID isEqual:[CBUUID UUIDWithString:@"2A37"]])                {                    [self notification:service.UUID characteristicUUID:c.UUID peripheral:peripheral on:YES];                    NSLog(@"registered notification 2A37");                }                if ([c.UUID isEqual:[CBUUID UUIDWithString:@"2A38"]])                {                    [self notification:service.UUID characteristicUUID:c.UUID peripheral:peripheral on:YES];                    NSLog(@"registered notification 2A38");                }                if ([c.UUID isEqual:[CBUUID UUIDWithString:@"2A39"]])                {                    [self notification:service.UUID characteristicUUID:c.UUID peripheral:peripheral on:YES];                    NSLog(@"registered notification 2A39");                }                            }                    }        NSLog(@"=== Finished set notification ===\n");    }    else {        NSLog(@"Characteristic discorvery unsuccessfull !\n");    }    if([self compareCBUUID:service.UUID UUID2:s.UUID]) {//利用此來確定整個流程都結束後才能設定通知        [delegate didConnected:peripheral error:error];        NSLog(@"=== Finished discovering characteristics ===\n");        //全部服務都讀取完畢時才能使用！            }}

例子是以Heart Rate(180D)

Heart Rate來說，0x2A37可以得到心跳的數據，所以針對此項可以註冊通知來得到每次的心跳數據更新。

notification是我自行撰寫的Method，可以從Service UUID及Characteristic UUID來找到Service與Characteristic的Object Point，才可以符合註冊通知的格式

    [(CBPeripheral *)p setNotifyValue:(BOOL) forCharacteristic:CBCharacteristic *)]

將Characteristic的Point傳入並設定setNotifyValue:on就完成註冊通知，之後如果有更新資料時就會引發didUpdateValueForCharacteristic Delegate，再進行資料處理。

• notification

notification可以直接copy下程式碼重覆使用相當方便。

-(void) notification:(CBUUID *) serviceUUID characteristicUUID:(CBUUID *)characteristicUUID peripheral:(CBPeripheral *)p on:(BOOL)on {        CBService *service = [self getServiceFromUUID:serviceUUID p:p];    if (!service) {        if (p.UUID == NULL) return; // zach ios6 addedche        NSLog(@"Could not find service with UUID on peripheral with UUID \n");        return;    }    CBCharacteristic *characteristic = [self getCharacteristicFromUUID:characteristicUUID service:service];    if (!characteristic) {        if (p.UUID == NULL) return; // zach ios6 added        NSLog(@"Could not find characteristic with UUID  on service with UUID  on peripheral with UUID\n");        return;    }    [p setNotifyValue:on forCharacteristic:characteristic];}-(CBService *) getServiceFromUUID:(CBUUID *)UUID p:(CBPeripheral *)p {        for (CBService* s in p.services){        if ([self compareCBUUID:s.UUID UUID2:UUID]) return s;    }    return nil; //Service not found on this peripheral}-(CBCharacteristic *) getCharacteristicFromUUID:(CBUUID *)UUID service:(CBService*)service {        for (CBCharacteristic* c in service.characteristics){        if ([self compareCBUUID:c.UUID UUID2:UUID]) return c;    }    return nil; //Characteristic not found on this service}

didUpdateValueForCharacteristic

didUpdateValueForCharacteristic在連線完成後顯的非常重要，範例中有比對2個UUID為2A37與2A38

-(void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{    if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:@"2A37"]])    {        if( (characteristic.value)  || !error )        {        }    }        if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:@"2A38"]])    {        //set refresh int        uint8_t val = 1;        NSData* valData = [NSData dataWithBytes:(void*)&val length:sizeof(val)];        [peripheral writeValue:valData forCharacteristic:characteristic type:CBCharacteristicWriteWithResponse];    }    }

針對這兩個UUID成立時做對應的工作，這裡以2A38來解說一下。

• 2A38

從程式中的2A38來說，當更新資料為2A38時，程式將直接寫入 1 ，也就是在下表中可以了解到，1所代表的就是Chest

意思是告訴心跳感測器量測的位置是在胸部的部分。