[iOS 基于CoreBluetooth的蓝牙4.0通讯]

一、首先大致介绍下蓝牙4.0的模式，中心和周边：

一般情况下，iPhone作为中心，接收来自周边传感器（比如手环等）采集的数据。

二、那整一个数据通讯的协议是怎样的呢？

为什么要一层层搞这么复杂呢？据我的理解是这样的：

　　（1）蓝牙2.0的通讯非常简单，只有数据接收和发送，这样产生的问题就是：假如我有2个传感器的数据，但传输通道就一个，就发送时必须自己切割字符串等。

　　　   但4.0根据不同的功能，有点像传输分了很多“通道”，比如传感器1传输温度，服务的UUID是FFF0，然后特征字节发送的UUID为FFF1；传感器2传输距离，服务的UUID也是FFF0，但是特征字节发送的UUID为FFF2，这样就可以各取所需了，而不是蓝牙2.0那样一股脑儿收进来再切割。

　　（2）蓝牙4.0的每个“通道”都可以定义为发送或者接收字节，所以可以把发送和接收区分开。

　　补充：一般情况下，服务(Service)的UUID根据功能来区分（假如有FFF0和FFFE0两种服务），比如FFF0的服务ID里的特征字节UUID通道用来作为传感器通讯，FFE0里放蓝牙设备的信息，名称啊电池啊等等。。

三、代码：

1.BLEInfo.h(存放周边蓝牙设备的信息)

#import <Foundation/Foundation.h>
#import <CoreBluetooth/CoreBluetooth.h>
@interface BLEInfo : NSObject

@property (nonatomic, strong) CBPeripheral *discoveredPeripheral;
@property (nonatomic, strong) NSNumber *rssi;

@end

BLEInfo.m

#import "BLEInfo.h"

@implementation BLEInfo

@end

2.RootTableViewController.h（显示周边蓝牙信息，主要用scan函数就行了）

#import <UIKit/UIKit.h>
#import <CoreBluetooth/CoreBluetooth.h>
#import "BLEInfo.h"
#import "DetailViewController.h"
@interface RootTableViewController : UITableViewController<CBCentralManagerDelegate>

@property (nonatomic, strong) CBCentralManager *centralMgr;
@property (nonatomic, strong) NSMutableArray *arrayBLE;

@end

RootTableViewController.m

#import "RootTableViewController.h"

@interface RootTableViewController ()

@end

@implementation RootTableViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.title=@"蓝牙搜索";
    self.centralMgr = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
    self.arrayBLE = [[NSMutableArray alloc] init];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

//蓝牙状态delegate
- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
    switch (central.state)
    {
        case CBCentralManagerStatePoweredOn:
            [self.centralMgr scanForPeripheralsWithServices:nil options:nil];
            NSLog(@"start scan Peripherals");

            break;

        default:
            NSLog(@"Central Manager did change state");
            break;
    }
}

//发现设备delegate
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
{
    BLEInfo *discoveredBLEInfo = [[BLEInfo alloc] init];
    discoveredBLEInfo.discoveredPeripheral = peripheral;
    discoveredBLEInfo.rssi = RSSI;

    // update tableview
    [self saveBLE:discoveredBLEInfo];

}

//保存设备信息
- (BOOL)saveBLE:(BLEInfo *)discoveredBLEInfo
{
    for (BLEInfo *info in self.arrayBLE)
    {
        if ([info.discoveredPeripheral.identifier.UUIDString isEqualToString:discoveredBLEInfo.discoveredPeripheral.identifier.UUIDString])
        {
            return NO;
        }
    }

    NSLog(@"\nDiscover New Devices!\n");
    NSLog(@"BLEInfo\n UUID：%@\n RSSI:%@\n\n",discoveredBLEInfo.discoveredPeripheral.identifier.UUIDString,discoveredBLEInfo.rssi);

    [self.arrayBLE addObject:discoveredBLEInfo];
    [self.tableView reloadData];
    return YES;
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    // Return the number of sections.
    return ;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    return _arrayBLE.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"cell"];

    // Step 2: If there are no cells to reuse, create a new one
    if(cell == nil) cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"cell"];
    // Add a detail view accessory
    BLEInfo *thisBLEInfo=[self.arrayBLE objectAtIndex:indexPath.row];
    cell.textLabel.text=[NSString stringWithFormat:@"%@ %@",thisBLEInfo.discoveredPeripheral.name,thisBLEInfo.rssi];
    cell.detailTextLabel.text=[NSString stringWithFormat:@"UUID:%@",thisBLEInfo.discoveredPeripheral.identifier.UUIDString];
    // Step 3: Set the cell text

    // Step 4: Return the cell
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{

    BLEInfo *thisBLEInfo=[self.arrayBLE objectAtIndex:indexPath.row];
    DetailViewController* dtvc=[self.storyboard instantiateViewControllerWithIdentifier:@"DetailViewController"];
    dtvc.centralMgr=self.centralMgr;
    dtvc.discoveredPeripheral=thisBLEInfo.discoveredPeripheral;

    [self.navigationController pushViewController:dtvc animated:YES];

}
@end

3.DetailViewController.h（连接具体的蓝牙，发现其内部信息）

#import <UIKit/UIKit.h>
#import <CoreBluetooth/CoreBluetooth.h>

@interface DetailViewController : UIViewController<
CBPeripheralManagerDelegate,
CBCentralManagerDelegate,
CBPeripheralDelegate
>

@property (nonatomic, strong) CBCentralManager *centralMgr;
@property (nonatomic, strong) CBPeripheral *discoveredPeripheral;
@property (strong, nonatomic) CBCharacteristic* writeCharacteristic;

@property int current_humitidy;
@property int current_temperature;

- (IBAction)led1control:(id)sender;

@end

DetailViewController.m

#import "DetailViewController.h"

@interface DetailViewController ()

@end

@implementation DetailViewController

#define SECTION_NAME @"Serviceinfo"

- (void)viewDidLoad
{
    [super viewDidLoad];

    [_centralMgr setDelegate:self];
    if (_discoveredPeripheral)
    {
        NSLog(@"connectPeripheral");
        [_centralMgr connectPeripheral:_discoveredPeripheral options:nil];
    }
}

//界面退出
-(void)viewWillDisappear:(BOOL)animated{
    [self.centralMgr cancelPeripheralConnection:_discoveredPeripheral];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
//========================================================================================
//0.假设蓝牙关闭、掉线什么的，重新搜索
- (void)centralManagerDidUpdateState:(CBCentralManager *)central
{
    switch (central.state)
    {
        case CBCentralManagerStatePoweredOn:
            //[self.centralMgr scanForPeripheralsWithServices:nil options:nil];
            NSLog(@"start scan Peripherals");

            break;

        default:
            NSLog(@"Central Manager did change state");
            break;
    }
}

//1.搜索后重连
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
{
    //[_centralMgr connectPeripheral:_discoveredPeripheral options:nil];
}
//========================================================================================
*/

//2.连接的Delegate 连接若成功则搜索服务
- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
    NSLog(@"didFailToConnectPeripheral : %@", error.localizedDescription);
}

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

    [_discoveredPeripheral setDelegate:self];

    //查找服务
    [_discoveredPeripheral discoverServices:nil];
}

//========================================================================================
//3.搜索服务的Delegate 若发现服务，然后搜索其内的特征服务

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
{
    if (error)
    {
        NSLog(@"didDiscoverServices : %@", [error localizedDescription]);
        //        [self cleanup];
        return;
    }

    for (CBService *s in peripheral.services)
    {
        NSLog(@"\n>>>服务UUID found with UUID : %@ des:%@", s.UUID,s.UUID.description);
        //查找特征字节
        [s.peripheral discoverCharacteristics:nil forService:s];
    }
}
//========================================================================================
//4.搜索特征的Delegate 若发现特征，则看看这个“通道是发送的还是接收”，接收就read，发送就把这个writeCharacteristic记录下
//注意：不是所有的特性值都是可读的（readable）。通过访问 CBCharacteristicPropertyRead 可以知道特性值是否可读。如果一个特性的值不可读，使用 peripheral:didUpdateValueForCharacteristic:error:就会返回一个错误。
//Subscribing to a Characteristic’s Value(订制一个特性值) 尽管通过 readValueForCharacteristic:方法能够得到特性值，但是对于一个变化的特性值就不是很 有效了。大多数的特性值是变化的，比如一个心率监测应用，如果需要得到特性值，就需要 通过预定的方法获得。当预定了一个特性值，当值改变时，就会收到设备发出的通知。

/*特征值的属性：c.properties
 typedef NS_OPTIONS(NSInteger, CBCharacteristicProperties) {
 // 标识这个characteristic的属性是广播
 CBCharacteristicPropertyBroadcast= 0x01,
 // 标识这个characteristic的属性是读
 CBCharacteristicPropertyRead= 0x02,
 // 标识这个characteristic的属性是写-没有响应
 CBCharacteristicPropertyWriteWithoutResponse= 0x04,
 // 标识这个characteristic的属性是写
 CBCharacteristicPropertyWrite= 0x08,
 // 标识这个characteristic的属性是通知
 CBCharacteristicPropertyNotify= 0x10,
 // 标识这个characteristic的属性是声明
 CBCharacteristicPropertyIndicate= 0x20,
 // 标识这个characteristic的属性是通过验证的
 CBCharacteristicPropertyAuthenticatedSignedWrites= 0x40,
 // 标识这个characteristic的属性是拓展
 CBCharacteristicPropertyExtendedProperties= 0x80,
 // 标识这个characteristic的属性是需要加密的通知
 CBCharacteristicPropertyNotifyEncryptionRequiredNS_ENUM_AVAILABLE(NA, 6_0)= 0x100,
 // 标识这个characteristic的属性是需要加密的申明
 CBCharacteristicPropertyIndicateEncryptionRequiredNS_ENUM_AVAILABLE(NA, 6_0)= 0x200
 };
 */
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
{
    if (error)
    {
        NSLog(@"didDiscoverCharacteristicsForService error : %@", [error localizedDescription]);
        return;
    }

    for (CBCharacteristic *c in service.characteristics)
    {
        NSLog(@"\n>>>\t特征UUID FOUND(in 服务UUID:%@): %@ (data:%@)",service.UUID.description,c.UUID,c.UUID.data);

        /*
        根据特征不同属性去读取或者写
        if (c.properties==CBCharacteristicPropertyRead) {
        }
        if (c.properties==CBCharacteristicPropertyWrite) {
        }
        if (c.properties==CBCharacteristicPropertyNotify) {
        }
        */

        //假如你和硬件商量好了，某个UUID时写，某个读的，那就不用判断啦
        /*
        if([c.UUID isEqual:[CBUUID UUIDWithString:@"FFF1"]]){
            self.writeCharacteristic = c;
        }
        if([c.UUID isEqual:[CBUUID UUIDWithString:@"FFF6"]]){
            [peripheral readValueForCharacteristic:c];
        }*/
        if (c.properties==CBCharacteristicPropertyRead) {
            [peripheral readValueForCharacteristic:c];
        }
    }
}
//========================================================================================

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
{
    if (error)
    {
        NSLog(@"didUpdateValueForCharacteristic error : %@", error.localizedDescription);
        return;
    }

    NSLog(@"\nFindtheValueis (UUID:%@):%@ ",characteristic.UUID,characteristic.value);

    /*
    if([characteristic.UUID.description isEqualToString:@"FFF6"]){
        //我这里采用的是16进制数据，如<34001a00>，3400代表湿度十进制52.0，1a00代表温度26.0
        //当然你也可以有自己定义传输字符的意义
        NSData *datavalue=characteristic.value;
        NSData *shidudata=[datavalue subdataWithRange:NSMakeRange(0, 1)];
        NSData *wendudata=[datavalue subdataWithRange:NSMakeRange(2, 1)];
        NSLog(@"\nFind---theValueis:%@   %@-%@",characteristic.value,shidudata,wendudata);
        int i=0,j=0;
        [shidudata getBytes: &i length: sizeof(i)];
        [wendudata getBytes: &j length: sizeof(j)];

        self.current_humitidy=i;
        self.current_temperature=j;

        NSLog(@"\n室内温度为：%d℃，室内湿度为：%d%%",_current_temperature,_current_humitidy);
    }
    */
}

- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    if (error) {
        NSLog(@"Error changing notification state: %@", [error localizedDescription]);
    }
}

//向peripheral中写入数据后的回调函数
- (void)peripheral:(CBPeripheral*)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{
    NSLog(@"write value success : %@", characteristic);
}

//自定义的写入数据的函数
- (void)writeToPeripheral:(NSString *)string{
    if(!_writeCharacteristic){
        NSLog(@"writeCharacteristic is nil!");
        return;
    }

    NSData* value = [self stringToByte:string];
    NSLog(@"Witedata: %@",value);

    [_discoveredPeripheral writeValue:value forCharacteristic:_writeCharacteristic type:CBCharacteristicWriteWithResponse];
}

//====================================================================================================
//一些转换函数，本例中只用到stringToByte
-(NSData*)stringToByte:(NSString*)string
{
    NSString *hexString=[[string uppercaseString] stringByReplacingOccurrencesOfString:@" " withString:@""];
    if ([hexString length]%!=) {
        return nil;
    }
    Byte tempbyt[]={};
    NSMutableData* bytes=[NSMutableData data];
    for(int i=;i<[hexString length];i++)
    {
        unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)
        int int_ch1;
        if(hex_char1 >= '' && hex_char1 <='')
            int_ch1 = (hex_char1-)*;   //// 0 的Ascll - 48
        else if(hex_char1 >= 'A' && hex_char1 <='F')
            int_ch1 = (hex_char1-)*; //// A 的Ascll - 65
        else
            return nil;
        i++;

        unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
        int int_ch2;
        if(hex_char2 >= '' && hex_char2 <='')
            int_ch2 = (hex_char2-); //// 0 的Ascll - 48
        else if(hex_char2 >= 'A' && hex_char2 <='F')
            int_ch2 = hex_char2-; //// A 的Ascll - 65
        else
            return nil;

        tempbyt[] = int_ch1+int_ch2;  ///将转化后的数放入Byte数组里
        [bytes appendBytes:tempbyt length:];
    }
    return bytes;
}

//NSData类型转换成NSString
- (NSString*)hexadecimalString:(NSData *)data{
    NSString* result;
    const unsigned char* dataBuffer = (const unsigned char*)[data bytes];
    if(!dataBuffer){
        return nil;
    }
    NSUInteger dataLength = [data length];
    NSMutableString* hexString = [NSMutableString stringWithCapacity:(dataLength * )];
    for(int i = ; i < dataLength; i++){
        [hexString appendString:[NSString stringWithFormat:@"%02lx", (unsigned long)dataBuffer[i]]];
    }
    result = [NSString stringWithString:hexString];
    return result;
}
//====================================================================================================

//假设有个swt1,开一下发送一个开关信号，控制LED灯
- (IBAction)led1control:(id)sender {
    UISwitch *swt1= (UISwitch*)sender;
    if (swt1.on) {
        [self writeToPeripheral:@""];
    }else{
        [self writeToPeripheral:@""];

    }
}

@end

完整代码地址：https://github.com/rayshen/ShenBLETest

四、示例：基于蓝牙4.0的温湿度采集控制器

这是我自己做的湿度和温度的收集器和控制器。

iPhone收集来自单片机（蓝牙CC2541芯片）的温度和湿度信息，并且可以控制LED灯和继电器。

继电器就是一个开关，外围可以连接其他带电源和电器的大电路。

欢迎大家和我交流，我的微博是：weibo.com/rayshen1012