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(@" Discover New Devices! "); NSLog(@"BLEInfo UUID:%@ RSSI:%@ ",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 1; } - (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(@" >>>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(@" >>> 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(@" FindtheValueis (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(@" Find---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(@" 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]%2!=0) { return nil; } Byte tempbyt[1]={0}; NSMutableData* bytes=[NSMutableData data]; for(int i=0;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 >= '0' && hex_char1 <='9') int_ch1 = (hex_char1-48)*16; //// 0 的Ascll - 48 else if(hex_char1 >= 'A' && hex_char1 <='F') int_ch1 = (hex_char1-55)*16; //// 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 >= '0' && hex_char2 <='9') int_ch2 = (hex_char2-48); //// 0 的Ascll - 48 else if(hex_char2 >= 'A' && hex_char2 <='F') int_ch2 = hex_char2-55; //// A 的Ascll - 65 else return nil; tempbyt[0] = int_ch1+int_ch2; ///将转化后的数放入Byte数组里 [bytes appendBytes:tempbyt length:1]; } 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 * 2)]; for(int i = 0; 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:@"11"]; }else{ [self writeToPeripheral:@"10"]; } } @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