树莓派python扫描蓝牙

古城微笑少年丶 2023-02-28 05:54 8阅读 0赞

# 环境 #

树莓派3b+  
python3.7  
蓝牙设备

# pybluez库 #

github链接：https://github.com/pybluez/pybluez

*  安装库

sudo pip3 install pybluez

*  简单扫描

import bluetooth
    
    nearby_devices = bluetooth.discover_devices(lookup_names=True)
    print("Found {} devices.".format(len(nearby_devices)))
    
    for addr, name in nearby_devices:
        print("  {} - {}".format(addr, name))

能够正常运行，但只能扫描到手机。我用的是蓝牙卡片，手机扫描到的是在`其他设备`栏里，查找资料发现是属于`低功耗蓝牙设备ibeacon`。下面还有另一个官方示例，提示是扫描低功耗的，尝试一下。

*  低功耗扫描

from bluetooth.ble import DiscoveryService
    
    service = DiscoveryService()
    devices = service.discover(2)
    
    for address, name in devices.items():
        print("name: {}, address: {}".format(name, address))

运行后提示缺少`gattlib`库，由于该库依赖其他环境，找了半天解决方案还是有问题，于是放弃了，暂时只能做到扫描手机设备。

# bluepy库 #

github链接：https://github.com/IanHarvey/bluepy  
找到了另外一个蓝牙扫描库，能扫出低功耗的蓝牙设备。

*  安装库

sudo pip3 install bluepy

*  示例代码

from bluepy.btle import Scanner, DefaultDelegate
    
    class ScanDelegate(DefaultDelegate):
        def __init__(self):
            DefaultDelegate.__init__(self)
    
        def handleDiscovery(self, dev, isNewDev, isNewData):
            if isNewDev:
                print("Discovered device", dev.addr)
            elif isNewData:
                print("Received new data from", dev.addr)
    
    scanner = Scanner().withDelegate(ScanDelegate())
    devices = scanner.scan(10.0)
    print(len(devices))
    for dev in devices:
        print("---------------")
        print("Device %s (%s), RSSI=%d dB" % (dev.addr, dev.addrType, dev.rssi))
        for (adtype, desc, value) in dev.getScanData():
            print("  %s = %s" % (desc, value))

**其中`scanner.scan(10.0)`代表扫描时间**

*  扫描结果

---------------
    Device ac:23:3f:58:4e:ca (public), RSSI=-61 dB
      Flags = 06
      Manufacturer = 4c000215fda50693a4e24fb1afcfc6eb0764782527114cb9c5
      Tx Power = ec
      Complete 16b Services = 0000fda5-0000-1000-8000-00805f9b34fb
      16b Service Data = a5fd6427114cb9ac233f584eca
      Complete Local Name = axon_33
    ---------------
    Device ac:23:3f:58:4f:fd (public), RSSI=-86 dB
      Flags = 06
      Manufacturer = 4c000215fda50693a4e24fb1afcfc6eb0764782527114cb9c5
      Tx Power = ec
      Complete 16b Services = 0000fda5-0000-1000-8000-00805f9b34fb
      16b Service Data = a5fd6427114cb9ac233f584ffd
      Complete Local Name = axon_71

目前需求需要让设备持续扫描一段时间，将所有的蓝牙信息上报，为防止扫描遗漏，故需扫描时间延长到几十秒以上。

但发现若扫描时间过长，会报`bluepy.btle.BTLEDisconnectError: Device disconnected`错误。原因是某个蓝牙设备的断开而使程序发生错误了，于是想到开启额外线程循环扫描，每次扫描时间设为5秒，代码如下：

*  循环扫描

from bluepy.btle import Scanner, DefaultDelegate
    from multiprocessing import Process, Event
    
    
    class ScanDelegate(DefaultDelegate):
        def __init__(self):
            DefaultDelegate.__init__(self)
    
        def handleDiscovery(self, dev, isNewDev, isNewData):
            if isNewDev:
                print("Discovered device", dev.addr)
            elif isNewData:
                print("Received new data from", dev.addr)
    
    class BLEScanner:
        def __init__(self):
            self.scanner = Scanner().withDelegate(ScanDelegate())
    
            self.stop_event = Event()
    
        def start(self):
    
            self.stop_event.clear()
    
            self.process = Process(target=self.scan, args = ())
            self.process.start()
            return self
    
        def scan(self):
            while True:
                if self.stop_event.is_set():
                    return
                self.devices = self.scanner.scan(5, passive=True)
    
        def stop(self):
            self.stop_event.set()
    BLEScanner().start()

后续只要将mac地址扔到set集合中，收集一段时间后上报就行了。