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其他-使用gatttool从蓝牙温度计读取数据

(其他 - reading data from bluetooth thermometer with gatttool)

发布于 2020-11-27 16:04:40

我偶然发现了一个问题:使用Bluez Bluetooth Low Energy读取温度计数据, 并且正在尝试从我获得的蓝牙温度计读取数据。

我能够使用以下命令提取并读取所有句柄:

gatttool -b 00:11:22:33:44:55 -I
[00:11:22:33:44:55][LE]> connect
Connection successful
[00:11:22:33:44:55][LE]> primary
attr handle: 0x0001, end grp handle: 0x0007 uuid: 00001800-0000-1000-8000-00805f9b34fb
attr handle: 0x0008, end grp handle: 0x000b uuid: 00001801-0000-1000-8000-00805f9b34fb
attr handle: 0x000c, end grp handle: 0x001e uuid: 0000180a-0000-1000-8000-00805f9b34fb
attr handle: 0x001f, end grp handle: 0xffff uuid: 0000ffe0-0000-1000-8000-00805f9b34fb
[00:11:22:33:44:55][LE]> char-desc 0x0001 0x0001
handle: 0x0001, uuid: 00002800-0000-1000-8000-00805f9b34fb
[00:11:22:33:44:55][LE]> char-desc 0x0001 0x0007
handle: 0x0001, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0002, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0003, uuid: 00002a00-0000-1000-8000-00805f9b34fb
handle: 0x0004, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0005, uuid: 00002a01-0000-1000-8000-00805f9b34fb
handle: 0x0006, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0007, uuid: 00002a04-0000-1000-8000-00805f9b34fb
[00:11:22:33:44:55][LE]> char-read-hnd 01
Characteristic value/descriptor: 00 18 
[00:11:22:33:44:55][LE]> char-read-hnd 02
Characteristic value/descriptor: 02 03 00 00 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 03
Characteristic value/descriptor: 54 68 65 72 6d 6f 42 65 61 63 6f 6e 
[00:11:22:33:44:55][LE]> char-read-hnd 04
Characteristic value/descriptor: 02 05 00 01 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 05
Characteristic value/descriptor: 00 00 
[00:11:22:33:44:55][LE]> char-read-hnd 06
Characteristic value/descriptor: 02 07 00 04 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 07
Characteristic value/descriptor: 50 00 a0 00 00 00 e8 03 
[00:11:22:33:44:55][LE]> char-desc 0x0008 0x000b
handle: 0x0008, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0009, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x000a, uuid: 00002a05-0000-1000-8000-00805f9b34fb
handle: 0x000b, uuid: 00002902-0000-1000-8000-00805f9b34fb
[00:11:22:33:44:55][LE]> char-read-hnd 08
Characteristic value/descriptor: 01 18 
[00:11:22:33:44:55][LE]> char-read-hnd 09
Characteristic value/descriptor: 20 0a 00 05 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 0a
Error: Characteristic value/descriptor read failed: Attribute can't be read
[00:11:22:33:44:55][LE]> char-read-hnd 0b
Characteristic value/descriptor: 00 00 
[00:11:22:33:44:55][LE]> char-desc 0x000c 0x001e
handle: 0x000c, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x000d, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x000e, uuid: 00002a23-0000-1000-8000-00805f9b34fb
handle: 0x000f, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0010, uuid: 00002a24-0000-1000-8000-00805f9b34fb
handle: 0x0011, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0012, uuid: 00002a25-0000-1000-8000-00805f9b34fb
handle: 0x0013, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0014, uuid: 00002a26-0000-1000-8000-00805f9b34fb
handle: 0x0015, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0016, uuid: 00002a27-0000-1000-8000-00805f9b34fb
handle: 0x0017, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0018, uuid: 00002a28-0000-1000-8000-00805f9b34fb
handle: 0x0019, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x001a, uuid: 00002a29-0000-1000-8000-00805f9b34fb
handle: 0x001b, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x001c, uuid: 00002a2a-0000-1000-8000-00805f9b34fb
handle: 0x001d, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x001e, uuid: 00002a50-0000-1000-8000-00805f9b34fb
[00:11:22:33:44:55][LE]> char-read-hnd 0c
Characteristic value/descriptor: 0a 18 
[00:11:22:33:44:55][LE]> char-read-hnd 0d
Characteristic value/descriptor: 02 0e 00 23 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 0e
Characteristic value/descriptor: 5e 0b 00 00 00 00 f4 00 
[00:11:22:33:44:55][LE]> char-read-hnd 0f
Characteristic value/descriptor: 02 10 00 24 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 10
Characteristic value/descriptor: 4d 6f 64 65 6c 20 4e 75 6d 62 65 72 
[00:11:22:33:44:55][LE]> char-read-hnd 11
Characteristic value/descriptor: 02 12 00 25 2a
[00:11:22:33:44:55][LE]> char-read-hnd 12
Characteristic value/descriptor: 53 65 72 69 61 6c 20 4e 75 6d 62 65 72 
[00:11:22:33:44:55][LE]> char-read-hnd 13
Characteristic value/descriptor: 02 14 00 26 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 14
Characteristic value/descriptor: 46 69 72 6d 77 61 72 65 20 52 65 76 69 73 69 6f 6e 
[00:11:22:33:44:55][LE]> char-read-hnd 15
Characteristic value/descriptor: 02 16 00 27 2a 
[00:11:22:33:44:55][LE]> char-read-hnd 16

其中一些例如在将HEX转换为ASCII转换器时逐个4d 61 6e 75 66 61 63 74 75 72 65 72 20 4e 61 6d 65读取Manufacturer Name字母,但是其中一些例如02 1c 00 2a 2a read **具有一些空白方块

我还尝试将一些数字转换为十进制以尝试获取温度值,但是没有运气。

每次读取它们时,这些值都保持不变,所以我猜这是无法读取温度值的方法。

我是否必须以某种方式从那些句柄中请求该数据。如何从上面的数据中找到温度值?

当我读到这个温度是从19.8到20.2°C时,就像这样(如果它藏在我上面列出的那些值中的某个地方)

我只想从中读出温度值。

更新:

开启后scan onbluetoothctl我从蓝牙温度计收到了这个数据包:

[CHG] Device 00:11:22:33:44:55 RSSI: -81
[CHG] Device 00:11:22:33:44:55 TxPower: 0
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 24 0c 43 01 75 04 f3 5b  ..^.....$.C.u..[
  01 00                                            ..              
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 23 0c 43 01 79 04 02 5c  ..^.....#.C.y..\
  01 00                                            ..              
[CHG] Device 00:11:22:33:44:55 RSSI: -63
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 8c 01 2a 3d 00 00 34 01  ..^.......*=..4.
  c3 40 01 00                                      .@..            
[CHG] Device 00:11:22:33:44:55 RSSI: -81
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 24 0c 44 01 75 04 22 5c  ..^.....$.D.u."\
  01 00                                            ..              
[CHG] Device 00:11:22:33:44:55 RSSI: -54
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 8c 01 2a 3d 00 00 34 01  ..^.......*=..4.
  c3 40 01 00

让我们获取第一组数据:

[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
      00 00 55 44 33 22 11 00 24 0c 43 01 75 04 f3 5b  ..^.....$.C.u..[
      01 00

通过跳过设备的前2个字节55 44 33 22 11 00MAC地址,我注意到了,但是相反。

之后,该24 0c部分在其他集合中类似地重复,例如在下一个它中23 0c

接下来的2个字节(43 01)是我注意到房间温度变化时所改变的字节,并且是代表温度的字节。这是我计算温度的方法。反向的字节顺序- > 01 43- > 0x0143- >323以十进制- > 323/16- >20.1875其被20.2上舍入。这是温度计上的准确温度,当温度越来越高时我尝试了它,它始终显示准确的温度。

同样,接下来的两个75 040x0475->1141十进制-> 1141/16=71.3125向下舍入为71%->温度计上显示的湿度

这是正确的解释吗?

让我感到困惑的是第三组数据更长,并且数据包在这两组数据之间交替出现:

[CHG] Device 00:11:22:33:44:55 RSSI: -63
[CHG] Device 00:11:22:33:44:55 ManufacturerData Key: 0x0011
[CHG] Device 00:11:22:33:44:55 ManufacturerData Value:
  00 00 55 44 33 22 11 00 8c 01 2a 3d 00 00 34 01  ..^.......*=..4.
  c3 40 01 00

温度计还在发送其他一些数据吗?

Questioner
cheshire
Viewed
11
ukBaz 2020-11-30 03:24:53

附带说明一下,不建议使用gatttool,并且当前支持的工具是bluetoothctl

GATT UUID的格式为0000xxxx-0000-1000-8000-00805f9b34fb表示它们已被Bluetooth SIG采用,你可以在16位UUID编号文档中查找它们所代表的含义

还有一些通用的蓝牙低功耗扫描和探索工具,例如nRF connect,可以帮助你探索设备。

从你发布的GATT信息中,我只能看到需要包括的常规内容,而没有任何关于温度的特定信息。

广告数据包括制造商数据,制造商数据可以是制造商想要的任何东西(可能顾名思义)。来自核心规范补充

在此处输入图片说明

这意味着你需要从制造商那里获取信息,或者从你认为数据所说的内容中倒退。由于你尚未共享有关设备广播的任何信息,因此你似乎在朝着正确的方向前进。

大多数蓝牙数据都是低位字节序的,因此不必在周围交换字节就不足为奇了。像iBeacon和Eddystone这样的Beacon格式通常是大字节序,但它们是例外,而不是规则。

如果要将数据转换为某种代码,则可能需要使用D-Bus API。大多数语言都有D-Bus绑定,并且你需要的BlueZ API记录在: