PyGatttool

A wrapper around gatttool and pexpect, intended to be used as a simple BLE development tool for interacting with peripheral devices.

Requirements

A working gatttool install.

If installing from the repo you need pexpect (pip install pexpect).

Installation

pip install pygatttool

Usage

The following code (from polarpy) starts the raw PPG stream on a Polar OH1. The address and attribute handles for your particular device can be found using gatttool or another BLE tool such as nRF Connect.

from pygatttool import PyGatttool

OH1_ADDR = "XX:XX:XX:XX:XX:XX"
OH1_CONTROL_ATTRIBUTE_HANDLE = 0xXX
OH1_DATA_ATTRIBUTE_HANDLE = 0xXX

if '__main__' == __name__:
    ble = PyGatttool(address=OH1_ADDR)

    ble.connect()
    ble.mtu(232)
    ble.char_write_req(handle=OH1_CONTROL_ATTRIBUTE_HANDLE + 1, value=0x200)
    ble.char_write_req(handle=OH1_DATA_ATTRIBUTE_HANDLE + 1, value=0x100)
    ble.char_write_cmd(handle=OH1_CONTROL_ATTRIBUTE_HANDLE, b'\x02\x01\x00\x01\x82\x00\x01\x01\x16\x00')

    while True:
        print(ble.wait_for_notification(handle=OH1_DATA_ATTRIBUTE_HANDLE))

the output will look something like this:

01 00 b2 92 28 f4 52 82 07 00 ce ff 03 71 54 05 f3 60 05 a8 f2 ff 30 00 04 c6 54 05 07 60 05 8a f2 ff 3a ff 03 8c 54 05 88 5f 05 65 f2 ff 97 ff 03 e4 54 05 04 5f 05 41 f2 ff 17 ff 03 d6 54 05 70 5e 05 18 f2 ff a7 ff 03 6d 54 05 4f 5e 05 4b f2 ff 78 ff 03 8b 54 05 5b 5e 05 0b f2 ff 3f 00 04 48 54 05 a0 5e 05 08 f2 ff 18 00 04 f3 54 05 ca 5e 05 13 f2 ff 93 ff 03 84 54 05 67 5f 05 08 f2 ff 26 00 04 66 55 05 f1 5e 05 34 f2 ff e0 ff 03 be 55 05 81 5f 05 0b f2 ff dc ff 03 b2 55 05 c1 5f 05 0b f2 ff 75 00 04 b5 56 05 2b 60 05 2c f2 ff a8 ff 03 a5 56 05 6b 60 05 d6 f1 ff 89 00 04 57 57 05 88 60 05 3a f2 ff d9 00 04 55 57 05 33 61 05 3b f2 ff 45 01 04 7f 57 05 a0 61 05 38 f2 ff 
01 00 b2 72 30 f4 52 82 07 00 4e 01 04 a0 58 05 f2 60 05 49 f1 ff a2 01 04 a6 58 05 28 62 05 3e f2 ff 5f 02 04 41 59 05 9a 62 05 37 f2 ff 16 02 04 1a 5a 05 34 63 05 4e f2 ff 43 02 04 1d 5a 05 1e 63 05 47 f2 ff 05 03 04 ea 5a 05 ba 63 05 3f f2 ff 18 03 04 aa 5a 05 93 64 05 4a f2 ff a7 03 04 b1 5b 05 82 64 05 e6 f1 ff 6f 03 04 ff 5b 05 47 65 05 0d f2 ff e3 03 04 3c 5c 05 47 65 05 51 f2 ff 7b 04 04 db 5c 05 d7 65 05 8d f2 ff 98 04 04 d6 5c 05 3a 66 05 45 f2 ff 38 05 04 d3 5d 05 b3 66 05 5b f2 ff 72 05 04 7d 5d 05 ea 66 05 9d f2 ff b4 05 04 b2 5e 05 3d 67 05 4c f2 ff 8f 05 04 4b 5e 05 57 67 05 61 f2 ff 3c 06 04 ca 5e 05 66 67 05 2d f2 ff fe 05 04 2e 5f 05 93 67 05 16 f2 ff 

...

Issues

• While readily available, gatttool is long deprecated.

• It is somewhat unfortunate that gatttool does not appear report a version number. The pexpect code is looking for specific response strings, so if those strings change even slightly between versions it will break PyGatttool. That being said, it has been tested on several versions of Ubuntu 20+ without any issues, and given the deprecation it is probably unlikely that it will change.