bl_battery.py

#!/usr/bin/env python3

#
# This script prints the battery charge level of some bluetooth headsets
# 

# License: GPL-3.0
# Author: @TheWeirdDev
# 29 Sept 2019

import socket, sys

def send(sock, message):
    print('>' + message.decode())
    sock.send(b"\r\n" + message + b"\r\n")

def getATCommand(sock, line):
    print('<' + line.decode())
    if b"BRSF" in line:
        send(sock, b"+BRSF:20")
        send(sock, b"OK")
    elif b"CIND=" in line:
        send(sock, b"+CIND: (\"battchg\",(0-5))")
        send(sock, b"OK")
    elif b"CIND?" in line:
        send(sock, b"+CIND: 5")
        send(sock, b"OK")
    elif b"IPHONEACCEV" in line:
        if not b',' in line:
            return True
        
        parts = line[line.index(b',') + 1 : -1].split(b',')
        if len(parts) < 1 or (len(parts) % 2) != 0:
            return True
        
        i = 0
        while i < len(parts):
            key = int(parts[i])
            val = int(parts[i + 1])
            
            if key == 1:
                blevel = (val + 1) * 10
                print("Battery level: {}%\n".format(blevel))
                return False
            i += 2
    else:
        send(sock, b"OK")
    return True

def main():
    if (len(sys.argv) < 2):
        print("Usage: bl_battery.py <BT_MAC_ADDRESS>")
        exit()
    
    BT_ADDRESS = sys.argv[1]
    
    s = socket.socket(socket.AF_BLUETOOTH, socket.SOCK_STREAM, socket.BTPROTO_RFCOMM)
    s.connect((BT_ADDRESS, 3))

    while getATCommand(s, s.recv(128)):
        pass
             
if __name__ == "__main__":
    main()