BLE rssi catcher

neurolinker.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import atexit
import bluetooth._bluetooth as bluez
import struct
import subprocess

from time import time
from threading import Timer


MAC_ADDR = struct.pack('6B', 0xc7, 0x51, 0x14, 0xd6, 0xc5, 0xc9)

SCAN_ENABLE = struct.pack('2B', 0x01, 0x00)
SCAN_DISABLE = struct.pack('2B', 0x00, 0x00)
SCAN_OPT = struct.pack('7B', 0x01, 0x10, 0x00, 0x10, 0x00, 0x00, 0x00)

class NeuroLinker:
    def __init__(self):
        self.S = bluez.hci_open_dev(0)
        self.L = False
        self.C = 0
        self.LT = time()
        atexit.register(self.bye)

        self.tick()
        self.main()

    def set_screenlock(self, lock):
        self.L = lock
        subprocess.call(['sudo', '-u', 'devunt', '/usr/bin/gnome-screensaver-command', '-l' if lock else '--exit'])

    def main(self):
        _scanner = self.scanner()
        while 1:
            rssi = _scanner.next()
            print 'rssi: {0} / C: {1}'.format(rssi, self.C)
            if self.L:
                if rssi >= -85: self.C += 1
                elif self.C > 0: self.C = 0
                if self.C >= 5:
                    self.C = 0
                    self.set_screenlock(False)
            else:
                if rssi < -85: self.C += 1
                elif self.C > 0: self.C = 0
                if self.C >= 5:
                    self.C = 0
                    self.set_screenlock(True)

    def tick(self):
        if (time() - self.LT > 10) and self.C > 0:
            self.C = 0
            self.set_screenlock(True)
        t = Timer(1, self.tick)
        t.daemon = True
        t.start()

    def scanner(self):
        bluez.hci_send_cmd(self.S, 0x08, 0x0b, SCAN_OPT)
        bluez.hci_send_cmd(self.S, 0x08, 0x0c, SCAN_ENABLE)

        ft = bluez.hci_filter_new()
        bluez.hci_filter_all_events(ft)
        bluez.hci_filter_set_ptype(ft, bluez.HCI_EVENT_PKT)
        self.S.setsockopt(bluez.SOL_HCI, bluez.HCI_FILTER, ft)

        while 1:
            pkt = self.S.recv(512)
            if pkt == '':
                break
            ptype, event, plen, subevent, num, evtype = struct.unpack('6B', pkt[:6])
            if (ptype == 0x04 and
                    event == 0x3e and
                    subevent == 0x02 and
                    evtype == 0x00 and
                    pkt[7:13] == MAC_ADDR):
                rssi = struct.unpack('b', pkt[-1])[0]
                self.LT = time()
                yield rssi

    def bye(self):
        bluez.hci_send_cmd(self.S, 0x08, 0x0c, SCAN_DISABLE)

def main():
    NeuroLinker()

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        exit(0)