mqtt-sensord/mqtt_sensord/sensorlib/misc_sensors.py

import fcntl
import random
import threading
import time

from .base import Sensor, sensor


@sensor
class FakeSensor(Sensor):
    sensor_class = 'fake'

    def __init__(self, **sensor_conf):
        super(FakeSensor, self).__init__(**sensor_conf)

    def get_data(self):
        return {'random': random.randint(0, 20)}


@sensor
class CO2Meter(Sensor):
    sensor_class = 'co2meter'
    HIDIOCSFEATURE_9 = 0xC0094806
    TEMP = 0x42
    CO2 = 0x50
    HUM = 0x44

    def __init__(self, dev_path, **sensor_conf):
        super(CO2Meter, self).__init__(**sensor_conf)

        self.dev_path = dev_path
        self.key = b'\x11\x11\x11\x11\x11\x11\x11\x11'
        self._dev = None
        self.values = {}

        self.init_meter()
        self.start()

    def init_meter(self):
        self._dev = open(self.dev_path, "a+b", 0)
        set_report = b'\x00' + self.key
        fcntl.ioctl(self._dev, self.HIDIOCSFEATURE_9, set_report)

    def decrypt(self, data):
        cstate = [0x48,  0x74,  0x65,  0x6D,  0x70,  0x39,  0x39,  0x65]
        shuffle = [2, 4, 0, 7, 1, 6, 5, 3]

        phase1 = bytearray(8)
        for i, o in enumerate(shuffle):
            phase1[o] = data[i]

        phase2 = bytearray(8)
        for i in range(8):
            phase2[i] = phase1[i] ^ self.key[i]

        phase3 = bytearray(8)
        for i in range(8):
            phase3[i] = (phase2[i] >> 3 | phase2[i - 1] << 5) & 0xff

        ctmp = bytearray(8)
        for i in range(8):
            ctmp[i] = (cstate[i] >> 4 | cstate[i] << 4) & 0xff

        out = bytearray(8)
        for i in range(8):
            out[i] = (0x100 + phase3[i] - ctmp[i]) & 0xff

        return out

    def start(self):
        self._stop = False
        self._worker_thread = threading.Thread(target=self._worker, daemon=True)
        self._worker_thread.start()

    def stop(self):
        self._stop = True
        self._worker_thread = None

    def _worker(self):
        while not self._stop:
            try:
                data = self._dev.read(8)
                decrypted = self.decrypt(data)
                if decrypted[4] == 0x0d and sum(decrypted[:3]) & 0xff == decrypted[3]:
                    op = decrypted[0]
                    val = decrypted[1] << 8 | decrypted[2]
                    self.values[op] = val
                else:
                    print("Error decrypting data:", data, '==>', decrypted)
            except (IOError, OSError) as e:
                print("Device error: {} - trying to reopen".format(e))
                self.values = {}
                try:
                     self._dev.close()
                except Exception:
                        pass
                while self._dev.closed:
                    time.sleep(1)
                    try:
                        self.init_meter()
                    except (IOError, OSError) as e:
                        print("Device error: {} - trying to reopen".format(e))


    def get_co2(self):
        if 0x50 in self.values:
            return self.values[0x50]
        return None

    def get_temp(self):
        if 0x42 in self.values:
            return self.values[0x42] / 16.0 - 273.15
        return None

    def get_humidity(self):
        if 0x44 in self.values:
            return self.values[0x44] / 100.0
        return None

    def get_data(self):
        return dict(temp=self.get_temp(), co2=self.get_co2())


if __name__ == '__main__':
    import argparse
    import time

    parser = argparse.ArgumentParser()
    parser.add_argument("device", help="Device do read from")
    args = parser.parse_args()

    co2 = CO2Meter(args.device)
    co2.start()
    try:
        while True:
            if co2.get_temp() and co2.get_co2():
                print("{:2.4}°C {:4} PPM CO2".format(co2.get_temp(), co2.get_co2()))
            time.sleep(2)
    except KeyboardInterrupt:
        pass