get data from dht, co2 meter and noise level sensor

stats_relay.py

import paho.mqtt.client as mqtt
import Adafruit_DHT
import usb.core
import statistics
import requests
import sdnotify
import sys, fcntl, time, os, argparse, socket
from time import sleep

delay = 5
broker = "kitchenpi.lan"
lwt = "alive/stats_relay"
topic = "stats"

n = sdnotify.SystemdNotifier()

h = []
t = []
s = []

buffer_size = 5
min_deviation = 5

def app(list, val):
    if len(list) < buffer_size:
        list.append(val)
        return val
    else:
        #return last sample if val is weird outlier
        std_dev = statistics.stdev(list)
        if abs(statistics.mean(list) - val) > (std_dev * 2 + min_deviation) :
            return list[len(list)-1]
        else:
            list.pop(0)
            list.append(val)
            return val


dev = usb.core.find(idVendor=0x16c0, idProduct=0x5dc)

def on_connect(client, userdata, flags, rc):
    if rc == 3:
        print("Server unavailable")
        on_disconnect(client, userdata, rc)
        return

    print("connected to mqtt broker")
    client.will_set(lwt, "dead", QOS1, retain=True)

client = mqtt.Client("stats_relay")
client.on_connect = on_connect
client.connect(broker, 1883,60)
client.loop_start()


def notify():
    requests.get(url = "https://hc-ping.com/53816436-ddba-490d-b113-8a7d9017c629")
    n.notify("WATCHDOG=1")


def decrypt_co2(key,  data):
    cstate = [0x48,  0x74,  0x65,  0x6D,  0x70,  0x39,  0x39,  0x65]
    shuffle = [2, 4, 0, 7, 1, 6, 5, 3]

    phase1 = [0] * 8
    for i, o in enumerate(shuffle):
        phase1[o] = data[i]

    phase2 = [0] * 8
    for i in range(8):
        phase2[i] = phase1[i] ^ key[i]

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

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

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

    return out

def stat_loop():

    key = [0xc4, 0xc6, 0xc0, 0x92, 0x40, 0x23, 0xdc, 0x96]
    fp = open("/dev/hidraw0", "a+b",  0)
    HIDIOCSFEATURE_9 = 0xC0094806
    set_report = "\x00" + "".join(chr(e) for e in key)
    fcntl.ioctl(fp, HIDIOCSFEATURE_9, set_report)

    values = {}

    data_encrypted_print = False

    while(1):
            data = list(ord(e) for e in fp.read(8))
            if data[4] == 0x0d and (sum(data[:3]) & 0xff) == data[3]:
                decrypted = data
                if data_encrypted_print == False:
                    print "Info: data not encrypted"
                    data_encrypted_print = True
            else:
                decrypted = decrypt(key, data)
            if decrypted[4] != 0x0d or (sum(decrypted[:3]) & 0xff) != decrypted[3]:
                print "co2 device Checksum error"
            else:
                op = decrypted[0]
                val = decrypted[1] << 8 | decrypted[2]
                values[op] = val

                if (0x50 in values) and (0x42 in values):
                    co2 = values[0x50]
                    tmp = (values[0x42]/16.0-273.15)
                    client.publish(topic + "/co2", co2)
                    client.publish(topic + "/co2_temp", tmp)
                    print "co2: ", co2, " co2_temp : ", tmp

            humidity, temperature = Adafruit_DHT.read_retry(Adafruit_DHT.DHT22, 18)
            print "raw dht22 temperature: ", temperature, " humidity : ", humidity
            humidity = app(h, humidity)
            temperature = app(t, temperature)
            client.publish(topic + "/humidity", humidity)
            client.publish(topic + "/temperature", temperature)

            ret = dev.ctrl_transfer(0xC0, 4, 0, 0, 200)
            dB = (ret[0] + ((ret[1] & 3) * 256)) * 0.1 + 30

            client.publish(topic + "/raw_sound_level", dB)
            s.append(dB)
            if len(s) > buffer_size:
                s.pop(0)

            dB = statistics.mean(s)

            client.publish(topic + "/sound_level", dB)

            print "dht22 temperature: ", temperature, " humidity : ", humidity, " db level: ", dB
            notify()
            sleep(delay)

stat_loop()