127 lines
3.2 KiB
Python
127 lines
3.2 KiB
Python
#!/usr/bin/python
|
|
# coding=utf-8
|
|
# "DATASHEET": http://cl.ly/ekot
|
|
# https://gist.github.com/kadamski/92653913a53baf9dd1a8
|
|
from __future__ import print_function
|
|
import serial, struct, sys, time, json
|
|
|
|
DEBUG = 0
|
|
CMD_MODE = 2
|
|
CMD_QUERY_DATA = 4
|
|
CMD_DEVICE_ID = 5
|
|
CMD_SLEEP = 6
|
|
CMD_FIRMWARE = 7
|
|
CMD_WORKING_PERIOD = 8
|
|
MODE_ACTIVE = 0
|
|
MODE_QUERY = 1
|
|
|
|
ser = serial.Serial()
|
|
ser.port = "/dev/ttyUSB0"
|
|
ser.baudrate = 9600
|
|
|
|
ser.open()
|
|
ser.flushInput()
|
|
|
|
byte, data = 0, ""
|
|
|
|
def dump(d, prefix=''):
|
|
print(prefix + ' '.join(x.encode('hex') for x in d))
|
|
|
|
def construct_command(cmd, data=[]):
|
|
assert len(data) <= 12
|
|
data += [0,]*(12-len(data))
|
|
checksum = (sum(data)+cmd-2)%256
|
|
ret = "\xaa\xb4" + chr(cmd)
|
|
ret += ''.join(chr(x) for x in data)
|
|
ret += "\xff\xff" + chr(checksum) + "\xab"
|
|
|
|
if DEBUG:
|
|
dump(ret, '> ')
|
|
return ret
|
|
|
|
def process_data(d):
|
|
r = struct.unpack('<HHxxBB', d[2:])
|
|
pm25 = r[0]/10.0
|
|
pm10 = r[1]/10.0
|
|
checksum = sum(ord(v) for v in d[2:8])%256
|
|
return [pm25, pm10]
|
|
#print("PM 2.5: {} μg/m^3 PM 10: {} μg/m^3 CRC={}".format(pm25, pm10, "OK" if (checksum==r[2] and r[3]==0xab) else "NOK"))
|
|
|
|
def process_version(d):
|
|
r = struct.unpack('<BBBHBB', d[3:])
|
|
checksum = sum(ord(v) for v in d[2:8])%256
|
|
print("Y: {}, M: {}, D: {}, ID: {}, CRC={}".format(r[0], r[1], r[2], hex(r[3]), "OK" if (checksum==r[4] and r[5]==0xab) else "NOK"))
|
|
|
|
def read_response():
|
|
byte = 0
|
|
while byte != "\xaa":
|
|
byte = ser.read(size=1)
|
|
|
|
d = ser.read(size=9)
|
|
|
|
if DEBUG:
|
|
dump(d, '< ')
|
|
return byte + d
|
|
|
|
def cmd_set_mode(mode=MODE_QUERY):
|
|
ser.write(construct_command(CMD_MODE, [0x1, mode]))
|
|
read_response()
|
|
|
|
def cmd_query_data():
|
|
ser.write(construct_command(CMD_QUERY_DATA))
|
|
d = read_response()
|
|
values = []
|
|
if d[1] == "\xc0":
|
|
values = process_data(d)
|
|
return values
|
|
|
|
def cmd_set_sleep(sleep=1):
|
|
mode = 0 if sleep else 1
|
|
ser.write(construct_command(CMD_SLEEP, [0x1, mode]))
|
|
read_response()
|
|
|
|
def cmd_set_working_period(period):
|
|
ser.write(construct_command(CMD_WORKING_PERIOD, [0x1, period]))
|
|
read_response()
|
|
|
|
def cmd_firmware_ver():
|
|
ser.write(construct_command(CMD_FIRMWARE))
|
|
d = read_response()
|
|
process_version(d)
|
|
|
|
def cmd_set_id(id):
|
|
id_h = (id>>8) % 256
|
|
id_l = id % 256
|
|
ser.write(construct_command(CMD_DEVICE_ID, [0]*10+[id_l, id_h]))
|
|
read_response()
|
|
|
|
if __name__ == "__main__":
|
|
while True:
|
|
cmd_set_sleep(0)
|
|
cmd_set_mode(1);
|
|
for t in range(15):
|
|
values = cmd_query_data();
|
|
if values is not None:
|
|
print("PM2.5: ", values[0], ", PM10: ", values[1])
|
|
time.sleep(2)
|
|
|
|
# open stored data
|
|
with open('/var/www/html/aqi.json') as json_data:
|
|
data = json.load(json_data)
|
|
|
|
# check if length is more than 100 and delete first element
|
|
if len(data) > 100:
|
|
data.pop(0)
|
|
|
|
# append new values
|
|
data.append({'pm25': values[0], 'pm10': values[1], 'time': time.strftime("%d.%m.%Y %H:%M:%S")})
|
|
|
|
# save it
|
|
with open('/var/www/html/aqi.json', 'w') as outfile:
|
|
json.dump(data, outfile)
|
|
|
|
print("Going to sleep for 1 min...")
|
|
cmd_set_mode(0);
|
|
cmd_set_sleep()
|
|
time.sleep(60)
|