SDS011/pythoncode.py at master · FriskByBergen/SDS011 · GitHub

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"""
    program to read data from Novafitness SDS101
    http://aqicn.org/sensor/sds011/

    Nils Jacob Berland
    njberland@gmail.com / njberland@sensar.io
    +47 40800410

    The numbers produced are microgram pr m^3 of particles
"""
import serial

# check for the existence of /dev/tty**** !!!
# drivers may be based on the CH34x USB SERIAL CHIP:
# https://tzapu.com/making-ch340-ch341-serial-adapters-work-under-el-capitan-os-x/
# http://www.microcontrols.org/arduino-uno-clone-ch340-ch341-chipset-usb-drivers/
#
ser = serial.Serial('/dev/tty.wchusbserial1410', baudrate=9600, stopbits=1, parity="N",  timeout=2)

#
while True:
    s = ser.read(1)
    if ord(s) == int("AA",16):
        s = ser.read(1)
        if ord(s) == int("C0",16):
            s = ser.read(7)
            a = []
            for i in s:
                a.append(i)
            #print(a)
            pm2hb= s[0]
            pm2lb= s[1]
            pm10hb= s[2]
            pm10lb= s[3]
            cs = s[6]
            # we should verify the checksum... it is the sum of bytes 1-6 truncated...

            try:
                print("PM2.5 - ", float(pm2hb + pm2lb*256)/10.0 ," PM10 - ", float(pm10hb + pm10lb*256)/10.0)
            except:
                pass
    else:
        pass