read and log data from dust sensor PM2.5 Plantower PMS7003

readPMS7003.py

#! /usr/bin/python2
"""
Binh Nguyen, Deccember 01, 2018
forked from Mark Benson's gist
Read a Plantower PMS7003 serial sensor data.
English datasheet: https://www.pdf-archive.com/2017/04/12/plantower-pms-7003-sensor-data-sheet/plantower-pms-7003-sensor-data-sheet.pdf
The sensor payload is 32 bytes:
"""

import serial
import time
import os

physicalPort = '/dev/ttyUSB0'
serialPort = serial.Serial(physicalPort)  # open serial port
logFile = 'PMS7003_header.csv'
debug = False
keep_going = True
lastTime = 0
intervalSampling = 59 # seconds

headers = 'time,pm1.0_ac,pm2.5_ac,pm10_ac,pm1.0_cf,pm2.5_cf,pm10_cf\n'
with open(logFile, 'a+') as f:
    head_ = f.readline().lower()
    if not head_.startswith("data captured"):
        f.write('Data captured Python Script directly from PMS7003 >> USB >>PC\n')
        f.write(headers)
        print('add header')
    else:
        time_ = time.strftime('%x %X', time.localtime())
        sprtor = '{},None,None,None,None,None,None\n'.format(time_)
        f.write(sprtor)

def log_data(logFile, msg):
    with open(logFile, 'a') as f:
        timestamp = time.strftime('%x %X', time.localtime())
        try:
            print('Type of MSG {}'.format(type(msg)))
            assert type(msg) == str
            msg = ','.join((timestamp, msg))
            f.write(msg)
            print('Log data successfully')
            return None
        except Exception as e:
            print('Error! {}'.format(e))
            return -1

def read_pms7003(debug=False):
	# important !!! reset buffer for interval reading to clear up old data
    serialPort.reset_input_buffer()
    time.sleep(0.7) # wait for new data to populate
    if serialPort.in_waiting >= 32:
        # Check that we are reading the payload from the correct place (i.e. the start bits)
        while not (ord(serialPort.read()) == 0x42 and ord(serialPort.read()) == 0x4d):
            time.sleep(0.7)
            print('waiting for the head')

        # Read the remaining payload data
        data = serialPort.read(30)
        # Extract the byte data by summing the bit shifted high byte with the low byte
        # Use ordinals in python to get the byte value rather than the char value
        frameLength = ord(data[1]) + (ord(data[0])<<8)
        # Standard particulate values in ug/m3
        concPM1_0_CF1 = ord(data[3]) + (ord(data[2])<<8)
        concPM2_5_CF1 = ord(data[5]) + (ord(data[4])<<8)
        concPM10_0_CF1 = ord(data[7]) + (ord(data[6])<<8)
        # Atmospheric particulate values in ug/m3
        concPM1_0_ATM = ord(data[9]) + (ord(data[8])<<8)
        concPM2_5_ATM = ord(data[11]) + (ord(data[10])<<8)
        concPM10_0_ATM = ord(data[13]) + (ord(data[12])<<8)
        # Raw counts per 0.1l
        rawGt0_3um = ord(data[15]) + (ord(data[14])<<8)
        rawGt0_5um = ord(data[17]) + (ord(data[16])<<8)
        rawGt1_0um = ord(data[19]) + (ord(data[18])<<8)
        rawGt2_5um = ord(data[21]) + (ord(data[20])<<8)
        rawGt5_0um = ord(data[23]) + (ord(data[22])<<8)
        rawGt10_0um = ord(data[25]) + (ord(data[24])<<8)
        # Misc data
        version = ord(data[26])
        errorCode = ord(data[27])
        payloadChecksum = ord(data[29]) + (ord(data[28])<<8)

        # Calculate the payload checksum (not including the payload checksum bytes)
        inputChecksum = 0x42 + 0x4d
        for x in range(0,27):
                inputChecksum = inputChecksum + ord(data[x])

        # os.system('clear') # Set to 'cls' on Windows
        # print("PMS7003 Sensor Data:")
        # print("PM1.0 = " + str(concPM1_0_CF1) + " ug/m3")
        # print("PM2.5 = " + str(concPM2_5_CF1) + " ug/m3")
        # print("PM10 = " + str(concPM10_0_CF1) + " ug/m3")
        # print("PM1 Atmospheric concentration = " + str(concPM1_0_ATM) + " ug/m3")
        print("PM2.5 AC= " + str(concPM2_5_ATM) + " ug/m3")
        # print("PM10 Atmospheric concentration = " + str(concPM10_0_ATM) + " ug/m3")
        # print("Count: 0.3um = " + str(rawGt0_3um) + " per 0.1l")
        # print("Count: 0.5um = " + str(rawGt0_5um) + " per 0.1l")
        # print("Count: 1.0um = " + str(rawGt1_0um) + " per 0.1l")
        # print("Count: 2.5um = " + str(rawGt2_5um) + " per 0.1l")
        # print("Count: 5.0um = " + str(rawGt5_0um) + " per 0.1l")
        # print("Count: 10um = " + str(rawGt10_0um) + " per 0.1l")
        # print("Version = " + str(version))
        # print("Error Code = " + str(errorCode))
        # print("Frame length = " + str(frameLength))
        if inputChecksum != payloadChecksum:
            print("Warning! Checksums don't match!")
            print("Calculated Checksum = " + str(inputChecksum))
            print("Payload checksum = " + str(payloadChecksum))
        log = ','.join([str(concPM1_0_ATM), str(concPM2_5_ATM),str(concPM10_0_CF1),\
                        str(concPM1_0_CF1), str(concPM2_5_CF1), str(concPM10_0_CF1)])+'\n'
        print('Returned log {}'.format(log))
        return str(log)


while keep_going:
    if time.time() - lastTime > intervalSampling:
        msg = read_pms7003()
        status = log_data(logFile, msg)
        print('Status {}'.format(status))
        if status == None:
            lastTime = time.time()
        else:
            time.sleep(0.1)