福申FS005甲醛传感器

fs005.py

# FS005009 Formaldehyde (HCHO) sensor
# 0       1         2     3         4             5               6            7       8
# 起始位  设备类型  单位  小数位数  气体浓度高位  气体浓度低位    满量程高位    满量程低位   校验值
# ff      17       04     00        00            1b              07          d0       f3
#
# 气体浓度值=气体浓度高位*256+气体浓度低位, 单位:mg/m3
# Sample output:
# ff 17 04 00 00 1b 07 d0 f3


import _thread as thread
import time
import serial
import json
import base64
import re


class FS005():
    def __init__(self, port='/dev/ttyUSB0'):
        self.port = port
        self.baudrate = 9600
        self.concentration = 0
        self.ser = None

    def start(self):
        self.ser = serial.Serial(
            # 这里设置串口端口
            port=self.port,
            baudrate=self.baudrate,
            parity=serial.PARITY_NONE,
            stopbits=serial.STOPBITS_ONE,
        )
        thread.start_new_thread(self.start_reader, ())


    def read(self):
        return self.concentration

    def start_reader(self):
        # wait for serial port
        while not self.ser.isOpen():
            print(f'Waiting device on port {self.port} ...')
            time.sleep(3)

        # clear previous data from serial port
        while self.ser.inWaiting() > 0:
            n = self.ser.inWaiting()
            self.ser.read(self.ser.inWaiting())
            time.sleep(0.1)

        # start reading loop
        while True:
            data = self.ser.read_all()
            if not data:
                time.sleep(1)
                continue
            if len(data) != 9:
                print(f'Invalid data len: {data}')
                continue

            if list(data[:4]) != [0xff, 0x17, 0x04, 0x00]:
                print(f'Invalid data: {data[:4]}')
                continue

            low = data[5]
            high = data[4]
            val = (high * 256 + low) / 1000.0
            self.concentration = val

if __name__ == '__main__':
    reader = FS005('/dev/ttyUSB0')
    reader.start()
    while True:
        print(f'val: {reader.read()}')
        time.sleep(2)