如何自己動手製作一個靠譜的PM2.5檢測儀

#main.py

import pyb

import upcd8544

from machine import SPI,Pin

from pyb import UART

from ubinascii import hexlify

from ubinascii import *

leds = [pyb.LED(i) for i in  range(1,5)]

P,L,SHUCHU=0,0,0

#A比例係數，在北方一般使用800-1000.南方空氣好一些，一般使用600-800.這個還和你使用的感測器靈敏度有關的，需要自己測試再定下來

A=800

#G為固定係數，是為了把串口收到的數據轉換成PM標準值

G=1024/5

SPI = pyb.SPI(1) #DIN=>X8-MOSI/CLK=>X6-SCK

#DIN =>SPI(1).MOSI "X8" data flow (Master out, Slave in)

#CLK =>SPI(1).SCK  "X6" SPI clock

RST    = pyb.Pin("Y10")

CE     = pyb.Pin("Y11")

DC     = pyb.Pin("Y9")

LIGHT  = pyb.Pin("Y12")

lcd_5110 = upcd8544.PCD8544(SPI, RST, CE, DC, LIGHT)

u2 = UART(2, 2400)

count_=0

def ChangeLEDState(num_):

   global leds

   len_=len(leds)

   for i in range( 0,len_):

       if i!=num_:

           leds[i].off()

       else:

           leds[i].on()

while True:

   u2.init(2400, bits=8 , parity=None, stop=1)

   pyb.delay(80)

   Quality="DATA NULL"

   if(u2.any()>0 ):

       u2.deinit()

       _dataRead=u2.readall()

       #R代表截取數據的起始位

       R=_dataRead.find(b"xaa" )

       #R>-1代表存在起始位，長度大於起始位位置+2

       if R>-1  and len(_dataRead)>(R+2):

           P=_dataRead[R+ 1]

           L=_dataRead[R+ 2]

           #把串口收到的十六進位數據轉換成十進位

           SHI=P* 256+L  

           SHUCHU=SHI/ G*A

       if(SHUCHU<35):

           Quality = "Excellente"

           print("環境質量:優", "PM2.5=",SHUCHU)

           count_=1

       elif(35<SHUCHU< 75):

           Quality = "Good"

           print("環境質量：良好", "PM2.5=",SHUCHU)

           count_=1

       elif(75<SHUCHU< 115):

           Quality = "Slightly-polluted"

           print("環境質量：輕度污染 ", "PM2.5=",SHUCHU)

           count_=3

       elif(115<SHUCHU< 150):

           Quality = "Medium pollution"

           print("環境質量：中度污染 ", "PM2.5=",SHUCHU)

           count_=2

       elif(150<SHUCHU< 250):

           Quality = "Heavy pollution"

           print("環境質量：重度污染 ", "PM2.5=",SHUCHU)

           count_=0

       elif(250<SHUCHU):

           Quality = "Serious pollution"

           print("環境質量：嚴重污染 ", "PM2.5=",SHUCHU)

           count_=0

   ChangeLEDState(count_)

   lcd_5110.lcd_write_string("AQI Level",0, 0)

   lcd_5110.lcd_write_string(str(Quality),0, 1)

   lcd_5110.lcd_write_string("PM2.5:",0, 2)