hazeconf.json

{"ssid":"eatme", "password":"blergh", "apikey":"WhatKey?Monkey!", "device_id":"SniffSniff"}

pm25_data_hack.py

from m5stack import *
from m5ui import *
from machine import UART
import time
import struct
import network
import urequests
import ujson

# load config
f = open("/flash/hazeconf.json")
config = ujson.loads(f.read())

# setup wifi
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(config["ssid"],config["password"])

while not wlan.isconnected():
    lcd.print("connecting", 20, 20)
    lcd.clear()

if wlan.isconnected():
    # This is the only UART that works. 
    uart2 = UART(1, tx=17, rx=16)
    uart2.init(9600)
    while True:
        # Making data display more reasonable
        time.sleep_ms(750)
        lcd.clear()
        # The command to start measurement
        # source https://sensing.honeywell.com/honeywell-sensing-hpm-series-particle-sensors-datasheet-32322550-e-en.pdf
        # Page 5
        uart2.write('\x68\x01\x01\x96')
        data=uart2.read(32)
        # Opps there is problem, 
        # call the command to stop measurement every time there is problem
        if not data:
            lcd.print("No data", 20, 20)
            uart2.write('\x68\x01\x02\x95')
            continue
        # Should only have 32 bit of data
        if len(data) != 32:
            lcd.print("Bad data", 20, 20)
            lcd.print(data, 20, 30)
            uart2.write('\x68\x01\x02\x95')
            continue
        # measurement must start with 0x42
        if data[0] != 0x42:
            lcd.print("Bad data", 20, 20)
            lcd.print(data, 20, 30)
            uart2.write('\x68\x01\x02\x95')
            continue
        l = list(data)
        # The number is big endian. Also drop the first 4 byte
        # Covert the rest into 14 number
        frame = struct.unpack(">HHHHHHHHHHHHHH", bytes(l[4:]))
        # I really only care about frame[1] and frame[2]. WHich is PM2.5 and PM10
        # Source https://sensing.honeywell.com/honeywell-sensing-hpm-series-particle-sensors-datasheet-32322550-e-en.pdf
        # Page 6
        pm25=frame[1]
        pm100=frame[2]
        #output = "PM 2.5 = {pm25}".format(pm25=pm25)
        lcd.print(pm25, 20, 30)
        lcd.print(pm100, 20, 40)
        lcd.print("posting", 20, 50)
        try:
            headers = {"apikey":config["apikey"]}
            data = {
                "device_developer_id":config["device_id"],
                "data": {"pm2.5": pm25, "pm10":pm100}
            }
            r = urequests.post("https://api.favoriot.com/v1/streams", headers=headers, json=data)
            lcd.print("posted", 20, 60)
            lcd.print(r.status_code, 20, 70)
            result = r.json()
            lcd.print(result["status"], 20, 80)
            # be nice send data every 10 minute
            time.sleep(1000)

        except Exception as e:
            lcd.print(str(e), 20, 60)
        uart2.write('\x68\x01\x02\x95')