I have a cheap jq-200 air quality sensor that measures CO2 amongst other things. You can get them on Ebay or Aliexpress for around $20. It connects to a WIFI network and then sends data to a server in China. There is also an iPhone/Android App that allows you to monitor the device.

I was able to pair it with the phone App and it works as advertised.

I used TCPDUMP to capture the data going between it and the server in China, it seems to be using MQTT to send a data string.

This string should contain, Temp, Humidity, CO2, HCHO and TVOC

The data string as ASCI is:


Does anyone see an obvious pattern that I am missing that would allow me to pull the data directly from the packet?

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