Zorac wrote:thanks. i was coming to a similar conclusion at looking at some sample code. I was hoping to get a ppm readout, but i may still give this a try as there doesn't appear to be any other options.
Hi everyone, this is my first post
I've been working on a project using a Raspberry Pi B+ with an MQ135 sensor and an MCP3008 ADC. Everything is connected and working but I have no idea about what does the readout from the sensor mean. Normally I get some value between 25 - 50 in clean air.
After doing some research I found a similar project that uses a tp-401 sensor which is also for air quality measurement and they use the following table to interpret their data.
Now my idea is the following: since we know that the MQ135 returns a value between 0 and 1023 why not using cross multiplication to convert the numbers, so 1023 would be equal to 500 and then we can use the AQI table to interpret the sensor readout.
Any comments regarding this are welcome
(sorry my english is a bit rusty)