airQuality

This package adds functionality to the weather:bit board sold by SparkFun.

To use this package, go to https://makecode.microbit.org, click Add Package and search for: https://github.com/ADataDate/pxt-airQuality in the search bar.

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This package is still under development and subject to changes.

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Usage

• The CCS811 Air Quality Sensor can be directly mated to the matching pins (I2C) of the weather:bit for micro:bit system.
• I2C is set up so the user needs to start the device, then read the data.
• The CCS811 sensor takes 20 minutes to burn-in or get meaningful data.
• The TVOCs are presented as number between 0ppb to 1187ppb.
• The eCO2 (equivalent CO2) is presented as a number between 400ppm to 8192ppm.

Micro:bit Pins Used

• P19 -- I2C - SCL
• P20 -- I2C - SDA

CCS811 Start Function

The first block in the AirQuality package is the |CCS811 Start| block. At the start of any program which will use the air quality sensor place the |CCS811 Start| block in a "Forever" block above the rest of your code.

Air Quality Data

The CCS811 air quality sensors communicates via I2C. The data returned as a number can be stored in a variable, displayed on the 5x5 LED Matrix or sent serially to OpenLog.

• |CCS811 Start|block sets the CCS811 sensor into APP MODE - basically turns it on and ready to transmit data
• |Read eCO2|block reads the equivalent CO2 and can be any number between 400ppm and 8182ppm.
• |Read TVOCs|block reads the total organic volatile compounds and can be any number between 0ppb to 1187ppb.
• |Device Error|block is used while troubleshooting otherwise don't use it. It will return a number corresponding to a specific error on the CCS811.
• |Device Status|block is used while troubleshooting otherwise don't use it.
• |HWID|block is used to test the most basic read on the I2C line. Use if you are having probelms establishing communication.

Example Project:

The following project will read the eCO2 and TVOCs data and then display it on the 5x5 LED matrix.

let eCO2 = 0
let TVOCs = 0
basic.forever(() => {
    TVOCs = airQuality.readTvoc()
    eCO2 = airQuality.readCo2()
    basic.showString("TVOC")
    basic.showNumber(TVOCs)
    basic.pause(1000)
    basic.showString("eCO2")
    basic.showNumber(eCO2)
    basic.pause(1000)
})
airQuality.appStart()

License

MIT

Supported targets

• for PXT/microbit

airQuality=github:ADataDate/pxt-airQuality