MCU680 Module for NodeMCU

Since	Origin / Contributor	Maintainer	Source
2019-03-01	Jan Simsa	Jan Simsa	mcu680.lua

This Lua code for NodeMCU provides access to module GY-MCU680V1 with sensor BME680 and MCU STM32 obtain temperature, humidity, atmospheric pressure, IAQ (indoor air quality) and resistance value. Data read is through serial port.

!!! note The module requires softuart, struct and bit C module built into firmware.

Require

mcu680 = require("mcu680")

Release

mcu680 = nil
package.loaded["mcu680"] = nil

mcu680:init()

Initializes UART port.

Syntax

mcu680.init(tx, rx)

Parameters

• tx UART Tx pin number.
• rx UART Rx pin number.

Returns

nil

mcu680:read()

Reads values from the module. Module send output every 3 seconds, the callback is executed once after first message received.

Syntax

mcu680:read(callback)

Parameters

• callback function that receives all results when all conversions finish

Callback function parameters

• temperature temperature in Celsius multiplied by 100
• humidity relative humidity in percent multiplied by 100
• pressure air pressure in hectopascals multiplied by 100
• iaq_accuracy The accuracy status is equal to zero during the power-on stabilization times of the sensor and is equal to 3 when the sensor achieves best performance
• iaq indoor air quality index
• gas_resistance gas resistance in Ohms
• altitude

Indoor air quality (IAQ) classification is described in BME680 datasheet on page 9, Table 4

IAQ Index	Air Quality
0 – 50	good
51 – 100	average
101 – 150	little bad
151 – 200	bad
201 – 300	worse
301 – 500	very bad

Returns

nil

Example

mcu680 = require("mcu680")
tx, rx = 1, 2
mcu680:init(tx, rx)
mcu680:read(function(temperature, humidity, pressure, iaq_accuracy, iaq, gas_resistance, altitude)
    print(string.format("Temperature: %g C", temperature/100))
    print(string.format("Humidity: %g %%", humidity/100))
    print(string.format("Pressure: %g hPa", pressure/100))
    print(string.format("IAQ accuracy: %g", iaq_accuracy))
    print(string.format("IAQ: %g", iaq))
    print(string.format("Gas resistance: %g Ohm", gas_resistance))
    print(string.format("Altitude: %g m", altitude))
end)