40 lines
2.3 KiB
Markdown
40 lines
2.3 KiB
Markdown
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Hello! I have written a v2 usermod for the BME280/BMP280 sensor based on the [existing v1 usermod](https://github.com/Aircoookie/WLED/blob/master/usermods/Wemos_D1_mini%2BWemos32_mini_shield/usermod_bme280.cpp). It is not just a refactor, there are many changes which I made to fit my use case, and I hope they will fit the use cases of others as well! Most notably, this usermod is *just* for the BME280 and does not control a display like in the v1 usermod designed for the WeMos shield.
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- Requires libraries `BME280@~3.0.0` (by [finitespace](https://github.com/finitespace/BME280)) and `Wire`. Please add these under `lib_deps` in your `platform.ini` (or `platform_override.ini`).
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- Data is published over MQTT so make sure you've enabled the MQTT sync interface.
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- This usermod also writes to serial (GPIO1 on ESP8266). Please make sure nothing else listening on the serial TX pin of your board will get confused by log messages!
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To enable, compile with `USERMOD_BME280` defined (i.e. `platformio_override.ini`)
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```ini
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build_flags =
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${common.build_flags_esp8266}
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-D USERMOD_BME280
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```
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or define `USERMOD_BME280` in `my_config.h`
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```c++
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#define USERMOD_BME280
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```
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Changes include:
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- Adjustable measure intervals
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- Temperature and pressure have separate intervals due to pressure not frequently changing at any constant altitude
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- Adjustment of number of decimal places in published sensor values
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- Separate adjustment for temperature, humidity and pressure values
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- Values are rounded to the specified number of decimal places
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- Pressure measured in units of hPa instead of Pa
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- Calculation of heat index (apparent temperature) and dew point
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- These, along with humidity measurements, are disabled if the sensor is a BMP280
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- 16x oversampling of sensor during measurement
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- Values are only published if they are different from the previous value
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- Values are published on startup (continually until the MQTT broker acknowledges a successful publication)
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Adjustments are made through preprocessor definitions at the start of the class definition.
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MQTT topics are as follows:
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Measurement type | MQTT topic
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--- | ---
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Temperature | `<deviceTopic>/temperature`
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Humidity | `<deviceTopic>/humidity`
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Pressure | `<deviceTopic>/pressure`
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Heat index | `<deviceTopic>/heat_index`
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Dew point | `<deviceTopic>/dew_point`
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