36 lines
2.8 KiB
Markdown
36 lines
2.8 KiB
Markdown
I was curious about how precise the "local" weather forecasts are and ended up ordering a cheap weather station "kit" from Ali Express so I could compare my measurements with the measurements that come from various "hyper local" weather forecast services.
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When deployed, it's supposed to look something like this:
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Each of the sensors plugs into a controller board that looks like this:
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Eventually, a box of sensors and a controller board arrived in the mail. There was no included documentation and what little additional documentation that I have found online since ordering and deploying the station has been collected and added to the [`docs`](./docs) folder. Small tweaks to the code included in this repo based on what i've learned from the documentation.
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Each of the sensors is quite simple, but w/o any documentation, it's impossible to know how much rain fall each pulse from the rain fall sensor equates to... etc.
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I didn't want to spend much time trying to reverse engineer the sensors or figure out how to drive them, so I spent most of my time trying to work *with* the bundled controller. I did get some decipherable documentation via google translate and, after a bit of trial and error, managed to get a PoC Arduino sketch that could decode the packets. After a bit more work, the Arduino code was ported over to the ESPHome platform. That's what's included here.
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C/C++ is not my preferred language, so the code "works" but could probably be optimized in quite a few ways. Pull Requests are accepted!
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## Adding support for Particulate Sensors
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A more detailed writeup and a basic 3d printable enclosure for outdoor deployments is written up [here](https://karlquinsland.com/2020/08/adding-an-airborne-particulate-mater-sensor-to-ws3-weather-station/).
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In short, the WS3 supports a specific [particulate matter sensor](https://rover.ebay.com/rover/1/711-53200-19255-0/1?mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2FDigital-Universal-Particle-Concentration-Laser-Sensor-PMS5003-PM1-0-PM2-5-PM10%2F254616699639&campid=5338734064&toolid=10001&customid=) (Note: Affiliate link; thanks for your support!). Making a cable to interface the sensor with the WS3 module isn't too much work and is discussed in the detailed writeup linked above.
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I've updated the `custom_component` for the WS3 station to support the sensor. Just set the `SUPPORT_PM25_SENSOR` to `1` and run `esphome your_file.yaml run --upload-port ...` to build and upload a new FW version.
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While hacking on the additional support, these existing repos were helpful in figuring out which values from the PM2.5 the WS3 was forwarding:
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- https://github.com/rpanfili/airQualityMeter
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- https://github.com/i3water/Blinker_PMSX003ST/blob/master/src/BLINKER_PMSX003ST.cpp
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The [datasheet](docs/PMS5003ST_Datasheet.pdf) has been included for reference.
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