https://github.com/pastcompute/simplepiaqsensor

https://github.com/pastcompute/simplepiaqsensor

Last synced: 16 days ago
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• Host: GitHub
• URL: https://github.com/pastcompute/simplepiaqsensor
• Owner: pastcompute
• License: gpl-2.0
• Created: 2021-05-17T12:27:14.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2021-05-30T13:52:00.000Z (over 3 years ago)
• Last Synced: 2024-10-03T12:23:45.506Z (about 1 month ago)
• Language: Python
• Size: 310 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Raspberry Pi CO2 sensor

This project provides a wrapper around [ReadSGP30](https://github.com/LuckyResistor/ReadSGP30) on any Raspberry Pi (will work on an Pi or Pi Zero, including the original Pi A/B), displaying the sensor value on an OLED display and also publishing the data on MQTT.

Tested using an original Pi B 512MB and Raspbian 10.

## Installation and Use

This assumes a fresh install of Raspbian 10 and the pi will be dedicated to this application.

- prepare a Raspberry Pi. It works on even an original Pi A or B with a USB Wifi adaptor, although it will be slow to install and debug.

- most recently I am running this on a new Pi 3B

- after booting a fresh SD card, run `sudo raspi-config`

  - setup your Wifi

  - I also run in console only mode

  - ensure you enable i2c, and enabling SSH is very helpful when debugging

- checkout this repository in /home/pi

- connect the SGP30 and SSD1306 to the Pi i2c bus

- install the [prerequisites](./prereq.sh)

- enable & start the systemd service

- the first time let the device run outside if possible for 12-24 hours to gain an accurate baseline

- as required, test the MQTT connection using `mosquitto_sub -t 'aqsensor/#'`

- this configuration by default is insecure, use at your own risk

## Customisation

- use the environment variable `MQTT_TOPIC`, this defaults to `aqsensor` and is appended with `/` and the serial number of the sensor

- send direct to an extenal MQTT server using `MQTT_HOST`; at the moment it uses the default port with `mosquitto_pub` 

- environment variables are set in the file `AQSensor.service`

## Maintenance

- the baseline info is saved in `/home/pi/.lr_read_sgp30/baseline.txt`

- to force it to be reset on next reboot run `touch /home/pi/AQSensor/reset-baseline.flag` (or just delete the directory)

- to send to an alterantive MQTT service (default is localhost) set the environment variable `MQTT_HOST` in the service file

## Todo

- document the pin connections, etc.