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https://github.com/paulgreg/co2-sensor
An esp8266 based CO2 sensor
https://github.com/paulgreg/co2-sensor
co2 esp8266 iot iot-device temperature
Last synced: 1 day ago
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An esp8266 based CO2 sensor
- Host: GitHub
- URL: https://github.com/paulgreg/co2-sensor
- Owner: paulgreg
- License: gpl-3.0
- Created: 2020-10-29T18:47:23.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2024-07-13T10:16:02.000Z (4 months ago)
- Last Synced: 2024-07-13T11:29:38.873Z (4 months ago)
- Topics: co2, esp8266, iot, iot-device, temperature
- Language: C
- Homepage: https://hackaday.io/project/175627-co2-temperature-sensors
- Size: 192 KB
- Stars: 8
- Watchers: 4
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# esp8266 CO2 sensor
That project goal is to mesure CO2 and if too high, tell user to open their windows.
It’s a simple way to remind to recycle air and so, reduce risk against COVID-19 in crowded space (like classrooms).
Inspiration is from [Eole project](http://lafabrique.centralesupelec.fr/projetco2/). Thanks
Optionaly, you can send data to a server (influxdb & grafana) to get values over time.
## Components
* esp8266 (I’ve used a Wemos D1 for tryout, and then an ESP8266 for definitive project)
* I2C 128X64 OLED LCD screen
* Humidity & temperature DHT11 sensor (needed as input to SGP30)
* SGP30 Air Quality Sensor CO2 sensor
## Connections
### I2C screen
* GND on GND
* VCC on 3.3V
* SCL on esp8266 D1
* SDA on esp8266 D2
### SGP30 sensor
* GND on GND
* VCC on 3.3V
* SCL on esp8266 D1
* SDA on esp8266 D2
### DHT11 sensor
* GND on GND
* VCC on 3.3V
* sensor to d5 / GPIO14
## Information
First copy `parameters.h.dist` to `parameters.h`.
It contains the `CO2_THRESHOLD` value which inverts the display.
It’s a simple way to bring attention to users to open windows.
As explained on [Adafruit SGP30 sensor page](https://learn.adafruit.com/adafruit-sgp30-gas-tvoc-eco2-mox-sensor/arduino-code), the SPG30 sensor needs to be calibrated with a baseline value (given by the sensor).
That baseline is periodically asked from SPG30 sensor and stored into EEPROM (~1 time per hour).
When the system boots, it's read from EEPROM and the SPG30 is calibrated with that value. That increase the sensor precision.
If I understood correctly, the best baseline value is get after 12 continuous hours of operation. If you don’t use the sensor for 7 days, you’ll have to let it run again for 12 hours to « reset » the correct baseline.
Also, the DHT11 sensor is used to compute absolute humidity level, also used to increase SGP30 precision.
If you define a `WIFI_SSID`, a `WIFI_PASSWORD` and a `INFLUXDB_URL` in `parameters.h`, the esp8266 will periodically send temperature, humidity & co2 to an influxdb database. You can set the location name (like the room where the sensor is placed) in `LOCATION` parameter.
## Grafana, Influxdb
You can install influxdb, telegraf (used for system metrics) & grafana via docker (links in reference).
You’ll have to create a `sensor` datbase via : `curl -XPOST -s http://localhost:8086/query\?pretty\=true --data-urlencode "q=CREATE DATABASE sensor"`
You can then send a test data :
`curl -i -XPOST 'http://localhost:8086/write?db=sensor' --data-binary 'temperature,location=home value=20.0'`
And read it back :
`curl -XPOST -s http://localhost:8086/query\?pretty\=true --data-urlencode "db=sensor" --data-urlencode "q=SELECT * FROM temperature"`
The grafana board I configured has been exported to grafana directory.
Here’s a sample output :
## References
### Hardware
* [Eole project](http://lafabrique.centralesupelec.fr/projetco2/)
* [I2C OLED screen](https://randomnerdtutorials.com/esp8266-0-96-inch-oled-display-with-arduino-ide/)
* [DHT11 sensor tryout](https://hackaday.io/project/175689/log/185783-humidity-temperature-module)
* [Adafruit SGP30 sensor explanation](https://learn.adafruit.com/adafruit-sgp30-gas-tvoc-eco2-mox-sensor/arduino-code)
* [esp8266 pinout reference](https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/)
* [Passage de la requête POST via ESP8266 à InfluxDB](https://stackoverrun.com/fr/q/10514644)
### Server
* [get system metrics for 5 min with docker telegraf influxdb and grafana](https://towardsdatascience.com/get-system-metrics-for-5-min-with-docker-telegraf-influxdb-and-grafana-97cfd957f0ac)
* [install grafana influxdb telegraf using docker compose](https://dev.to/project42/install-grafana-influxdb-telegraf-using-docker-compose-56e9)
* [Write data with the InfluxDB API](https://docs.influxdata.com/influxdb/v1.8/guides/write_data/)