https://github.com/elixir-sensors/sgp40

Use Sensirion SGP40 air quality sensor in Elixir
https://github.com/elixir-sensors/sgp40

elixir iaq nerves-project sgp sgp4

Last synced: 4 months ago
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Use Sensirion SGP40 air quality sensor in Elixir

• Host: GitHub
• URL: https://github.com/elixir-sensors/sgp40
• Owner: elixir-sensors
• Created: 2021-05-25T22:52:32.000Z (about 5 years ago)
• Default Branch: main
• Last Pushed: 2025-03-11T23:16:13.000Z (over 1 year ago)
• Last Synced: 2026-01-14T07:33:38.442Z (5 months ago)
• Topics: elixir, iaq, nerves-project, sgp, sgp4
• Language: C
• Homepage: https://hex.pm/packages/sgp40
• Size: 85 KB
• Stars: 5
• Watchers: 2
• Forks: 3
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

          
# SGP40

[![Hex version](https://img.shields.io/hexpm/v/sgp40.svg "Hex version")](https://hex.pm/packages/sgp40)

[![API docs](https://img.shields.io/hexpm/v/sgp40.svg?label=docs "API docs")](https://hexdocs.pm/sgp40)

[![CI](https://github.com/elixir-sensors/sgp40/actions/workflows/ci.yml/badge.svg)](https://github.com/elixir-sensors/sgp40/actions/workflows/ci.yml)

[![REUSE status](https://api.reuse.software/badge/github.com/elixir-sensors/sgp40)](https://api.reuse.software/info/github.com/elixir-sensors/sgp40)

Use [Sensirion SGP40](https://www.sensirion.com/en/environmental-sensors/gas-sensors/sgp40/) air quality sensor in Elixir.

The raw signal from the SGP40 sensor is processed using [Sensirion's software algorithm](https://github.com/Sensirion/embedded-sgp/blob/00768191892b2cc0d839ebf95998fc4a85b660c4/sgp40_voc_index/sensirion_voc_algorithm.h) to give the [VOC Index](https://cdn.sparkfun.com/assets/e/9/3/f/e/GAS_AN_SGP40_VOC_Index_for_Experts_D1.pdf) that represents an air quality value on a scale from 0 to 500 where a lower value represents cleaner air.

## Usage

```elixir

iex> {:ok, sgp} = SGP40.start_link(bus_name: "i2c-1")

{:ok, #PID<0.1407.0>}

iex> SGP40.measure(sgp)

{:ok, %SGP40.Measurement{voc_index: 123, timestamp_ms: 885906}}

```

For better accuracy, you can provide the SGP40 sensor with relative ambient humidity and ambient temperature from an external humidity sensor periodically.

```elixir

iex> SGP40.update_rht(sgp, humidity_rh, temperature_c)

:ok

```

Depending on your hardware configuration, you may need to modify the call to

`SGP40.start_link/1`. See `t:SGP40.options/0` for parameters.