https://github.com/agners/micropython-scd30

MicroPython I2C driver for SCD30 CO2 sensor module
https://github.com/agners/micropython-scd30

Last synced: 2 months ago
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MicroPython I2C driver for SCD30 CO2 sensor module

• Host: GitHub
• URL: https://github.com/agners/micropython-scd30
• Owner: agners
• License: mit
• Created: 2019-07-12T22:32:28.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2023-02-27T07:00:55.000Z (over 1 year ago)
• Last Synced: 2024-03-28T03:22:43.433Z (3 months ago)
• Language: Python
• Size: 6.84 KB
• Stars: 23
• Watchers: 2
• Forks: 15
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Lists

• awesome-micropython - micropython-scd30 - MicroPython I2C driver for Sensirion SCD30 CO2 sensor module. (Libraries / Sensors)

README

        
# Sensirion SCD30 CO² Sensor I2C driver for MicroPython

Sensirion SCD30 is a CO², Humidity and Temperature sensor on a module. This is

a I2C driver written in Python 3 for MicroPython.

## Getting Started

### Prerequisites

* Sensirion SCD30 Sensor Module

* MicroPython board with I2C interface

### Wiring

Wire the I2C bus to the I2C bus on your MicroPython board. This is an example

using the Pyboard D:

| Pyboard       | SCD30         |

| ------------- |---------------|

| X15 (3V3)     | VDD           |

| X14 (GND)     | GND           |

| X9            | TX/SCL        |

| X10           | RX/SDA        |

### Usage

This example reads the measurements in a continous loop:

```

import time

from machine import I2C, Pin

from scd30 import SCD30

i2cbus = I2C(1)

scd30 = SCD30(i2c, 0x61)

while True:

    # Wait for sensor data to be ready to read (by default every 2 seconds)

    while scd30.get_status_ready() != 1:

        time.sleep_ms(200)

    scd30.read_measurement()

```

Note that the CO² sensor needs some time to stabilize. Therefor the sensor

should be kept powered to achieve a reasonable measurement interval (e.g. <5

minutes). To save power the sensors measurement inverval can be tweaked. See

also the [Low Power Mode for SCD30](https://docs-emea.rs-online.com/webdocs/16c9/0900766b816c9dc7.pdf)

application note.

### Calibration

The CO² sensor has two modes of calibration: FRC (Forced Recalibration) or ASC

(Automatic Self-Calibration). This only describes the former.

Essentially the sensor is already calibrated at factory. However, when setting a

new measurement interval recalibration might be necessary. The process is to

bring the sensor into a controlled environment (e.g. outside) and set the known

value at that environment (e.g. 400ppm). From what I understand ASC does

essentially the same, just assumes that the lowest values over a certain periode

are "outside values"...

Also note that the temperature sensor suffers from heating effects on the PCB.

When the sensor operates in 2 second interval the heating is about 3°C. I

usually run the sensor at 30 seconds interval and observed a heating of 2°C. The

offset is subtracted from the measured temperature! To set a new offset, take

the old offset into account!

## Built With

* [MicroPython](http://micropython.org/)

* [SCD30 Sensor Module](https://www.sensirion.com/en/environmental-sensors/carbon-dioxide-sensors-co2/)

## License

This project is licensed under the MIT License - see the

[LICENSE](LICENSE) file for details