Calibration Tool for the SCD-30 CO₂ sensors with the I2C interface such as those sold by Adafruit. Intended for use when calibrating multiple sensors for the DIY Frugal Arduino CO2 Sensor

Instructions are a work in-progress.

1. Assemble the DIY Frugal Arduino CO2 Sensor
2. Add 3x push buttons and resistors (anything 1kΩ - 100kΩ is fine) to each of ports A0, A1, and A2. See the official Arduino instructions for push button circuits
3. Load the SCD-30_CO2_Calibrator_Tool.ino code using Arduino IDE.
4. The device defaults to a target setting of 420ppm, a typical outdoor ambient concentration. If you need a different value, press the button connected to A1 to increase the value & button on A2 to decrease it in increments of 10ppm. Note the button re-checks approximately once per second, so you will need to long-press and hold until the value changes.
5. When the target "SetTo:" value is correct, push the button on A0 once to run the calibration. The screen will display "Calibrated!" for a few seconds. It will continue to display CO₂ readings under the "CO2:" heading; leave it running for at least 30 seconds to verify it was set correctly (it may not have set correctly if the CO₂ concentration varied at the moment the button was pressed).
6. To calibrate additional sensors, simply swap the sensor port to a new sensor. The machine may automatically restart; that is okay.

Eric Woo-Shem: Design of original sensor, Arduino & circuit debugging, review & editing.

Brian Woo-Shem: Design & programming for calibration tool, documentation, testing and validation.

All text, graphics, and non-code content is licensed CC BY-NC-SA
All code is licensed under the GNU General Public License v3

RTClib and Adafruit_SCD30 are Copyright (c) Adafruit Industries and used under the open source MIT license.
Arduino IDE and related components are open source and licensed under the GNU GPL v2 and/or CC BY-SA Arduino.