CO2 train sign

CO2 monitoring, displaying on the train signs.

For more information about the train signs, see https://github.com/sheffieldhackspace/train-signs

Environment monitor

The monitor is an SCD40: https://sensirion.com/products/catalog/SCD40

It has an accuracy of:

• CO2 accuracy: ±50.0 ppm
• temperature accuracy: 0.8 °C
• relative humidity accuracy: 6 %RH

Note that the sensor is within the sign enclosure, so the measurements are probably not very accurate, as there is likely not much airflow into the enclosure.

Project layout

This project consists of two folders:

• ./controller/ which is for the Arduino which controls the sign (basically the same as https://github.com/alifeee/openbenches-train-sign/tree/main/controller). It listens to Serial on an RX pin, and displays any text it receives (terminated by a null character "\0") on the sign.
• ./monitor/ which is a combination of https://github.com/alifeee/co2-monitoring and https://github.com/alifeee/openbenches-train-sign/tree/main/fetcher. It talks to the attached CO2 monitor and then sends the results to serial (to the Arduino Uno).

Development

1. install https://platformio.org/
2. cd into the relevant folder
3. run the relevant command below (or use the VSCode GUI extension)

build

pio run

upload

pio run -t upload

monitor

pio device monitor

wiring