CO2 Signalizator device

A device for displaying CO2 in air (ppm), as well as an alarm when a certain level is exceeded.

Devices

- Arduino Uno (or etc arduino-compatible)
- MQ9 Sensor
- Active Buzzer
- 7-segment 4-digit display with two-74HC595D-chip (In diagram shows a model with a single 74HC595D chip. You will need to use a different display driver to work with it)