arduino uno CO2, temperature and humidity sensor

Scheme

Components

• Display: MT-16S2H (16x2 pixels)
• Temperature & humidity: DHT22
• CO2: MH-Z19
• Resistor 10k Ohm

Features

Based on CO2 concentration there is LCD backlight control. When PPM >= 800 and PPM <= 1200 is starts to illuminate. When it's greater than 1200, LED starts to periodically blind.