Adafruit SCD-40 - True CO2, Temperature and Humidity Sensor

This sensor can run from 3.3 to 5V but it's more important for it to have a quiet power supply with low ripple, than any particular voltage. For that reason, Adafruit has added a 3.3V regulator and level shifters: when connecting to a 5V microcontroller like an Arduino UNO the 5V supply is often shared with other electronic components that add noise. The onboard regulator will keep the voltage nice and quiet.

Technical Detail

SCD-40 Specifications:
Photoacoustic CO2 sensor technology
Integrated temperature and humidity sensor
Measurement range: 400 ppm – 2000 ppm
Accuracy: ±(50 ppm + 5 % of reading)
Current consumption: 17 mA (meas. rate = 5 s) / 0.5 mA (meas. rate = 5 min)
Fully calibrated and linearized
I2C digital interface address 0x61
Sensor Element Size: 10.1mm x 10.1mm x 6.5 mm
Product Weight: 2.8g / 0.1oz
Product Dimensions: 25.5mm x 22.8mm x 7.7mm / 1.0" x 0.9" x 0.3"