@ledbelly2142 said in Analog CO2 Sensor for LoPy, can 5v pin power it?: @bmarkus The COZIR sensors look nice. Are they in the sub $100 range? First hit of Google search gives $109 USD https://www.co2meter.com/products/cozir-0-2-co2-sensor As an indication you can visit the webshop of ChipCAD, a Hungarian distributor https://shop.chipcad.hu/Welcome/Default.aspx?scenarioID=360&pid=1878 Prices are in HUF (Hungarian Forint), VAT not included. At the moment 1 USD = 262.6 HUF But it may vary by distributor, quantity, shipping conditions, custom, etc. and model. You can ask GSS to advice where to buy it, they are good.