A functional IAQ IoT Device

In the previous post, we prototyped a simple sensor shield in Eagle. There is still plenty of available space left on the PCB and sensors are cheap. Let’s add some more stuff and build a functional device. Adding Sensors We already have a CO2 sensor in the design. This can detect CO2 concentrations of 450 - 2000 ppm and TVOC (Total Volatile Organic Compounds) equivalents in the 125-600 ppb range. »