 iSquared C is a method for connecting devices and sensors to a microcontroller board or computer. It only has four pins, power, ground, clock, and data. There are iSquared C motion sensors, thermometers, air quality sensors, OLEDs, GPS modules, a wide range of devices. But iSquared C's special feature is its ability to connect multiple devices simultaneously. Stem a QT board like these can easily chain together multiple devices with a cable. Just keep in mind that each device in an iSquared C chain needs to have its own unique address. And devices with addresses that can't be changed can only be used once in a chain. If a board does have a fixed address, you'll usually see it printed on the back of the PCB. And if its address can be changed, you'll usually see a jumper or pin that'll let you do it.