1-wire/iButtons - 1-Wire is a communication bus designed by Dallas Semiconductor that allows communication and power to connected devices over a single data wire. 1-Wire is similar to I²C, but has a lower data rate and can communicate over longer distances. 1-Wire is commonly used to communicate with small and inexpensive devices such as temperature sensors and digital I/O devices. A network of 1-Wire devices and a corresponding 1-Wire master is called a MicroLan. A distinctive feature of 1-Wire is that only two wires are required for basic functions: data and ground. To make this work, most 1-Wire devices have a built-in capacitor that “steals” power from the data wire. Each 1-Wire chip has a unique ID number.