A 1-Wire controller with two open-drain GPIO from Adafruit.
You can put as many of the DS2413's as you want on a single I/O line, each one is uniquely addressable and shares the single I/O pin happily. The two controllable I/O lines (PIOA and PIOB) can be used as inputs or outputs. They are open-drain, so if you want to power an LED or something, you'll need a remote power supply. Don't forget to add the 4.7Kohm resistor from I/O to your 1-Wire controller power supply (3.3V - 5V) on the Arduino side of the wires.
- Dimensions: 15.78mm / 0.62" x 9.96mm / 0.39" x 2.94mm / 0.11"