This chapter was about interfacing I/O boards to ROS and adding sensors on it. We have discussed interfacing of the popular I/O board called Arduino to ROS, and interface basic components such as LEDs, buttons, accelerometers, ultrasonic sound sensors, and so on. After seeing the interfacing of Arduino, we discussed how to setup ROS on Raspberry Pi 2 and Odroid-C1. We also did few basic examples in Odroid and Raspberry Pi based on ROS and Wiring Pi. In the end, we saw the interfacing of smart actuators called Dynamixel in ROS.