This document summarizes several hardware projects related to Arduino and concurrency. It discusses how Arduino is a great platform for education, hacking, and prototyping due to its open source nature, cross-platform support, and abundant resources. It then introduces three specific projects: the Concurrency Board developed by Omer Kilic, the Cardboarduino developed by Matt Jadud, and work connecting the Arduino to the occam-pi programming language done by Adam Sampson and others. Details are provided about each project and how they explore concurrency and distributed systems using Arduino.