Open Sound Control (OSC) is a communications protocol that can be seen as a modern alternative to MIDI. It’s specifically designed to play nicely with network communication systems. The problem with using it along with Arduino-based gadgets is that you then need to use something like an Ethernet shield to provide the network connection. [Liam Lacey] decided to use Processing as a go-between for OSC and the Arduino in lieu of the Ethernet Shield. One of the major benefits of this method is that it gives you some flexibility when it comes to how the Arduino communicates. Since a USB connected Arduino can be addressed by the Processing sketch in the same way as an AVR chip connected via an RS232 serial port, [Liam’s] method will allow you to prototype on an Arduino board, but transition to your own non-USB hardware for the finished project. The one big drawback to this method is the need to have a computer connected to your controller, but we’d bet you’d need one to run MAXmsp anyway.