I recently picked up an Arduino Uno starter kit and am looking forward to getting to play around with some musical applications.
Arduino is an open source embedded platform which is ideal for beginners and hobbyists as it is cheap and relatively easy to use hardware and software.
Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be stand-alone or they can communicate with software running on a computer (e.g. Flash, Processing, MaxMSP).
As it’s relatively lightweight, Arduino isn’t appropriate for most realtime musical processing or DSP programming (although it is possible), however as an interface or physical switch it is ideal (The Line 6 Tonecore DSP Development Kit looks like it may be a good candidate for more advanced realtime processing for making your own stompboxes). The microcontroller is the Atmel ATMega358 and is programmed using the Arduino Programming language, which is a variation of the C programming language – the most common programming language for embedded systems worldwide (I highly recommend “Programming Embedded Systems” by Michael Barr and Anthony Massa for a more in-depth introduction to embedded programming using C)
From the FAQ:
Can I program the Arduino board in C?
In fact, you already are; the Arduino language is merely a set of C/C++ functions that can be called from your code. Your sketch undergoes minor changes (e.g. automatic generation of function prototypes) and then is passed directly to a C/C++ compiler (avr-g++). All standard C and C++ constructs supported by avr-g++ should work in Arduino. For more details, see the page on the Arduino build process.
The Arduino Blog has some interesting applications and projects from the community. It can be browsed by category and the music tag has some nice projects featured, such as a Theremin, a Chess Sequencer, and – my favorite – “Moppy” – a musical floppy controller!