The standard MarcDuino system uses two boards, a Master and a Slave (see the overview). The Master hooks up to the radio, 10 dome panel servos, the sound system and the Slave board. The Slave in turn hooks up to the Teeces dome lights, the holo lights, the holo servos, and the Magic Panel lights. Slave and Master are essentially the same boards (actually, exactly the same for v1.1 and v1.5), but the firmware that runs on it is different.
Most people use two boards, but you can have systems with more or less boards. If you just need the sound and/or the panels, you can have a minimum system with just the Master. The SHADOW+MarcDuino system uses 3 boards: a Master and a Slave in the dome, plus another Master in the body repurposed for the body panels.
MarcDuino v1, v2, and v1.5 (left to right)
There are now 3 generations of MarcDuino boards, folllow the links to get to their respective pages.
The MarcDuino v1 (v1.0 or v1.1 boards) is the original DIY board. The v1 is the base for all other versions, so most of the MarcDuino info is still found under here. It still works very well, and you can update it to run the v2 firmware with all the latest features. However, we recommend to use the better laid out v1.5 boards for new builds.
The MarcDuino v2 is the ultimate MarcDuino. It has cleanly marked labels, a piggy-back power supply, an integrated socket for the XBee radios, and add support to connect I2C gadgets. It uses surface mount components, so you can't make one yourself. I made only one large fab run of them, and they are now all sold out. I do not currently plan to make another run. Use the MarcDuino v1.5 instead, which is essentially a back port of the v2 in the v1-like design.
The MarcDuino v1.5 is the current and recommended MarcDuino. It is the most compact of the MarcDuinos. It combines the best of the v1 and the v2. It is also far easier to produce in small quantities, so you can order one pre-built from Astromech.net builder Mowee. So easy in fact that like the v1, you can even build it yourself. It inherits the all the goodies of the v2, except for the integrated power supply and XBee socket.