Over the past three months, we’ve been working hard to finalize the specs for the Raspberry Pi (ultra-low-cost computer, for use in teaching computer programming to children) device, and to produce schematics and a PCB layout. Last Tuesday, we sent an alpha release of the board for manufacture. From an electrical perspective, this board is intended to be identical to the final device; the resulting units will be used to validate the schematic design, and will serve as our interim software development platform.

Key differences between the alpha and final boards are:

• The alpha board is roughly 20% larger than the credit-card-sized final board. As you can see, our size is already dominated by the area of the various connectors.
• The alpha board has six layers rather than four, and uses a variety of expensive HDI features (blind and buried vias, via-in-pad) which we wish to eliminate from the final board.
• The alpha board has various test and debug features which will not be present on the final board.

Following the example of the BBC Micro, we intend to launch both a Model A device (lacking the LAN9512, and with 128MB of RAM) at the $25 price point, and a Model B device (including the LAN9512, and with 256MB of RAM) for a $5-10 additional cost. We remain confident of shipping before the end of 2011.

Check back in a couple of weeks to see how the alpha boards turned out.

www.raspberrypi.org