by Dermot Tynan in Microtransat

Posted on Saturday, February 23, 2013 at 08:00

ALIX 3d2 single-board computer

The main computer on board Nostromo in the film Alien was called Mother. It seems only right that we should call our main processor by the same name.

We're looking at using an Alix 3d2 board from PC Engines as the main processor. The board has a 500 MHz AMD Geode LX800 processor with 256 megabytes of RAM. The disk drive is a CF slot and we'll probably stick an 8GB card in there, with FreeBSD installed. Technically, it'll be NanoBSD to run in that type of environment. The Alix is quite small, only 160mm x 100mm so it'll fit inside one of the compartments quite easily. It also consumes around half an amp at 5 volts, making it very low powered. We won't have much use for the Ethernet port, but will probably make that available on the deck in case we need to ssh in and change things. Likewise, there are two miniPCI slots which will be unfilled. We may stick a Wifi adapter in one of these during the sea trials.

The board has a serial port which will talk to Igor and Otto. It also has two USB ports - one for the GPS and one for the Satellite modem.

The Alix, the GPS and the Satellite modem will be powered off a 12v to 5v DC/DC converter, which can be switched on and off by Igor. As such, Mother won't be running 24×7 for the duration of the trip. The system will be powered up during daylight hours, and when course corrections are needed. The rest of the time, Otto will steer to the specified course. As the boat will scarcely manage three knots, it's quite reasonable to switch off the main system at night and let Otto steer "by the stars."

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