As some of you know I have a fledgling company that sells a weather station that I designed. Basically it is software that does a nice job of plotting various weather parameters over time (see current weather in Truckee, CA). In the past I have done this in Basic on cheap DOS boxes, but a year ago I rewrote it all in squeak and looked around for a cheap PC powerful enough to run Squeak. In selecting a suitable processor and making up a Linux environment, I engaged the help of Michael Rueger.
Our first shot at this in the spring of 2002 was the Shuttle, a low-cost PC with motherboard, to which we added inexpensive processors and hard disks. We (mostly Michael) got it all working, but the fans were way too loud. There were three of them: one for the processor, one for the power supply, and a third for the cabinet in general. We added tweaks to slow them down, which helped a lot, but it took a lot of time (think money) to prepare each unit. Even after doing this, it turned out that many of the hard disks were noisy. To top it off a number of the units expired in the field, possibly due to the fan mods, but we're not sure.
The main reason we did not pursue the exact causes of failure was our discovery in the spring of 2003 of a seemingly perfect replacement built around the new Mini ITX boards.
The Mini ITX
What is Mini ITX? Briefly it is an extremely compact (16x17cm) implementation of a Pentium-compatible motherboard, designed originally for the needs of the set-top box market. The configuration is quite complete, featuring Ethernet, 2 USB ports, RS232, printer, display, mouse, keyboard, video out and stereo sound in and out. In addition, the design is very low on power so that the 533MHz units can run with no fan at all. You can imagine how good this looked to Michael and me.
A particular unit (see the Silent Station) is available with an adaptor that allowes the use of a Compact Flash card in place of an IDE disk drive. In this configuration, all software could be cloned on a simple flash card, and booted to run with no moving parts except the boot button and the electrons. The price: around $230 in single units.
The software - lean Linux and Squeak on a flash card
We have now assembled a software kernel that includes a lean Linux base (modified by Ian Piumarta to provide direct frame buffer display), and a full Squeak 3.6 image and VM, all fitting on a 32M CF card with about 10MB left over. For my needs this is an ideal solution: buy a Silent Station, stick in a CF card, and resell it as a graphical weather station. It's especially nice that the Silent Station uses a 12v supply, which means you can hack together a 5-hour UPS from a lead-acid battery and a trickle charge circuit.
Availability
In addition we are making the entire configuration available so others can build cool embedded applications using Squeak. The Linux scripts and documentation as well as a mailing list can be found at http://www.fflinux.org. As soon as the dust settles and I've had some chance for testing, I will provide 64M flash cards with a full and current Squeak development system for a nominal cost. These can be dropped into any Mini-ITX box with a CF adaptor. If you don't have one, the adaptors are available from SolarPC and elsewhere on the web (search: Flash IDE adapter).
The Mini ITX standard has a growing and fanatical following of computer "hot rod" style enthusiasts (see http://www.mini-ITX.com/). Now we have a complete software development and delivery package the size of a matchbox that can be plugged into any of these boxes and run for decades with no noise and high reliability.
Outlook
Could there be more? Yep. It's called Nano-ITX (see Nano-ITX). All the above on an 11x11cm board with a 1GHz processor. Announced by VIA but not yet available. They'll probably be pricey for a while, too.
- Dan Ingalls
Now an even smaller version squeak could fit on. A finger sized computer. http://gumstix.org
