The Hardcore Hardware Engineering Behind Sifteo Cubes

Sifteo 2nd gen graphic demo.

If you are any kind of hardware hacker, you need to go read this long, exciting, and technically exhaustive piece over on Adafruit by one of the engineers working on the 2nd gen Sifteo cubes to make them an awesome, wirelessly-connectible gaming platform. It looks at the challenges faced by designers on a day-to-day basis, and ultimately demonstrates how creativity and innovation go hand-in-hand.

A teaser:

The original set included a 72 MHz ARM processor in each cube. It is roughly equivalent to the chip that powers the LeafLabs Maple board. This sounds paltry compared to the gigahertz processor in your phone, right? We’re so used to being surrounded by devices with chips powerful enough to run Linux, Android, or iOS. These chips aren’t even that expensive on their own. A top-of-the-line mobile phone CPU costs maybe $20. A more modest 375MHz ARM might be only $7 in quantity. Surely in a consumer product that costs upwards of $100, we could afford to ship three or four of these chips, right?

Not even close, unfortunately. In the bridge analogy, that’s only the cost for the pavement. You need support structures: power conversion, batteries, battery chargers, memory, programming infrastructure. These are significant costs, especially batteries and RAM. Now you multiply everything by a markup factor to account for the cost of assembly, running the factory, supporting the retailers. Every dollar you spend on the CPU turns into at least three dollars of cost to the end user.

Even that modest 72 MHz ARM was too heavy. We couldn’t afford a one-size-fits-all design. We needed to build a lightweight bridge from the ground up, using parts that would get the job done without overburdening the rest of the structure.

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