IEEE Spectrum November, 2016 - 21

A DIY Lego
ControLLer
A low-cost wAy
to progrAm lego
mAchines

f you want to explore coding with Lego bricks, there's one major option:
to use a kit from the company's well-known Mindstorms robotics line. Mindstormsbased machines are built around the Intelligent Brick, which can be programmed
using Lego's graphical programming environment or one of a number of third-party alternative languages. But Lego also makes a collection of motors, connectors, lights, and infrared receivers collectively sold under the label of Power Functions. In place of a programmable brick, the Power Function line includes a handheld controller for transmitting command signals. I wondered if it was possible
to use a Raspberry Pi to replace the handheld controller, taking on the role of an Intelligent Brick. This would have some advantages.
With programs being created on the same device used to control Lego constructions, it would eliminate the need to download the programs to the brick, speeding up development. The US $40 Pi is also a lot cheaper than the $190 Intelligent Brick. I also wondered if
such a setup could be used with MIT's Scratch, a free visual programming environment aimed at children. Scratch extensions are available for use with the Mindstorms brick, but they require altering the brick's firmware, and I wanted to try something simpler. As I discovered, most of the code required for controlling Lego toys using Scratch is already available as open source software. What was

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Table of Contents for the Digital Edition of IEEE Spectrum November, 2016

IEEE Spectrum November, 2016 - Cover1
IEEE Spectrum November, 2016 - Cover2
IEEE Spectrum November, 2016 - 1
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IEEE Spectrum November, 2016 - Cover3
IEEE Spectrum November, 2016 - Cover4
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