Details: Recently spotted in Hackster.io's news e-mail: Take Control Over Lego Power Functions. This quick tutorial is not purist (it involves cutting Power Functions extension wires, in addition to using an Arduino and other non-LEGO parts), but it clearly explains how to make it all work together. The Arduino platform is rapidly becoming the most popular hobby electronics and robotics platform, but it doesn't have a 9-volt output. Yes, I know we refer to the previous LEGO electrical system as 9 Volt, but the Power Functions system also has 9 volts under the hood (it's unfortunate that the official LEGO terminology doesn't provide more insight into how the systems actually work). Among the other useful tips in the article is a recommendation for a particular integrated Texas Instruments Dual H-Bridge motor driver chip (L293D), which handles the correct voltages and much of the work of controlling motors for you.
Sure, most of us will probably stick to using the Power Functions system and IR controllers to handle our Technic motor control needs, but it's great to see someone making it straightforward enough that even a novice at electronics could quickly get up and running with an Arduino- and Bluetooth-based control system instead. I may be one of the purists who prefer the all-in-one nature of the off-the-shelf Mindstorms kits, but we need to be able to do these things with more modern microcontrollers too.
These fantastic microscale tanks are practically begging us to build some large battle scenes at a smaller scale. They make excellent use of the rotation joint element from the large Knight's Kingdom figures, which has always felt like a part waiting to be rediscovered. I figured someone would find a great way to use it as space-y greebling first, but it looks perfect as a tank turret here. The complete breakdown of how they were built should enable anyone to build these, with the possible exception of the center connecting the treads - the combination of Technic, Axle and Pin Connector Perpendicular and Technic, Pin Connector Round 1L can be replaced with Technic, Axle and Pin Connector Perpendicular 3L with Center Pin Hole (which is also available in more colors so far).
