Two decades of LEGO Mindstorms

I was listening to a Hanselminutes podcast episode about LEGO education's new Spike Prime set, when I heard something quite interesting: After generations of C-based firmwares for the LEGO Mindstorms family of intelligent bricks, the Spike Prime actually runs a MicroPython micro-controller. I feel joy but at the same time I feel a bit old, to think how much we've advanced so that now any kid can easily build and code a robot using Python...

When I was young, I fell in love with the original Mindstorms, and since then, I've collected all three generations (four if we count the Micro Scout). While I gifted most of robots and pieces last year to an electronics and robots lover friend, I still remember the fun weekends and nights learning how to build the robots and how to modify the firmware to code them with my language of choice. Steps that you don't need to take any more it seems :)

If you haven't heard before about the Mindstorms LEGO family, hackeducation.com has a small but nice technical summary, and I will provide links to the Wikipedia relevant versions too below.

LEGO Mindstorms Micro Scout

Let's be honest: The Micro Scout was a glorified motor and IR receiver that came with the pieces and instructions to build a cool AT-AT with the Dark Side Developer Kit, or an even cooler R2-D2 with the Droid Developer Kit.

I don't keep decent-quality photos of it but a photo from the instructions is good enough:

LEGO Mindstorms RCX

The RCX was the first generation, and it was released in 1998 but I got mine either on 1999 or 2000, I don't remember exactly.

It was a v1.5 (there were v1.0, v1.5 and v2.0 revision). I coded it in C at first, then in C# with LEGO.NET. It was the most entertaining one to "hack" as there was no official custom firmware support, plus initially I had to connect it to my PC via a serial port. I bought a USB IR tower later and what a difference! It also meant more portability as serial ports disappeared few years later.

I had all expansions I could get my hands on, from [Vision Command(https://lego.brickinstructions.com/lego_instructions/set/9731/Vision_Command) (whose camera was terrible, but still great to do quick'n easy color recognition back then) to Exploration Mars (the spring-based suspensions and different sized wheels were awesome), plus some extra LEGO Technic pieces.

At the end of the instructions you could see the back of a modified R2-D2 using the RCX brick. I don't keep any good quality photos of my build either, but it was exactly the same as the one in the following image. Note that the R2-D2 head is turned, we're shown actually the back of the droid, it is like a V-shape seen from above, with the tip forward, not backward:

LEGO Mindstorms NXT

The second generation of Mindstorms bricks, the NXT, allowed a much easier development. If I recall correctly, the specifications of the commands were published, so interacting with it was very easy. I got mine the year it was released, in late 2006, during a trip to Australia.

I coded on it with C#, using NXT.NET but also directly from Microsoft Robotics Developer Studio. As you can see not only you didn't needed a custom firmware, it also provided an IDE-friendly interface, especially since you could send the data and commands via Bluetooth. You could even use a PocketPC PDA to remote-control it.

LEGO Mindstorms EV3

The EV3 is the current generation of Mindstorms, released in 2013.

Much more powerful, it is so hacker-friendly that supports booting custom firmwares via Micro-SD card (instead of overriding the built-in one), LEGO has published the full source code of the operating system, and it is also compatible with the NXT sensors! It has really very few limitations to what you can do, except of course your own imagination.

With this brick I coded mostly using the bricks UI, as it is so powerful it was handy to just drag & drop blocks and change a few parameters (by the way, you can code programs just with the own brick on its own!). But for a change I started building a NodeJS library to program it. I didn't went too far with the project, but what I built worked nicely and was a fun exercise in reading the operating system's source code and adapting it to Javascript. Again, communication was done via Bluetooth, and apart from the dual-firmware, the main "hackable highlight" was that, this time, we had the full source code of the operating system available.

I skipped trying to update my R2-D2 robot with the NXT version, so it was due for an update. My last project before deciding to stop playing with the Mindstorms family was an EV3-based R2-D2 prototype:

The front is missing some panel or cover, but I wanted easy access to the steering wheel/leg until was working as desired. It was missing also the famous beep sounds (which you can now add to the EV3 too, as it includes a speaker and memory for a few sounds), but is mostly functional and moves forward, backwards and rotates (plus can be controlled remotely via Bluetooth).

I never got to build real sumo, racing or maze-solving robots, but I feel that with Mindstorms, I've spent two decades doing almost the same. I forgot about the hardware and soldering aspects, and focused on the fun of building the robots themselves. Thank you LEGO for providing us with such great tools and being so developer-friendly.