.Net On Lego Mindstorm

troop23 writes "A blog posting by Benjamin J. J. Voigt says this "The University of Potsdam has a project to develop a .NET VM for the Lego Mindstorms system. Lego Mindstorms just got a higher priority on my shopping list!" While the thought of using .Net to program Lego Mindstorms may not be palatable, having a mainstream dev environment sure is." Perhaps Mono would work just as well.

Java VM

[Anonymous Coward]

A Java VM exists already. It's called leJOS.

FIRST Lego League

[His Eminence]

http://www.usfirst.org The FIRST lego league might have use for this, but I doubt middle-schoolers would be interested...

If you want C/C++ the best thing to use is

[Anonymous Coward]

BrickOS. It's faster and has many more features than NQC (a competing language) which uses the proprietary Lego firmware for the RCX.
BrickOS has its own firmware and supports threading and all the basic C/C++ functionality.

See:

http://brickos.sourceforge.net/

Re:Why?

[Anonymous Coward]

The .NET VM, which was originally OmniVM from Colusa [thefreedictionary.com] (who microsoft bought in '96); is a really nice design - more flexible (able to run more languages easily) than the Java VM.

C/C++ (which the parent article asked about - is really just a language (like C#) and not a runtime). The biggest distinction is that the runtime will address issues like loading code dynamically. Had they simply ported C/C++ there would have been a whole lot more architecture-specific battles to fight (a.out vs elf, etc).

Re:Why?

[gabebear]

There is a replacement firmware that lets you use C++ compiled binaries BrickOS [sourceforge.net]. works well, I'm about to re-release a web interface for BrickOS. The old LegOS compiler is Here [mersenne.com].

Re:Is Lego back on firm financial ground?

[Coward, Anonymous]

They expect to break even [lego.com] this year.

NQC?

[MrFlannel]

There already is a C compiler (well, its very close to real C) its called NQC (Not Quite C). You can buy a book about it. Google yields this as its site. http://bricxcc.sourceforge.net/nqc/

Why?

[Anonymous Coward]

Why not use Lejos for Java [sourceforge.net]?

Developing for the Mindstorms brick

[mollymoo]

I've been playing with Mindstorms for a few years. There are basically two approaches used for programming the brick: Using the Lego firmware and replacing it. The graphical Lego programming language provided with the kit compiles to bytecodes which run on the Lego firmware. It's not very fast or flexible. The brick is a Hitachi H8 at heart, so writing code for it is preferable if you know how.

NQC (Not Quite C) is compiled to Lego bytecodes. BrickOS programs are compiled to H8 with gcc. There are also Forth and Java environments.

Given the range of options available (for *nixen, Windows, Mac...) I'd have to say in this case "mainstream" must mean "Microsoft".

Re:Is Lego back on firm financial ground?

[meringuoid]

There's a Lego store recently opened in Birmingham which has some truly amazing stuff. Yes, there's a lot of that awful Bionicle stuff and suchlike with special pieces and so on, but there's SO MUCH COOL STUFF!

I only just got out of there yesterday without buying a giant orange robot looking just like EVA-00, with instructions for four or five alternates. They've got a pick-and-mix section at the back where you can take a big tub - like the ones you get drinks in at the cinema - and fill it with your choice of pieces. Classic models - like the pirate ships your parents would never buy but you can now afford yourself! muhahaha!

Um, sorry, got a bit carried away... but I think Lego are getting the idea lately, and realise what their market really is.

Re:IDL Libraries?

[omicronish]

Great now you'll have to include 60 MB of IDL code to run any program. Where do these ideas come from? Who would think to port a bloated server app development API to a portable device. .NET is loved by managers who think they can dumb down their server side code so any H1-B can do it, that's about it. Nobody even uses .NET for desktop apps, so where'd the idiotic idea that it would take off in a portable environment come from. The main reason I refuse to use .NET for desktop apps is the 60 MB IDL needs to be included, better to VB 6 or anything else for that matter. M

I would imagine most of that 60 MB is the .NET framework library, only a fraction of which you'd really need to port to portable devices. Stuff like ASP.NET, Winforms, the entire System.Drawing namespace probably wouldn't be needed. At the very core you'd only need an execution engine, which is basically an IL interpretor, and perhaps a partial implementation of the System namespace. Yes, there's bloat, but certainly nothing like 60 MB, and for something non-critical like Lego Mindstorms, the bloat would be acceptable to me.

Re:Is Lego back on firm financial ground?

[mark-t]

They are not pulling the plug on Mindstorms.

See here (January 2004) [lego.com] and here (March 2004) [lego.com]

There was quite a kafuffle shortly after Christmas of last year when LEGO announced their shift in direction. Quite a large number of people were very concerned that LEGO would be dropping Mindstorms. Flurries of posts on LEGO discussion lists and even letters directly to LEGO were filled with remarks much to the effect of "What?!?!? Why is LEGO doing this?" LEGO issued the January press release above to abate those concerns. Also mentioned above is a March release in which they restate the Mindstorms is one of their core products and they will *NOT* be dropping it.

First Lego League [firstlegoleague.org] is also very dependant on Mindstorms, and I don't think they're going away anytime soon.

Use Ruby

[Anonymous Coward]

There's a Ruby interface for Lego Mindstorms here:

http://rubyforge.org/projects/lego-mindstorms/

Re:Why?

[xenocide2]

Funny story about Java. Originally it was designed as a language for embedded systems, back when it was called Oak. There, the idea of a VM to provide various system tasks is actually quite tenable. The idea being, they write the VM once for a platform, and you're free to start prototyping the code before you finalize your choice of board.

Reality sunk in, and the embedded systems market just didn't like the idea. Training people in the new language was going to be expensive (compared to the status quo), and most were skeptical about the utility of a VM. The concern being that you typically need or want access to specific available resources that an abstract interface can't provide.

Seems marketing shifted gears and started pushing applets and the web. Went okay for them in the end, I guess.

Re:IDL Libraries?

[SilentChris]

The article doesn't mention, but they could very well be using the .NET Compact Framework, which is a hell of a lot smaller and doesn't contain any of that server stuff. There's Winforms (which they wouldn't need) but the rest would be salvagable for a couple of lego bricks.

As for using .NET for desktop apps (*shrug*), I've sure seen it. I have to deal with a lot day-to-day, and if it's a choice between pounding out a few objects and events in .NET vs. installing the latest Java VM on everyone's machine to run one app, I'll take the .NET route. Considering .NET will practically be the Official Framework (tm) for Longhorn, it'd be good to learn it now.

LeJOS?

[Anarioch]

Nice to have a mainstream dev environment? LeJOS [sourceforge.net] is a Java VM for the brick and will let you run Java programs on it - and it's been around for a long time now (I've been using it for a couple of years). Seeing some of the things people have done with it is impressive - a Rubiks cube solver, vision systems using RPC stand out.

Re:IDL Libraries?

[TummyX]

Uh, I think you mean IL. IDL = "Interface Defninition Language" whereas IL = "Intermediary Language". Getting the teminology wrong when you're trying to sound smart and informed isn't a good idea.

FYI, the .NET redistributable is 23MB, the compact framework is 12MB (and that includes VMs for all supported processors). Portable.NET (DotGNU's runtime) can fit on a single floppy.