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Subject: 
Re: Why Java for Robots
Newsgroups: 
lugnet.robotics
Date: 
Fri, 20 Jan 2006 12:45:19 GMT
Original-From: 
PeterBalch <PeterBalch@#saynotospam#compuserve.com>
Viewed: 
1961 times
  
Bruce

I guess we're going to have to differ on this one.

We're talking about completely different classes of robots. This is a Lego
discussion group and the vast majority of people who post here use RIS or
NXT (soon) or computers of equivalent size. Sure, there are people like you
who use Lego just for the mechanics and people like me who hardly use Lego
at all but we're the minority.

You're interested in high-level "intelligence". I'm interested in bringing
hobby (i.e. home education) robotics to the masses. Lego certainly fits
into the category. But I probably mean parents who will buy a $20 kit for
their child but not a $230 Lego set. Or gadget-lovers who have found that
Robosapiens is brain-dead and want more intellectual stimulation. My
proudest creation is a complete programmable robot for $10 - I'd love it if
they were produced in India for $5 so every school there could afford them.

Java isn't a good fit for $1 PICs. I never said it was. But how
interesting a robot can you build with a $1 PIC? Answer: about as
interesting as the robots everyone has been building with $1 PICs for
the last 10-15 years.

$1 is a bit low but a $5 PIC is quite capable. I don't think that any robot
I've seen that has a 16F877 uses anything like the full potential of the
chip. Sure, you can't do image processing be neither can a termite. There's
a lot more to robotics and AI than the big number-crunching applications.
No-one has produced a robot that's 1% as capable as a termite. That's not
due to lack of processing power but simply because we don't know how to do
it.

OO design beats subroutines when you must have polymorphism and • inheritance
But I'm unable to see any advantage elsewhere.
Encapsulation is a big one for me.

Encapsulation does not require OO design. Only polymorphism and inheritance
require OO design.

If you are determined to limit yourself to 10-year old $1 parts
making up a $50 or $100 brain, you are right -- Java, image
processing, 802.15.4, ethernet, and many other things will be impossible.

Actually, ethernet is possible on a PIC (I've done it and so have others).
And the CMU-cam doesn't use much h/w capability.

It is such a pity that tiny-Java is impossible. When Java was first
announced, it was touted as a language for all processors: from controlling
a toaster to controlling a power station. Now it appears that your toaster
must have half a Meg of memory! People pay me to design cheap circuits that
use cheap PICs. When Java appeared, I was sure I'd be using it in a few
weeks. But if I told all my clients that their circuit needs a few hundred
Kbytes I soon wouldn't have any clients. What went wrong? It doesn't have
to be that way - a tiny-Java is possible (I think). Should someone write a
tiny-Java compiler for the NXT? I'd love it if they did. Instead, we'll get
Yet Another C Compiler.

I want to be convinced that Java is a Good Thing and I occasionally promote
these discussions in the hope that someone, such as yourself, who is an
expert and enthusiast, will convince me.

Have you convinced me there's any reason at all to switch from Delphi to
Java? No. (From C++? Yes, switch today.)

Have you convinced me there's any reason to use Java on small robots? No.
It won't fit.

Have you convinced me there's any reason to use Java on a big robot? No.
I'll just fit a laptop and use Delphi.

Sigh.

Peter



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