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Subject: 
It worked! It worked! (grabber arm)
Newsgroups: 
lugnet.robotics, lugnet.loc.se
Date: 
Thu, 3 May 2001 20:25:14 GMT
Viewed: 
720 times
  
Tonight, I finally fulfilled my dream I had since I first came across LEGO:

Building a robotic arm, by myself, without instructions.

When RIS came out a few years ago I thought "This is it. Now I can not only
build my arm, I can program it to do all sorts of neat stuff."

So when we were asced to do a science project in school, my choice was obvious.

Three months of planning, building, desperation, joy, happiness, frustration
and that LEGO feeling was what it took.

I originally planned to program the arm in NQC. I thought I could learn NQC.
But I couldn't. So I had to program it in RCX code instead, which I was not
first happy about, because I thought I couldn't make it to do something good
enough.

The arm can move much like a human arm. Movement around five points and a
pneumatic claw that opens and closes.

"Well, what does it do, then?"

This is another thing I thought would be a good thing to do in NQC, that
wouldn't be possible with RCX code.

Six objects (three black, three white) are placed in fornt of the arm. It
grabs one, analyses the colour, then puts it to the left/right, depending on
colour. "So? I can do that in RCX code with my hands tied on my back!" Yeah,
I know. So I added one more thing: The arm must remember if it is the first,
second or third black/white object it picks up, so it can place the objects
in two tidy rows. This, I thought, could not be done in RCX code, where you
could not define variables.

I was proved wrong.

When I realised I had to do the program in RCX code, I got really depressed
and thought "This is not going well at all."

Then I got an idea.

My arm uses 2 RCX units. 1 counter in each unit, two units = two counters,
one for black and one for white!

So I started programming it.

It seemed hopeless at first. But I kept going.

20 minutes ago, I made the two "beta" versions of the program for RCX1 and
RCX2. I downloaded them, ran the program, and to my amazement the program
worked flawless!

Two rows, each of it's own colour, no dropped objects, no bugs, just a
clean, simple, neat and tidy program!

I felt so satisfied. I had proven myself wrong, too. I neever thought I
would be able to build this arm.

Tomorrow's the presentation of the project. Wish me luck! (You know it. It
always works perfect when you're alone and nobody sees it, and when you're
standing there, in front of the crowd, it doesn't work.)

Now I'm hooked on this. I'll build robots for the rest of my life.

--Tobias



Message has 1 Reply:
  Re: It worked! It worked! (grabber arm)
 
Congratulations and best wishes on your presentation! Please post pics ASAP!!! ;-) Cheers, Carl Jagt (...) (23 years ago, 3-May-01, to lugnet.robotics, lugnet.loc.se)

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