Jun 29, 2007

New Contributor!

Hi! This is my first post as a contributor of the NXT STEP blog.

I have had Mindstorms sets for about one and a half years now. My first was a RIS 2.0 kit. I liked Mindstorms so much that I bought another second handed RIS1.5 kit. And in January this year, I couldn’t resist buying the NXT set…

The robots I have built with these kits can be found here. Also, together with the people from the official Lego message boards, I launched a website featuring building instructions for NXT robots.

As some of you may have noticed, I am fascinated by LEGO brick sorting robots. I have built three of them so far. As you are reading this, number four is under construction…
The first and second used the RCX, the third was made of the NXT kit. The fourth will use both NXT and RCX.

This machine should sort 10 kinds of bricks. (5 colours and 2 sizes) To ‘see colour’, it uses a photocell and the LEGO lamp. This way the NXT is able to see the difference between black, gray, white, red, yellow, green and blue. This is impossible for the NXT light sensor.

When the folder is public, you can find some pictures via my Brickshelf.

I hope to provide some useful posts to this blog!

15 comments:

RO1000 said...

I'm glad you're becoming a contributor on this blog! I have seen many of your projects all over the place, and I am very impressed with them. I also have the 2 RCX's (1.0 and 2.0) and the NXT, so I can relate to RCX and NXT communicating together. My usename on NXTlog is RO1000. I look forward to your fourth sorter!

Rick Rhodes said...

Laurens,

We built your Brick Sorter and it works!

We made a video of it that we can send you sometime.

Rick

Robolab 2.9 said...

Laurens,

Welcome aboard!

Rick,

Just wondering, but who's "we"?

Richard

Eric D. Burdo said...

Welcome!

I have yet to build a brick-sorter. Maybe before the summer is out.

Kirk Backstrom said...

Laurens,

Welcome to the blog! I am a fan of your Chimney Climber NXT. Very novel.

Kirk

Jim Kelly said...

Laurens,

Looks like you've got some fans... welcome and hope to see more of your designs as well as your commentary and posts.

Jim

RO1000 said...

Oh yeah, if you haven't already, check out my RCX-NXT communication project on NXTlog.

Rick Rhodes said...

Richard,

"We" is myself and my wife, Fay, a contributor to this blog.

I was the primary builder for Lauren's Brick Sorter. But Fay builds and designs 99.99% of the robots at our house. (She troubleshoots the other 00.01%).

Rick

Jonathan Daudelin said...

Welcome to the team Laurens! Nice to have a fellow MINDSTORMS Forum member on board. :-)

-Jonathan

Laurens said...

Thanks for all your comments!

Laurens

P.S.

I am Dutch and my English is not perfect. I hope you don't mind if I make mistakes in my future posts.

Christopher R. Smith (Littlehorn) said...

Welcome to the gang Laurens! It's nice to see a MindStorms Forum Member over here. Have some fun!

Chris

Matthias Paul Scholz said...

Welkom Laurens!

Nice to see another European contributor to the blog finally. :-)

Matthias

RO1000 said...

I just noticed... isn't a photocell a sort of sensor that shows whether a beam of light is broken or not? It seems that you think it's a sort of color sensor... then again, I might be wrong.

Laurens said...

Ro1000,

I used this phototransistor because I didn't have any LDR's.

These phototransistors are also used in the LEGO light sensors by the way.

The resistance or 'raw value' varies due to the amount of light.

White or yellow bricks give a raw value below 60, while black bricks result in a value of 950. (Measured while using the LEGO lamp at 9 volts)

The difference between blue and green is about 200, this difference is a lot smaller when the NXT light sensor is used.

Another advantage of this method is the possibility to control the intensity of the lamp. The NXT can't see the difference between yellow and white when the lamp is at full power. When the lamp is at 60 % power, there is a clear difference: A white brick results in a raw value of about 170, while the yellow brick results in a value of 270.

Anyway, to make a long story short: This method allows you to see the difference between some colours, the NXT light sensor can’t see this difference.

I hope this made sense. :-)

Laurens

Ro1000 said...

Oh, I get it. Thanks!

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