Color Sensor

[klmichae]

Can a color sensor be used by NXT 1.0? We didn't see any blocks for it in the Lego Mindstorms NXT software.

If it can, does anyone have any hints on how to treat it just like a light sensor?

Thanks.

---Karen

[GWhizNonKid]

I'm pretty sure that the color sensor requires at least version 2 of NXT-G and firmware to match. I'm also pretty sure that the color sensor holds no great advantage over the light sensor for this year's challenge. However, if you get the sense that your kids will be inspired to experiment with a color sensor AND your budget ($ and time) will allow it, then you should take the plunge. Please let us know the results of your experiments. I'd like to see a linefollower or rainbow navigator using the device.

There is no "I" in "team" but there is and "I" in FIRST.

[Dave Parker]

The color sensor requires either the NXT 2.0 retail (8547) software, or NXT-G 2.1 from LEGO Education. You can upgrade LEGO Edu's NXT-G 2.0 to 2.1 via a web download (which for some reason I can't find right now).

However, I would say that for FLL (at least the Body Forward robot game in particular), the color sensor has no real advantage over a light sensor, and in some important ways is worse. So don't buy one if you are hoping for a straightforward advantage. But go ahead if you want to experiment and try some new stuff!

The Color Sensor's color sensing feature is actually pretty weak (can only discriminate 6 colors and only if the conditions are right), but it can also be used in "light sensor" mode, in which case it is very similar to the standard light sensor, except harder to use accurately because calibration is not supported, and also less sensitive (no "raw" output). But once you figure it out, performance for line following and the like are very comparable between the two.

<beginner tidbit>
Having said that, for beginner and younger teams who have not yet come to understand the light sensor (confused by calibration, "<" vs. ">", mystery numbers, etc.), the color sensor may be a more intuitive way to do some basic color-seeking on the mat. Assuming the placement and light conditions are cooperative, you can simply say "wait for black" and the like, which is intuitive to the kids vs. the number-oriented approach of the light sensor.
</beginner tidbit>

<advanced tidbit>
There is a potential real performance advantage to the color sensor if the following situation would arise: If you were trying to find or follow, say, a red line against a white background, this is hard or impossible with the standard light sensor because it sees red just like white with its red LED. But with the color sensor in light sensor mode, you can choose red, green, or blue illumination for the LED. So to follow red against white, you could illuminate in blue, which would make the red look like black, leading to excellent contrast against white.

See the utility program at http://www.nxtprograms.com/NXT2/light_meter/index.html
if you want to experiment with this.

If your team looks around, they may find some potential uses of this technique in Body Forward... but it's their call if it's worth it.
</advanced tidbit>

Dave Parker
www.nxtprograms.com

[Jeff Bartig]

The NXT-G Education 2.0 -> 2.1 upgrade can be found here. Firmware 1.31 can also be found on this page:

http://www.lego.com/education/school...4&l4id=3_2_4_2

Jeff

[RoboDesigners]

Originally Posted by Jeff Bartig

The NXT-G Education 2.0 -> 2.1 upgrade can be found here. Firmware 1.31 can also be found on this page:

http://www.lego.com/education/school...4&l4id=3_2_4_2

Jeff

At this site you can also find the color sensor block. It is spelled Colour, though... (if you want to do a search of the page)