Subject:
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Re: The IR BALL
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 30 Aug 2000 22:31:14 GMT
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Highlighted:
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In lugnet.robotics, "Patel" <hhppatel@md4.vsnl.net.in> writes:
> Hi There , below is a mail i got=20
> i wanted some info in the end..
> we used a simple transparent plastic ball with a diameter of 4-5cm
> (about 1,5 inches), which contained the IR-emitting LEDs and their
> batteries. As far as I can remember, the circuit was very simple, and we
> put *a lot* of IR LEDs because we soon discovered that the critical
> point of the whole project is to have the robot locate the ball with
> sufficient accuracy. You see, an IR LED pointed to the ground is no way
> good and the detection range of the standard Lego light sensor is not so
> wide. I seem to remember that we also put some non-IR LEDs in the ball,
> but you'd better ask Marco Berti (marco.berti@itlug.org) who built the
> ball and who is, by the way, an expert in batteries.
> It's also very important to have the right environment, as the IR light
> can be easily reflected by the background or by other objects, and
> hamper the good behaviour of the robots. We also put a black/white
> gradient sheet in the playing field, just under the robots, to let them
> easily (?) find their way in the right direction.
>
> This project seems very intresting=20
> Can you tell me how to build this ball with IR leds?? ??
> what are the requirments and how will the lego detect the signals?? from =
> the ball???the programming bit also.
> Dr Patel
Hi
As Mario and Giulio made my name I have been forced to beat my laziness and
upload some picture of the IR emiiting ball (sorry it has not been made with
Lego parts!) and of the robots.
You may find the ball picture here
http://www.brickshelf.com/cgi-bin/gallery.cgi?f=1223
The real problem was to have enough "IR light" from the ball.
I solved the problem "squeezing" 28 IR led , 6 high bright led , 4 x 350 mAh
sanyo nicd cells , a recharge plug and a switch inside a 5 cm (2 inches)
transparent ball (stolen to my son Carlo).
This give enough light power for the IR sensor to detect the ball up to 3
meters in a normal room light and a working time of about one hour and half
when you have fully charged the nicd.
Also have a look at this message
http://news.lugnet.com/robotics/?n=12276
and feel free to contact me if you need more info
Marco
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Message is in Reply To:
 | | The IR BALL
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| Hi There , below is a mail i got i wanted some info in the end.. we used a simple transparent plastic ball with a diameter of 4-5cm (about 1,5 inches), which contained the IR-emitting LEDs and their batteries. As far as I can remember, the circuit (...) (24 years ago, 31-Aug-00, to lugnet.robotics)
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