Subject:
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RE: Elimating the need for the IR tower
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 11 Jan 2001 18:25:03 GMT
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Original-From:
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John Barnes <barnes@=StopSpammers=sensors.com>
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Viewed:
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717 times
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Ken Warren wrote:
>Has anyone actually got a circuit diagram? I'd be most interested to see it
>as I've got the Robot Development Kit and it doesn't come with an IR tower
>and Lego's promise of 'available Autumn 2000' for the upgrade seems to have
>failed.
There are all sorts of dire consequences for reverse enigneering things these
days. But rest assured, the tower is not that complex.
Last night, after yesterdays flurry of messages about the this thread, I
built up
a self powered "tower". As I expected, there is adequate power to be had from
your typical RS232 control lines to run it.
I obtained a range of about 6 inches which is perfect for "short range".
The only
problem I had was to make sure the RCX is set to short range. If it is set
to long
range, its output seems to overload the tower sensor at such distances. (The
RCX's IR output in long range mode is very very bright!!)
The ultimate test is to be able to download the firmware, especially
firm0328.lgo
which is by far the largest. I used a 100 watt light bulb as an ambient
light source
to determine the sensitivity to ambient light. If the bulb was closer than
six feet,
then the download normally failed. If it was closer than two feet, then simple
polls failed also. As a comparison, the official Lego tower is not a lot
better. You
cannot download the firmware with a 100 watt lightbulb two feet from the RCX.
With the the nearest 100 watt lightbulb about 8 feet away, I had no problems.
I am sure that, appropriately shaded, these figures can be changed, but my
prototype setup wasn't easy to shade ;)
I will try to get the schematic into a suitable format asap. I ensured that
every part
is obtainable from Digikey. The testing was done with a Compaq laptop which has
a fairly weak RS232 output port, so I am assuming that beefier PCs will be ok.
(I tested the circuitry powered from a 9 - 12 volt supply too, and it works
just fine.
My Compaq only makes +/- 5 volts on its outputs under a 1k load.)
JB
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Message has 2 Replies:
 | | Re: Elimating the need for the IR tower
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| YOU ROCK! let me know when something happens and i'll see what i can do about getting a parts kit ready for order from the industrial electronics. a no-power ir tower is exactly what i was looking for for programming from my PSPC bu i think that i (...) (24 years ago, 11-Jan-01, to lugnet.robotics)
| | | Re: Elimating the need for the IR tower
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| What happened with this John B. ? Where I can get some schematics ? It would be great if I could build an Ir Tower (or something to program my scout), since I can't get anybody to ship this things to where I live (Argentina) Tia, (...) <> (...) (24 years ago, 9-Apr-01, to lugnet.robotics)
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