Subject:
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Re: multiplexing Spybot inputs?
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Newsgroups:
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lugnet.robotics.spybotics
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Date:
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Sun, 8 Jan 2006 20:36:36 GMT
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Viewed:
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10811 times
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In lugnet.robotics.spybotics, Joe Strout wrote:
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In lugnet.robotics.spybotics, Steve Hassenplug wrote:
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On Thu, November 3, 2005 12:14 pm, Joe Strout wrote:
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It occurred to me that one might fit some sort of light sensors on top of
some of the six LEDs on the Spybot’s top side, and use this to select an
input channel to route information from any of a number of sensors to the
VLL sensor.
Has anybody tried this yet? Any thoughts on how well this would work, or
pointers to a suitable multiplexer circuit?
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You can control the VLL output of the spybot, so you should be able to just
connect something much like the programming cable, and get two-way
communications.
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Two-way communications with what? Are you picturing some sort of
microcontroller that monitors all the extra sensors, and reports values to
the Spybot upon request?
That sounds beyond my capabilities, as well as probably not as fast as the
multiplexer approach. With the latter, to read (say) one of sixteen inputs,
you just set the four LEDs to address the desired input, then take a reading
from the VLL.
To communicate with a microcontroller, you’d instead have to send the
request, then wait for a reply, both using a serial protocol. I imagine that
for some applications, polling the sensors as fast as possible would be
helpful -- but I haven’t actually done the math, so maybe this isn’t actually
relevant.
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Here’s a good VLL page:
http://www.elecbrick.com/lego/
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Thanks — I’d seen that before, but hadn’t realized its relevance to
Spybotics. Hmm... that suggests all sorts of fun things one might do, like
printing VLL codes onto a transparent wheel which you then spin in front of a
light (using a standard LEGO motor), making a “beacon” that not only
advertises its presence but transmits information (identity or commands) too.
Best,
- Joe
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Some time ago, I have sugested the use of the VLL port to make an interface to
connect a couple of lego light sensors to the spybot. The ideea was to have an
analog device (powered by a 9V bov) that would just switch on a sensor, then
switch it off and turn on a LED that would shine proportional with the amount of
light sensed by the light sensor. This LED would be connected to the spybot’s
light sensor, which in turn would make the spybot light sensor sense about the
same light intensity as the Lego light sensor. Now using the spybots LED from
the VLL port, and having a fototransistor connected to it, it can trigger a gate
to select which Lego light sensor would be read. I hope it makes sense...
After playing with other microcontrollers, I just realised that this aproach is
too complicated. A simple 8 pin PIC would do the trich much easier and is not
more expensive. I did not built it yet. Other projects got in the way, but
eventualy I will build one.
Gabe
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Message is in Reply To:
 | | Re: multiplexing Spybot inputs?
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| (...) Two-way communications with what? Are you picturing some sort of microcontroller that monitors all the extra sensors, and reports values to the Spybot upon request? That sounds beyond my capabilities, as well as probably not as fast as the (...) (19 years ago, 3-Nov-05, to lugnet.robotics.spybotics, FTX)
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