Subject:
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Re: More then 3 Lego Light Sensors at a time?
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 11 Mar 2002 16:17:40 GMT
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Viewed:
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909 times
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An active multiplexor would solve your problem. Take a look at the one sold at
www.mindsensors.com, it allows you to hook three sensors to one input port.
The sensors can be of any type. They don't work directly with legOS, but I've
summited a legOS patch which you can find in the patches tab of the legOS
project at sourceforge http://sourceforge.net/projects/legos/ which fixes this.
A few words of warning. I spent a few weeks playing with these things and was
very impressed with them, but found a few potential problems.
1. If you use a touch sensor with it, and the sensor is pressed it will block
the multiplexor from switching. This can be easily overcomed by adding a light
sensor.
2. If your RCX has motors attached and they are under load this can cause the
multiplexor to have trouble switching. With fresh batteries this doesn't seem
to happen as much.
3. If you are using my legOS patch the values read from the sensors are only
updated 2-3 times per second. The driver I wrote contantanly switches thought
the muxed ports, and this is the fastest rate the mux hardware can achieve.
4. Rotation sensors aren't fully functional with the multiplexor under legOS.
In legOS the rotation sensor driver samples the value from the roataion
sensor a few times a millisecond and this rapid sampling allows the driver to
watch the state transitions and count revolutions. Due to how infrequently a
rotation sensor attached to the amux would be read (point 3 above) with my
driver, they would be unlikely to work. Because of this I didn't integrate the
rotaion sensor and multiplexor drivers to work together, so for now it just
plain won't work. It should be possible to modify my driver to switch to a
given port and then read from it for a long time, in this case you might be
able to use the rotation sensor. With things in their current state you can
still read the raw data from the rotaiton sensor to determine which of the 4?
quadrents it's in.
So lots of warnings, but I still recomend the device.
mark
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Message is in Reply To:
 | | More then 3 Lego Light Sensors at a time?
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| Hello all, I have been lurking for a while, and tried doing a little searching on the net, and have not seen this anywhere. Is it possible to use more then 3 standard lego light sensors at a time? I have seen that there are configurations for (...) (23 years ago, 11-Mar-02, to lugnet.robotics)
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