Subject:
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Re: 3 sensors = 8 inputs?!
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 8 Jan 1999 01:16:47 GMT
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Original-From:
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John A. Donaldson <jdonaldson@ghg.SPAMCAKEnet>
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Viewed:
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1529 times
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Mark,
It has been figured out how to get four touch sensors per input. This gives 12
touch sensors if all three inputs are used.
Using this approach, a 16 channel Analog MUX can be hooked up. Sensing the four
switch lines using Port A and the Output of the MUX on Port B. This can be expanded
even more by using a 64 Channel MUX. Using Port A & B to sense the 8 lines and the
Output of the MUX on Port C.
Since this is a Analog MUX, any combination of touch, temp,light, or rotational
sensors can be used. Using the current MindStorm Firmware, a 64 Channel would be
overkill, since you only have 32 varibles to store the sensor info as the task
scans the MUX.
John Donaldson
Mark Crosbie wrote:
> To further the thread on the limitations of having only 3 input sensors:
>
> One of the first things that occurred to me was that three inputs gives you 3
> bits of input, which means up to 8 sensors. Depending on which sensors
> trigger, you convert that to a binary number which leads you to the "logical"
> sensor number.
>
> 0 indicates not pressed, 1 indicates pressed.
>
> Input Value Logical Sensor Physical Sensor
> A B C
> 0 0 0 0 front bumper
> 0 0 1 1 rear bumper
> 0 1 0 2 left side bumper
> 0 1 1 3 right side bumper
> ...
>
> Now, the tricky part is how to build a Lego creation so that different physical
> sensors (bumpers, touch switches etc) get mapped to one of these 8 logical
> sensor values.
>
> You would need some lever arrangement whereby a bumper triggering could cause
> the correct sensor combination to be pressed. It might be easy to do if you
> have 4 bumper sensors around the edge of the vehicle. A series of axles and
> appropriately positioned levers translate a bumper movement into one of 4
> sensor combinations.
>
> Just some thoughts. If I can build it I will post a message...
>
> Mark.
> --
> Mark Crosbie http://www.best.com/~mcrosbie
> Hewlett-Packard MS 47 LA mcrosbie@cup.hp.com
> 19447 Pruneridge Avenue (408) 447-2308
> Cupertino, CA 95014 (408) 447-6766 FAX
>
> --
> Did you check the web site first?: http://www.crynwr.com/lego-robotics
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 2 Replies:
 | | Re: 3 sensors = 8 inputs?!
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| (...) Some thoughts on muxing the inputs: The rotation sensor does not mux very well. The sensor only provides analog values that are used to increment or decrement an angle counter in the RCX. If you tried to mux this you would need to change the (...) (26 years ago, 8-Jan-99, to lugnet.robotics)
| | | Re: 3 sensors = 8 inputs?!
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| (...) Yes, but using a lever based approach gives a "pure Lego" solution to the problem, which appeals to the Lego purists out there :-) Me personally, I would use the electronic approach you outlined in your email. Regards, Mark. -- Did you check (...) (26 years ago, 8-Jan-99, to lugnet.robotics)
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Message is in Reply To:
| | 3 sensors = 8 inputs?!
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| To further the thread on the limitations of having only 3 input sensors: One of the first things that occurred to me was that three inputs gives you 3 bits of input, which means up to 8 sensors. Depending on which sensors trigger, you convert that (...) (26 years ago, 7-Jan-99, to lugnet.robotics)
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