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Subject: 
Re: ideas for a RIS 2.0
Newsgroups: 
lugnet.robotics
Date: 
Tue, 24 Aug 1999 19:17:47 GMT
Original-From: 
John A. Tamplin <JAT@LIVEONTHENET.COMnospam>
Viewed: 
700 times
  
On Tue, 24 Aug 1999, Robert Munafo wrote:

In lugnet.robotics, John A. Tamplin writes:
On Tue, 24 Aug 1999, Berger, Kurtis (I) wrote:
I'd be interested in a semi-analog touch sensor...  ie: press the button a
little, it shows a low raw value [...]

The standard Lego sensor already varies depending on how far it is
depressed. [...]

If that were true, then the following multi-touch-sensor adapters would not
work:

  http://www.lugnet.com/robotics/?n=1897

  http://www.plazaearth.com/usr/gasperi/3rmux.htm

Put a touch sensor port into raw mode and watch the values you get as you
gradually depress the sensor.  There is not a sharp cutoff like there is
with a typical contact switch.

I tried building a touch sensor multiplexor, but I was unable to reliably
get even 3 to work because the minimum resistance is quite large and
because the transition from infinite to that minimum resistance is quite
gradual.  By switching to micro-contact switches, I was able to reliably
get 4 switches to work, including operating with a wide range of battery
freshness.

If you arrange that the touch sensor is either fully depressed or not
depressed at all, you can still make it work (as on Gasperi's page).
However, you have the problem that one of the touch sensors partially
depressed can result in a false indication that a different switch is
pressed.  For some, this might be acceptable.

John A. Tamplin LiveOnTheNet.COM, Inc.
jat@LiveOnTheNet.COM 2104 West Ferry Way
256/705-7007 - FAX 256/705-7100 Huntsville, AL 35801

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message has 2 Replies:
  touch sensors aren't just switches (was Re: ideas for a RIS 2.0
 
(...) Wow. That's pretty darn disappointing. I even bought extra touch sensors to use in multiplexed designs (but I haven't made the multiplexer yet). I guess I'll have to build some of my own touch sensors... I wonder why LEGO designed the touch (...) (25 years ago, 25-Aug-99, to lugnet.robotics)
  Re: multiplexed touch sensors [was: Re ideas for a RIS 2.0]
 
(...) Having revisited this entire sub-thread, it seems people started rambling on (constructively, I think) about switch times, debouncing, etc. Getting back to multiplexed touch sensors, I bet it's possible to get the Lego touch sensors to work (...) (25 years ago, 25-Aug-99, to lugnet.robotics)

Message is in Reply To:
  Re: ideas for a RIS 2.0
 
(...) If that were true, then the following multi-touch-sensor adapters would not work: (2 URLs) Robert Munafo (URL) LEGO: TC+++(8480) SW++ #+ S-- LS++ Hsp M+ A@ LM++ YB64m IC13 (25 years ago, 24-Aug-99, to lugnet.robotics)

22 Messages in This Thread:








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