To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.roboticsOpen lugnet.robotics in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 Robotics / 6547
6546  |  6548
Subject: 
RE: touch sensors aren't just switches (was Re: ideas for a RIS 2.0
Newsgroups: 
lugnet.robotics
Date: 
Wed, 25 Aug 1999 15:46:32 GMT
Original-From: 
Jim Thomas <Jim.Thomas@trw=stopspam=.com>
Viewed: 
581 times
  
You could always make a multiplexing circuit which does the thresholding and
debouncing for you.  Once the status of each switch has been turned into a
binary state you could then use resistors to create a sort of D/A which
works reliably -- just as you wanted.

JT

-----Original Message-----
From: Robert Munafo [mailto:munafo@NOgcctech.SPAMcom]
Sent: Tuesday, August 24, 1999 7:55 PM
To: lego-robotics@crynwr.com
Subject: Re: touch sensors aren't just switches (was Re: ideas for a RIS
2.0


In lugnet.robotics, lego-robotics@crynwr.com (Tilman Sporkert) writes:
Many "buttons" in today's electronic devices are designed that way. Check
your TV remote control, your key-chain remote control for your garage door
opener or car alarm, the buttons on your phone etc. It eliminates the need
for a physical switch. All you need is a pair of copper pads under each
button. These are just part of the normal circuit board that you need
anyway. The rest is a hole in the cover, a piece of plastic ("the button"),
a spring, and a small piece of conductive rubber.

I think it also removes the need to eliminate "keybounce", the annoying
thing
that happens with real switches due to dirt on the contact surfaces and tiny
arcs (sparks) just before initial contact.

Regardless, it seems to me that I'll do better making real switches. I was
planning on doing debouncing in software anyway (although I'd really rather
have gray coding in the multiplexer so I don't have to worry about that
either
:-)

Anyway, thanks for your responses and good explanations.

- Robert Munafo                           http://www.mrob.com/
  LEGO: TC+++(8480) SW++ #+ S-- LS++ Hsp M+ A@ LM++ YB64m IC13
--
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



Message has 1 Reply:
  RE: touch sensors aren't just switches (was Re: ideas for a RIS 2.0
 
(...) The debouncing isn't the real problem, it's the variable resistance as the switch is being pressed which alaises the touch sensor. By building a MUX circuit which does thresholding and debouncing you effectively make the system way more (...) (25 years ago, 25-Aug-99, to lugnet.robotics)

2 Messages in This Thread:

Entire Thread on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact
    
Active threads in Robotics

 
Verified and Trusted Team of Hackers
6 hours ago
Custom Search

©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR