MOTM

How about Human conductance?

Don't laugh... My daughter has a Ring Around the Rosie doll that has a metal
disk in the palm of each hand. When she holds each hand touching the disks
the circuit is completed and the doll sings Ring Around the Rosie. You can
even have several kids linked as long as they hold hands with bare skin or
metal and the doll will work... There's also those 'touch' lamps that used
to be popular, you know the ones that you would tap anywhere on the metal
body and the lamp would turn on or off... Then there's the Bang and Olufsen
stereo equipment from the late 70's early 80's that had all touch
controls...

I'm sure all these devices used some kind of low voltage that tripped a
relay when touched. I wonder though, could we use this concept for a ribbon
controller? So instead of trying to sandwich two contact materials that
spring back apart when released, you could you have 2 resistive strips
mounted side by side with a tiny gap between them. Then when you touch with
your finger you bridge the gap completing the circuit and as you ran your
finger up and down the 2 strips resistance would be increased or decreased?
Larry mentioned that "Nichrome wire may only have 50-100 ohms in a 3 foot
piece" so would having 2 resistive strips side by side would in theory
double the resistance wherever you had your finger completing the circuit?

Since I'm not an EE I'm not sure how these circuits work or how we could do
a ribbon without zapping ourselves using it. My small brain tells me that it
is possible and would be really cool!

Still thinking!
Al



-----Original Message-----
From: J. Larry Hendry [mailto:jlarryh@...]
Sent: Wednesday, March 27, 2002 8:21 AM
To: Alan Wagner
Subject: Re: [motm] List/Controller (Long but fun)

That might work OK.  I wonder how long it would hold up?  I've got once of
those around here somewhere.  "Oh, Honey, we need a new blind.  I don't know
what happened to this one." <g>
Thanks for the tips Al.


----- Original Message -----
From: Alan Wagner <aardvark-mi@...>
To: J. Larry Hendry <jlarryh@...>
Sent: Wednesday, March 27, 2002 5:42 AM
Subject: RE: [motm] List/Controller (Long but fun)


OK... Here's another one, you know those really cheap plastic window blinds
you get from Kmart? What about using the plastic slats? I just ran to all my
windows and unfortunately they are all metal and do not flex very well so I
couldn't check it out. Sounds possible. Mount your adhesive mesh to the
underside of the slat and then mount that on top of your resistive
element... And you can color coordinate with the d\ufffdcor in your home<g>!!!

Al

-----Original Message-----
From: J. Larry Hendry [mailto:jlarryh@...]
Sent: Wednesday, March 27, 2002 12:13 AM
To: Alan Wagner
Subject: Re: [motm] List/Controller (Long but fun)

Al, Thanks for the repsonse.  I have actally considered that.  But, I thingk
the downward pressure might be more than we want.  Don't want it to be too
hard to press and hold.  And, my real goal was that the ringer would
actually slide on the copper part.  Keep thinking.  I need help on this one.
The foam I mentioned is my best solution so far.
Larry


----- Original Message -----
From: Alan Wagner
Hmmm... This really odd but worth mentioning. I was at Home Depot yesterday
looking at rubber weather stripping. In particular there was one that slid
into an aluminum channel that had an upward curve along the entire length. I
wonder, if you were to use the adhesive side of you mesh to attach to the
bottom side of this weather stripping I bet it would have enough spring to
it that it would return back after pressing? You would then put your
resistive strip on (and insulated from) the aluminum channel. The one thing
that would concern me is would the material be too thick and too much
contact would made when pressed. Maybe worth checking into?
Just a thought!
Al