Hi Jim:
I have samples of two sizes of flipping dot displays, see:
http://www.prc68.com/I/LED.shtml#FD
was going to see how fast they can be flipped using high voltage drive
with a series resistor to lower the time constant, but other things got
in the way.
Have Fun,
Brooke Clarke
http://www.PRC68.com
Lux, Jim (337C) wrote:
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Hal Murray
Sent: Tuesday, February 16, 2010 4:25 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Hands on digital clock
It seems to me there is a way to make the segments folding so they
could be changed without removing and inserting boards. Kind of like
a folding ruler. I'll have to do some experiments with scraps of
wood in my shop. On a smaller scale of course.
Several years ago, I walked by one of the solar powered radar sets that shows
you your speed on a pair of big 7 segment displays. It was clicking as the
displayed speed changed so I stopped to look at it.
The segments rotate about the long axis.
So think of flipping the ruler segments over rather than folding them.
Those are very nifty displays. I can't recall when I first saw them, but it
has to have been back in the 80s or perhaps 70s.
The display element is magnetized, and they have a coil behind it that gets either a
positive or negative pulse to flip it. I seem to recall some sort of capacitor and SCR
circuit was used. They're nice because they don't consume any power when not changing,
and can be artificially illuminated as bright as you like. The "signaling" is
pretty robust, so you can put the display at the end of a long wire, too.
They aren't very fast, though. You couldn't display motion video.
But for a time nut? Sure. You could carefully balance them for aerodynamics,
and actuate them with floats and falling weights from your clepsydra, for
instance. Some sort of fluidic water level to 7 segment decoder would be
needed, but that could be very fun to design with buckets and counterweights
(e.g. you make a 3 input AND gate with a bucket that holds 3 liters of water,
counterweighted with a 2.5 kg weight)
Hmm, you sort of inherently get a thermometer code from a clepsydra, so you
need a thermometer to 7 segment decoder. I envision a giant jacquard loom or
piano roll scheme, with holes to fill or drain the weights that turn the
segments. Air pressure is also legal, I suppose.
It kind of depends on whether you need it to be totally gravity driven, or
whether a pump/compressor is ok.
(If you've ever seen the Villa d'Este in Tivoli, near Rome, you'd be amazed at
what can be done with air and water pressure, ALL gravity fed)
http://en.wikipedia.org/wiki/Villa_d%27Este (which is actually a pretty lame
description) google for "villa d'este organ fountain" and you'll turn up some
youtube video.
http://www.youtube.com/watch?v=gGJumf6m44M is one of them
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