Tony,

You could reduce the current consumption by multiplexing the dots within
each digit, and
Multiplexing each digit.   Or you could have each digit on all the time
and just multiplex 
Dots within each digit.  That would effectively be the same as 4 LED's.
Ie 4 Led's at @20ma 
would be less than .1A.  Much more acceptable.

 
Regards,

	
Jim  

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Tony Smith
Sent: Wednesday, May 23, 2007 10:43 AM
To: 'Microcontroller discussion list - Public.'
Subject: RE: [EE]: Digital voltmeter from 1960

> >> >A real gem. Pity there is no schematic available:
> >> >
> >> >  http://www.wps.com/projects/instruments/Cubic-V45/index.html
> >> >
> >> >Peter P.
> >> >
> >> Fascinating instrument, a real gem as you say.  I'm not
> sure I agree
> >> with the authors suggestion that "Display technology has improved 
> >> only slightly" though!
> >> 
> >> Regards
> >> 
> >> Mike
> >
> >
> >What to do when Nixies haven't been invented yet.  Years ago I came 
> >across Nixies, and figured I could emulate the display by,
> you guessed
> >it, etching numbers in glass, edge lit & stacked.  Worked
> nicely as a
> >clock, and I was suitably chuffed at my technical progress.
> >
> >I was less chuffed when I discovered voltmeters like this, and even 
> >less when I found out the Russians did it 30 or so years before that.
> >
> >I've been meaning to make a 7 seg version, you only need 7 pieces of 
> >glass/plastic per digit then.
> >
> >Tony
> 
> If you had enough sheets you could even make a dot matrix display :-)
> 
> Mike


That thought had not occurred to me.  Probably a good thing.

Hmmm.

7 thin strips, a dot on each, being one vertical line.  5 strips for a
typical display, so 35 pieces.  A clock needs at least 4 displays, so
that's
4 x 5 x 7, or 140 pieces.  With LEDs @ 20mA, that's pushing 3 amps.

It's hard to cut thin strips of glass, 5mm should be ok.  Assembled
would be
35 x 25mm per 'number'.

Bi-colour can be done by having a LED at each end of the glass strip
(window glass is 3mm, for pictures it's 2mm).  Gosh, where would I find
a 2 x 5mm LED?

I'll add it to the pile.  Don't expect much progress  :)

Tony

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