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Speed and cost of switching LCD segment
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_  
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 More options Nov 2, 2:47 am
Newsgroups: sci.electronics.design
From: _ <jtayNOSPAM...@hfDONTSENDMESPAMx.andara.com>
Date: Sun, 01 Nov 2009 15:47:20 GMT
Local: Mon, Nov 2 2009 2:47 am
Subject: Speed and cost of switching LCD segment
I have an idea - sort of a reverse of the timex datawatch transmission
sytem.

It's to have a sort of cradle into which a stopwatch is placed, and a mode
where the watch transmits its stored info by rapidly switching some of the
LCD segments, which are read by the cradle.

How fast can you switch an LCD segment, and would power used versus speed
be an important trade-off (watch power is usually some smallish lithium
cell; the cradle power isn't a factor).


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Jamie  
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 More options Nov 2, 3:53 am
Newsgroups: sci.electronics.design
From: Jamie <jamie_ka1lpa_not_valid_after_ka1l...@charter.net>
Date: Sun, 01 Nov 2009 11:53:51 -0500
Local: Mon, Nov 2 2009 3:53 am
Subject: Re: Speed and cost of switching LCD segment

_ wrote:
> I have an idea - sort of a reverse of the timex datawatch transmission
> sytem.

> It's to have a sort of cradle into which a stopwatch is placed, and a mode
> where the watch transmits its stored info by rapidly switching some of the
> LCD segments, which are read by the cradle.

> How fast can you switch an LCD segment, and would power used versus speed
> be an important trade-off (watch power is usually some smallish lithium
> cell; the cradle power isn't a factor).

LCD is slow.

  Which kind of hits on a project I'm currently developing at work.

  Using a video recognition system to look through an object of
  rotating wires being cabled with a silicone grease dispenser high
pressure pump that files the cavity in the center.

   Using optical targeting systems work 75%, but we're trying for a
100% target acquisition to determine, if, the high pressure pump system
  needs to replenish the silicone as it's being consumed by the
  water blocked cabled product that is being grouped, with out waste.

   You can imagine the cost of materials and profit margin which
drives to development of these devices.

   It's been 25 years since I've gotten into a project like this, the
last time I used camera's in this fashion was with a Z80 computer based
system using a B&W camera with high res to perform a line inspection of
  those large squeeze bottles of the "Hershey Chocolate" bottles to
determine if the label was correctly applied on the bottle and reject
it, if not. Because the bottle and Label are both the same color and the
only variations were the image of data on the label itself, in Silver,
made for a tricky out come. But it was successful. And this was done
  in the computer language "FORTH".

  Of course, with today's technology, this project is being done in
Windows using delphi as the front end. All is coming along just fine.
  We're planing on using a mini Windows XP panel screen to operate this
when completed.

   So, if you are a computer jock, I guess you could use a LCD web cam
to look at the watch and then acquire your information! :) OCR

Have a good day..


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Jan Panteltje  
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 More options Nov 2, 5:13 am
Newsgroups: sci.electronics.design
From: Jan Panteltje <pNaonStpealm...@yahoo.com>
Date: Sun, 01 Nov 2009 18:13:47 GMT
Local: Mon, Nov 2 2009 5:13 am
Subject: Re: Speed and cost of switching LCD segment
On a sunny day (Sun, 01 Nov 2009 11:53:51 -0500) it happened Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote in
<BPiHm.14244$l67.3...@newsfe03.iad>:

>  Of course, with today's technology, this project is being done in
>Windows using delphi as the front end.

Of course?

> All is coming along just fine.
>  We're planing on using a mini Windows XP panel screen to operate this
>when completed.

>   So, if you are a computer jock, I guess you could use a LCD web cam
>to look at the watch and then acquire your information! :) OCR

LCD webcam? Most webcams are CMOS, you must have ment CCD.

My digital watch changes segments so slow that you would get less then a 1 Baud bitrate.
OK, with seven segments 7 Baud?

>Have a good day..

Just beware of that blue windows screen.
hehe


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whit3rd  
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 More options Nov 2, 5:57 am
Newsgroups: sci.electronics.design
From: whit3rd <whit...@gmail.com>
Date: Sun, 1 Nov 2009 10:57:17 -0800 (PST)
Local: Mon, Nov 2 2009 5:57 am
Subject: Re: Speed and cost of switching LCD segment
On Nov 1, 7:47 am, _ <jtayNOSPAM...@hfDONTSENDMESPAMx.andara.com>
wrote:

> I have an idea - sort of a reverse of the timex datawatch transmission
> sytem.

> It's to have a sort of cradle into which a stopwatch is placed, and a mode
> where the watch transmits its stored info by rapidly switching some of the
> LCD segments, which are read by the cradle.

> How fast can you switch an LCD segment,

The kinds of LCD used in battery powered watches are slow, gonna
take a tenth of a second or so.  Other types of modulator are faster
(even moving-mirrors, but especially quantum dots...) but aren't
ready for low-cost consumer items.

It's possible to parallel a few dozen segments, of course; a tenth
second for a 32-bit parallel port, readout by a low-resolution
camera...

Didn't the Timex gizmos use a photovoltaic cell?  You can power an LED
with
a cradle that beams light into a PV cell... and maybe use IRDA
protocols.


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Mike Williams  
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 More options Nov 2, 1:08 pm
Newsgroups: sci.electronics.design
From: Mike Williams <use...@vfx.org.uk>
Date: Sun, 01 Nov 2009 20:08:42 -0600
Local: Mon, Nov 2 2009 1:08 pm
Subject: Re: Speed and cost of switching LCD segment

On Sun, 01 Nov 2009 15:47:20 +0000, _ wrote:
> I have an idea - sort of a reverse of the timex datawatch transmission
> sytem.

> It's to have a sort of cradle into which a stopwatch is placed, and a
> mode where the watch transmits its stored info by rapidly switching some
> of the LCD segments, which are read by the cradle.

> How fast can you switch an LCD segment, and would power used versus
> speed be an important trade-off (watch power is usually some smallish
> lithium cell; the cradle power isn't a factor).

Can the watch draw power from the cradle? Maybe via a pair of contacts,
or perhaps some inductive transfer scheme. If so, it doesn't have to
rely in the little lithium cell, and watch power isn't a factor either.

Mike


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David Eather  
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 More options Nov 3, 2:00 am
Newsgroups: sci.electronics.design
From: David Eather <eat...@tpg.com.au>
Date: Tue, 03 Nov 2009 01:00:46 +1000
Local: Tues, Nov 3 2009 2:00 am
Subject: Re: Speed and cost of switching LCD segment

_ wrote:
> I have an idea - sort of a reverse of the timex datawatch transmission
> sytem.

> It's to have a sort of cradle into which a stopwatch is placed, and a mode
> where the watch transmits its stored info by rapidly switching some of the
> LCD segments, which are read by the cradle.

> How fast can you switch an LCD segment, and would power used versus speed
> be an important trade-off (watch power is usually some smallish lithium
> cell; the cradle power isn't a factor).

This probably has the info you need on power vs speed.

http://ww1.microchip.com/downloads/en/AppNotes/91098A.pdf


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Jan Panteltje  
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 More options Nov 3, 2:22 am
Newsgroups: sci.electronics.design
From: Jan Panteltje <pantel...@gmail.com>
Date: Mon, 2 Nov 2009 07:22:44 -0800 (PST)
Local: Tues, Nov 3 2009 2:22 am
Subject: Re: Speed and cost of switching LCD segment
On Nov 1, 4:47 pm, _ <jtayNOSPAM...@hfDONTSENDMESPAMx.andara.com>
wrote:

> I have an idea - sort of a reverse of the timex datawatch transmission
> sytem.

> It's to have a sort of cradle into which a stopwatch is placed, and a mode
> where the watch transmits its stored info by rapidly switching some of theLCDsegments, which are read by the cradle.

> How fast can you switch anLCDsegment, and would power used versus speed
> be an important trade-off (watch power is usually some smallish lithium
> cell; the cradle power isn't a factor).

There is a second limiting issue,
if you want to use some CMOS camera to read the data,
and if it does say 30 fps, then Niquist tells you you
cannot flip segments faster then 15 x per second else you get
aliasing.

Say you have 4 digits, seven segments each, that makes 28 segments,
at 15 changes per segment per second, makes 420 bits / second max,
you need to be a bit lower, so say 300 Bd is the maximum you can ever
do that way..
You could use photo transistors with lenses looking at each segment to
up speed,
but that would be really complicated mechanicaly.
But I think it is a fun idea.
Maybe a faster CMOS sensor? Those do exist.


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untergangsprophet  
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 More options Nov 3, 2:39 am
Newsgroups: sci.electronics.design
From: untergangsprophet <filter...@desinformation.de>
Date: Mon, 2 Nov 2009 07:39:31 -0800 (PST)
Local: Tues, Nov 3 2009 2:39 am
Subject: Re: Speed and cost of switching LCD segment
On 2 Nov., 16:22, Jan Panteltje <pantel...@gmail.com> wrote:

But Claude Shannon said there's more to achieve.

Let's Say you could use a Bandwidth of 10Hz per Segment (mainly
limited by the LC Material). Each Segment should give a S/N of 100Db
at this low rate.
This means roughly 150 Bits/s/segment = 150*28 = 4200 Bits/s


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Adrian C  
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 More options Nov 3, 2:56 am
Newsgroups: sci.electronics.design
From: Adrian C <em...@here.invalid>
Date: Mon, 02 Nov 2009 15:56:53 +0000
Local: Tues, Nov 3 2009 2:56 am
Subject: Re: Speed and cost of switching LCD segment

_ wrote:
> How fast can you switch an LCD segment, and would power used versus speed
> be an important trade-off (watch power is usually some smallish lithium
> cell; the cradle power isn't a factor).

Probably better transmitting data using the LCD backlight.

--
Adrian C


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Jan Panteltje  
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 More options Nov 3, 3:28 am
Newsgroups: sci.electronics.design
From: Jan Panteltje <pNaonStpealm...@yahoo.com>
Date: Mon, 02 Nov 2009 16:28:29 GMT
Local: Tues, Nov 3 2009 3:28 am
Subject: Re: Speed and cost of switching LCD segment
On a sunny day (Mon, 2 Nov 2009 07:39:31 -0800 (PST)) it happened
untergangsprophet <filter...@desinformation.de> wrote in
<ef8c15c7-57e3-4f0d-94ac-a5441f7f9...@p35g2000yqh.googlegroups.com>:

That is true,
parly switching a segmant would give more values then a 0/1 value.
But I am not sure how 'analog' you can drive a watch segment.

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Jan Panteltje  
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 More options Nov 3, 3:29 am
Newsgroups: sci.electronics.design
From: Jan Panteltje <pNaonStpealm...@yahoo.com>
Date: Mon, 02 Nov 2009 16:29:05 GMT
Local: Tues, Nov 3 2009 3:29 am
Subject: Re: Speed and cost of switching LCD segment
On a sunny day (Mon, 02 Nov 2009 15:56:53 +0000) it happened Adrian C
<em...@here.invalid> wrote in <7l8dqaF3ct64...@mid.individual.net>:

>_ wrote:
>> How fast can you switch an LCD segment, and would power used versus speed
>> be an important trade-off (watch power is usually some smallish lithium
>> cell; the cradle power isn't a factor).

>Probably better transmitting data using the LCD backlight.

Very clever!
:-)

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oopere  
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 More options Nov 4, 8:10 pm
Newsgroups: sci.electronics.design
From: oopere <m...@somewhere.net>
Date: Wed, 04 Nov 2009 10:10:53 +0100
Local: Wed, Nov 4 2009 8:10 pm
Subject: Re: Speed and cost of switching LCD segment

Adrian C wrote:
> _ wrote:
>> How fast can you switch an LCD segment, and would power used versus
>> speed be an important trade-off (watch power is usually some smallish
>> lithium cell; the cradle power isn't a factor).

> Probably better transmitting data using the LCD backlight.

A very nice idea indeed!!

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