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| _... |
 Posted: Sun Nov 01, 2009 10:47 am |
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Guest
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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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| whit3rd... |
| Posted: Sun Nov 01, 2009 10:47 am |
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Guest
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On Nov 1, 7:47 am, _ <jtayNOSPAM... at (no spam) hfDONTSENDMESPAMx.andara.com>
wrote:
[quote]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,
[/quote]
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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| Jamie... |
| Posted: Sun Nov 01, 2009 11:53 am |
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Guest
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_ wrote:
[quote]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.[/quote]
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... |
| Posted: Sun Nov 01, 2009 1:13 pm |
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Guest
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On a sunny day (Sun, 01 Nov 2009 11:53:51 -0500) it happened Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_ at (no spam) charter.net> wrote in
<BPiHm.14244$l67.3316 at (no spam) newsfe03.iad>:
[quote]Of course, with today's technology, this project is being done in
Windows using delphi as the front end.
[/quote]
Of course?
[quote]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
[/quote]
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?
[quote]
Have a good day..
[/quote]
Just beware of that blue windows screen.
hehe
[quote]
[/quote] |
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| Mike Williams... |
| Posted: Sun Nov 01, 2009 9:08 pm |
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Guest
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On Sun, 01 Nov 2009 15:47:20 +0000, _ wrote:
[quote]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).
[/quote]
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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| Jan Panteltje... |
| Posted: Mon Nov 02, 2009 5:22 am |
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Guest
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On Nov 1, 4:47 pm, _ <jtayNOSPAM... at (no spam) hfDONTSENDMESPAMx.andara.com>
wrote:
[quote]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).
[/quote]
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... |
| Posted: Mon Nov 02, 2009 5:39 am |
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Guest
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On 2 Nov., 16:22, Jan Panteltje <pantel... at (no spam) gmail.com> wrote:
[quote]On Nov 1, 4:47 pm, _ <jtayNOSPAM... at (no spam) 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.
[/quote]
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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| David Eather... |
| Posted: Mon Nov 02, 2009 10:00 am |
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Guest
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_ wrote:
[quote]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).
[/quote]
This probably has the info you need on power vs speed.
http://ww1.microchip.com/downloads/en/AppNotes/91098A.pdf |
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| Adrian C... |
| Posted: Mon Nov 02, 2009 10:56 am |
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Guest
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_ wrote:
[quote]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).
[/quote]
Probably better transmitting data using the LCD backlight.
--
Adrian C |
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| Jan Panteltje... |
| Posted: Mon Nov 02, 2009 11:28 am |
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Guest
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On a sunny day (Mon, 2 Nov 2009 07:39:31 -0800 (PST)) it happened
untergangsprophet <filter001 at (no spam) desinformation.de> wrote in
<ef8c15c7-57e3-4f0d-94ac-a5441f7f95e5 at (no spam) p35g2000yqh.googlegroups.com>:
[quote]On 2 Nov., 16:22, Jan Panteltje <pantel... at (no spam) gmail.com> wrote:
On Nov 1, 4:47 pm, _ <jtayNOSPAM... at (no spam) 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 m=
ode
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.
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
[/quote]
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... |
| Posted: Mon Nov 02, 2009 11:29 am |
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Guest
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On a sunny day (Mon, 02 Nov 2009 15:56:53 +0000) it happened Adrian C
<email at (no spam) here.invalid> wrote in <7l8dqaF3ct641U2 at (no spam) mid.individual.net>:
[quote]_ 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.
[/quote]
Very clever!
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| oopere... |
| Posted: Wed Nov 04, 2009 4:10 am |
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Guest
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Adrian C wrote:
[quote]_ 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.
[/quote]
A very nice idea indeed!! |
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