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Smallest LCD/LED-module character/dot display ???

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watchjohn

watchjohn

Electrical
Mar 28, 2007
27
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Hi,

For my wristwatch sized bugdetector
i need a very small display(module)...it should be:

a) Small as possible something like 20 mm x 10 mm x 3 mm

b) 4 characters (alphanumeric or even better dotmatrix)

c) Low voltage 5 V or better less

d) Low power draw 100mA or better much less

e) LCD or LED technique

f) Interface methods can be serial/i2C/parallel/any other

Examples of what it should display (one at the time)

VOL4
SQL8
BND3
MENU
1256

Battery power available 2.4 V/3 V (2x Nimh/Nlkaline)
If higher voltage required a DC/DC converter could be used
but should be inductor/RF-less since that might cause
interference in the receiver

Display should be a current model
Available from stock...NOT custom
Preferably more then only 1 supplier
Price max 40 Euro´s

I have done very extensive internet searches
what i found might work but each of them has it´s own
problems:


a)

Siemens/Osram/HP/Avago
SLR2016/SLO2016/SLG2016/SLY2016


Not bad...but slightly to big (hight)
Needs 5 V /110 mA (a litle to high/much)
Don´t like the (to much)separation between digits
Price OK.



b)
Osram ISD-series...same as Avago/HP (LED dotmatrix)


Almost same as a) but less higher

Very nice...but very expensive and nowhere in stock.



c) PacificDisplays 4101 (LCD serial I2C)


Almost !
...just it does only seven segment numbers
NOT alphanumeric characters.
I like to have real charactars not ugly characters
made-up from 7 digit numerical displays.

Power supply can be 2 to 6 volts at less then 200 uA !
I2C interface is perfect !

Needs a backlight diffuser ( adds 3 mm )
so total thickness a little to much again

Biggest problem...NOT Alphanumeric
Only 1 supplier in the world.


--------
Resuming
--------


Anyone knows of a display (module) that suits my needs ?


Thanks !

WatchJohn
 
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Thanks Keith,

Checked out both companies...they have NO off-the-shelf
4 digit, alphanumeric or dotmatrix display
...that comes close to mentioned small size
...maybe i have overlooked it ?

LED would be fine... i wouldn´t care..they could be
better readable in the light)no backlight needed)
i could PWM them to save power
Mentioned OSRAM and AVAGO displays are not
that bad for my purpose...just either a little to big or
a little to expensive..they are almost right.

Right now i´m now checking on (dotmatrix) LCD-displays used in cellphones...have not find a good one yet...to big
i just need 4 alphanumeric digits.


Thanks !


WatchJohn
 
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I highly doubt you'll find what you need off-the-shelf. It won't be OTS, but if this were my project I'd look into e-paper style displays... they take longer to write to, but power draw is zero after you've written to it (yes, actually zero), and it will give you a dot matrix style.

Depending upon type, some LCDs (reflective) show awesome contrast in bright lights, no backlight required (or possible). LEDs are going to be more power-hungry than LCD.

Dan - Owner
Footwell%20Animation%20Tiny.gif
 
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Hiya-

Ran across this site:


They have some 1.5" color TFT LCD display modules which may or may not be of interest to you. I think that works out
to 40mm or so.

Still, it's a small display. Pretty good resolution. You might be able to enhance the user experience with this display. Some of the functionality/useablility of this can be transfered to the display? Something like the bank atms where a "soft" menu and a row of keys? UP/DOWN SELECT

Basically, for me, it's just something to "tuck away" for a future project if required. The little module with the six pushbuttons and micro is interesting to me. No real plans for it.

I am not affiliated with the company, site, or much of anything.

Cheers,

Rich S.
 
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Those are some pretty nice prices indeed.

At the last Embedded Systems show I went to a company that was selling small graphical displays that were also an outstanding price. They were handing out samples even. I said thanks but one sample can be a problem if you mess it up and suddenly have to find another so they handed me 5 in a box!!

EarthLCD.com

Keith Cress
Flamin Systems, Inc.-
 
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Yes, Rich.

That is exactly what I have been looking for for some time. I Talked to Peter Kuester over the phone. He speaks excellent English - if your German isn't quite what it used to be. There will be 3.1" touch screens available at the end of summer.

Gunnar Englund
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Hi guys-

Glad to hear that there is interest in these types of displays. I'll be interested in hearing feedback from the group concerning these.

As mentioned, I'm not planning on one right away, but the thought of a touch screen one is exciting! Opens up all sorts of possiblities.

Me, well I've bookmarked Earthlcd.com myself. Looks like a great resource!

Cheers,

Rich S.
 
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.

Thanks,


The displays in the Digikey catalog are either to big
or they are not alphanumeric...also i have a problem understanding exactly what the sizes of the modules are
as far as i can see now...nothing for me unless i´m overlooking something.

The displays from that German company (Display3000)
might be an interesting ...indeed i could use softkeys to easely change the functions by a software change only.

Check out below Australian company they have something similar ...the have LCD but also OLED one of them is
even smaller...there seems to be a burn-in problem with OLED´s...on the other hand they dont need high voltages
and backlighting is not needed.

These Australian displays also come with a small PCB mounted
on the back...these have no usable uP onboard but can be simple controlled via RS232 from a uP like PIC
These also have onbard FLASH memory up to 8 Mb
to store text,icons,pics and even short video´s

Oled demo-video(4Dsystems):
-----------

(the video-interference is not there in real life)


Manufacturer of this display and some sellers:
----------------------------------------------



Finally if i would use that for my wristwatch-sized
bugdetector it will look something like this:

MP4 Player (wristwatch video player using OLED)
----------------------------------------------




Video demos of OLED based wristwatch MP4 players
(a whole load):




Problems still to solve
-----------------------

A)

If i would use such OLED or LCD display wich will
cover the whole surface of the faceplate of my detector
i will have no more room for my speaker...wich is the smallest available speaker as used in cellphones with
build-in mp3 players.
it´s size is about 15mm round 4mm high.
I want good audio (100mW at least)

B)

These displays are connected to a microprocessor
wich need a clockgenerator running at somewhere between
1 and 8 Mhz...i might have a problem,
My detector is made to receive anything between
0.1 Mhz up to 10 Ghz...so it might very well pick-up
radiation from that clockfrequency itself,since the antenna
is on the watchsized-detector itself it will be no more
the 10 mm away from the uP !
In the best case i can screen it and use good filtering
on the power-lines.
In the best case it will only increase the received noisefloor...wich will effectively make my unit less sensitive for weak(er)signals.

C)

Again the battery...using such display i will probably have no more room for only 1 (rechargable) battery of the size AAA wich is 10,5 mm round , 44,5 mm long.


My unit will consume an average 100 mA (peaks 200 mA)
i will have to switch-off the display when not needed
I like it to run at least 10 hours.

I prefer NimH battery wich is 1.2 Volt
I will need a voltage converter capable of
coverting 1.2 V into 5 V @200 mA (peak)
A high effiency converter is needed (at least 88%)

I don´t like a converter that needs an (big)inductor
since these also cause fields (radiation)
at 400 khz to 1.5 mhz

Inductor-less converters
can´t deliver more then 100mA (switch capacitor types)
or they can´t start from as low as 1,2 Volts



Thanks again...more ideas welcome (and needed)


WatchJohn
 
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.

Hi itsmoked,

> "a second to update"

I dont know about that
...how can they play smooth video then?
...that is at least between 10 to 30 frames per second !!

Maybe you have seen a demo where someone tried to show
a 3D model that was moving...and it maybe was slow
because the model was actually calculated by an
attached (external) microprocessor..so that slow was
probably caused by the (slow) uP and not the display ?


is that slow ?
it´s faster then the eye ! (actually your brain)

(don´t mind the flickering wich is not there in real life
you see that because of the difference in framerates
of the OLED-display and the videocamera that recorded it)

Here´s the one again that i maybe want to use:


If you watch carefull it´s fast enough so i assume
if you´ve seen anything "Slow" that that was caused
by the source not the display.


To convince you...here´s big screen TV´s using OLED
that could not be if they would be "to slow"
...within 1 year on the market:



Here´s another video i found...they are euphoric
but it seems that OLED´s are not yet fully developed
specially they seem to get "old" to soon...still they
are used in many products already.



Let me know if i´m wrong ?

WatchJohn
 
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.


OK no problemo...thanks !

One thing with OLED´s is that it takes a second
to switch them on...meaning...if it´s off because
you want to save power...it will take a second
to get a picture,so you could miss some information,
that could be overcome by storing/buffering whatever info
there was during that first second...or leave the display on

Those Ch-leds (Bistable Cholerestic Displays )
are very interesting...i understand that once information
is written to the display they don´t need any power
anymore while the information is still displayed.
absolutely ZERO power needed !

That would be great...as you said they need time to
get updated maybe that is 1 second...so not good for
dynamic displays..such as my application (fast field strength indication).
Every thing else seems to be perfect for me...since:

Very low power consumation.
Probably no inverter needed.
No RF-emissions.
No backlight needed.
Very thin.
...etc

I have tried to find info on the highest possible
refresh rate (less then a second ?) but i could´nt find
it...since the manufacturers don´t (like to)mention it.

Any idea where to find that info ?
(not available at Kentdisplays)

I would be happy with such Cholesteric-Display
that can do about 10 frames/sec
Display size (active area) about 40 x 30 mm or less
best with an onboard processor (COG) with serial interface.

Here´s something that looks fine:


So i found the manufacturer:


But they don´t even mention it and their English sucks


Thanks !

WatchJohn
 
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I think you mean ChLCDs, not ChLEDs, Keith. I agree that this is going to be the lowest power (can't get lower than 0 current for an unchanging display) solution. I think this is the same thing that Macgyvers2000 mentioned earlier.

John, I doubt that any LED solution (OLEDs and otherwise) will hit your power requirements. And, although I can't seem to find any power requirements on the Display3000 site, it looks like they require backlights, which will blow your power budget. (Pretty cool stuff though. I've bookmarked it for later)
 
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Re Display 3000,

My (future) project also needs a low power display. Those shown consume 50 - 60 mA. That's a lot better than the typical 200 mA that I have seen on other displays. But still about ten times what I can accept.

They are transflexive. That means that they can be read without backlight. If the ambient light is high. You need the backlighting in dark places.

I have been looking at OLEDS and PLEDS. Power consumption is not a problem - only a few mA. But life seems to be short. Hope that will change before I get my act together and need them.

Gunnar Englund
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Prices look good. But, they have also discontinued the PLED/OLED displays. I need something with low power consumption for a hand-held device.

I am actually thinking of an analogue panel meter. Now, wouldn't that be retro? The micro feeds the meter via a PWM output. Besides indicating measured values (I do not need high accuracy), I can let the meter do things like saying "YES" and "NO". It can also indicate storage address (1 - 20) and such. No, I am not joking. That would give me most of the functionality I need. A few LEDs to indicate measuring range makes the whole thing complete.

A white scale and a wide black needle can be seen in most places where it is light enough to do any work.

Sorry to have high-jacked this thread. Won't do it again...

Gunnar Englund
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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