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ka7ehk

Posted: Jan 26, 2012 - 06:31 PM

Joined: Nov 22, 2002
Posts: 12196
Location: Tangent, OR, USA

Hi Folks -

I am looking for a display with very large characters (at least 6" tall). This could be 7-segment or dot matrix. It could be single character per module or multiple characters. It could be LCD or any other low power technology; LEDs take waaay too much power for this application. System will be solar powered with a very small panel and it needs to be daylight readable.

There will be 3 such devices and each will need 3 characters, minimum. Cost is, of course, an issue, but there is flexibility. I'd have a hard time with $100US per device but could probably handle $25US. This is (initially) not a commercial project, so obscure, limited quantity, sources are tolerable.

Sources, suggestions, etc, are now being solicited.

Thanks
Jim

_________________
Jim Wagner
Oregon Research Electronics, Consulting Div.
Tangent, OR, USA

"The only thing standing between us and victory is defeat" P.G.Wodhouse in Wooster & Jeeves series

thavinator

Posted: Jan 26, 2012 - 06:43 PM

Joined: Jun 08, 2011
Posts: 314
Location: Maryland, USA

Would you consider an electromechanical display? Like what used to be used for those programmable construction signs, and transit buses and such. You should have no problem finding them large enough, and they might meet your power requirements if the display doesn't change too frequently.

clawson

Posted: Jan 26, 2012 - 06:44 PM

Joined: Jul 18, 2005
Posts: 62944
Location: (using avr-gcc in) Finchingfield, Essex, England

You are not the first to seek something like this Wink

http://www.avrfreaks.net/index.php?name ... highlight=

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ka7ehk

Posted: Jan 26, 2012 - 06:55 PM

Joined: Nov 22, 2002
Posts: 12196
Location: Tangent, OR, USA

Electromechanical would be just fine. They will change very infrequently to show height of flood water that could be over a road.

Right, I knew this had been a previous thread but could not find it.

Thanks
Jim

_________________
Jim Wagner
Oregon Research Electronics, Consulting Div.
Tangent, OR, USA

"The only thing standing between us and victory is defeat" P.G.Wodhouse in Wooster & Jeeves series

Kartman

Posted: Jan 27, 2012 - 05:59 AM

Joined: Dec 30, 2004
Posts: 9006
Location: Melbourne,Australia

Bodet make such devices. Each segment has two solenois- a set and reset. Only need to pulse 12V at around 200mA for 150ms to change state. I don't think they'll meet the budget constraints though.

peret

Posted: Jan 27, 2012 - 06:17 AM

Joined: May 26, 2004
Posts: 2538
Location: Las Vegas, Nevada

My god, Cliff - that's the console output from Deep Thought! Where ever did you find it?

jan_dc

Posted: Jan 27, 2012 - 07:49 AM

Joined: Feb 09, 2011
Posts: 335
Location: Turnhout, Belgium

What is the maximum power requirement and desired voltage and current?

I would suggest a graphical LCD display with 1 character per display turned 90 degrees. Or use multiple to create larger display. Or even one LCD display per segment (just on or off). But this will not meet the 25$ restriction.

An other suggestion is using a small (LED) display and use a magnifier lens. There are those flat lenses that can be make the display larger and visible from a wide range.

alank2

Posted: Jan 27, 2012 - 01:08 PM

Joined: Jul 16, 2009
Posts: 1587

Hi,

Sure electronics has a board like this, but they show 0 stock right now:

http://www.sureelectronics.net/goods.php?id=721

Futurlec also has something like this, but it isn't as pretty:

http://www.futurlec.com/Lg_LED_7_Segment.shtml

Good luck!

Alan

chartman

Posted: Jan 27, 2012 - 01:43 PM

Joined: May 01, 2003
Posts: 580

Why do respondants suggest LEDs when the OP already said they are way too power hungry ?

jan_dc

Posted: Jan 27, 2012 - 02:00 PM

Joined: Feb 09, 2011
Posts: 335
Location: Turnhout, Belgium

chartman wrote:

Why do respondants suggest LEDs when the OP already said they are way too power hungry ?

For 2 reasons: there are no power specifications given and it's impossible to find LCD based things of that size and that budget.

alank2

Posted: Jan 27, 2012 - 03:02 PM

Joined: Jul 16, 2009
Posts: 1587

Hi,

chartman wrote:

Why do respondants suggest LEDs when the OP already said they are way too power hungry ?

I missed the low power part - when he was asking for large displays these just popped into my mind. I've never seen a LCD that big, I would think some type of mechanical may be the only low power option and I'm not sure how low power they could be.

Thanks,

Alan

Brutte

Posted: Jan 27, 2012 - 04:04 PM

Joined: Oct 05, 2006
Posts: 2297
Location: Poland

Perhaps this thing could help:

http://www.alibaba.com/product-gs/44758 ... elmet.html

It is closer to the budget than any other proposition, although some tweaks are needed. 6" is 152mm and these can be used as 93mmx43mm segments which will give about 200mm display. I do not think modifying those from transmissive to reflective is a problem. And the design is weatherproof (no moving parts).

Perhaps someone knows abut individual 7-segment segments sold separately that fit nicely?

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No RSTDISBL, no fun!

clawson

Posted: Jan 27, 2012 - 06:20 PM

Joined: Jul 18, 2005
Posts: 62944
Location: (using avr-gcc in) Finchingfield, Essex, England

Quote:

For 2 reasons: there are no power specifications given and it's impossible to find LCD based things of that size and that budget.

Do you understand the word "irony" ? Laughing

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peret

Posted: Jan 27, 2012 - 06:29 PM

Joined: May 26, 2004
Posts: 2538
Location: Las Vegas, Nevada

clawson wrote:

Do you understand the word "irony" ? Laughing

Please sir! Please sir! Pick me!

The picture you posted was irony. Alan2k's link was plasticky, and Brutte's was glassy.

Do I get an A?

gdhospers

Posted: Jan 27, 2012 - 06:56 PM

Joined: Oct 04, 2008
Posts: 413

If it is for water on a road, you could use a scale and move an indicator (with rope+motor) electrically.

Or build this in king size

Or paint your number wheel and rotate with stepper.

Smoke signal display

Casino's show all kinds of number displays...
This you could make at a skippy ball size

Or modify a praying mill (hope it is n't blasphemy)

In the mean time listen to thishttp://www.youtube.com/watch?v=r364h19dXio

Searching for "Uhren" "Kunst" brings this crazy stuff:

A real techie idea:
http://www.hadro.nl/Engels/default.htm

mikech

Posted: Jan 27, 2012 - 11:38 PM

Joined: Aug 19, 2003
Posts: 404
Location: Australia

Something esoteric could be e-paper. (ala Kindle)

Downsides are ;
50'C limit,
needs front-lighting at night,
needs UV protection,
custom production,

Upsides are ;
daylight readable,
very low power consumption,
almost any shape/size/resolution you want,
bendable,

ka7ehk

Posted: Jan 28, 2012 - 02:30 AM

Joined: Nov 22, 2002
Posts: 12196
Location: Tangent, OR, USA

I really like the moving vane indicators. Its rough finding any. I've found LCD digits at 75mm tall for around $15US (per digit) - that makes it tough but possible.

Thanks for the "innovative" suggestions.

Does anyone know of a source for little motors that would run from something in the 4-6V range? Little motors could swing big vanes (out of the weather). Thinking, here, of "home-made" vanes. One motor per vane instead of two solenoids. Again, "surplus" is acceptable.

<edit>Just did some searching. Lots of little motors out there, but most are pretty high speed: 5000RPM and up. They are available in modest quantities for around $1.00US. Need to do some thought-designs, now, to see what will work.</edit>

My reason for low power is that this thing has to be fully self contained, maybe with a small solar "panel". Displaying water level means that things do not change very often, But, LEDs, on continuously, for night viewing, would be a killer. At night, it would have to be illuminated by vehicle headlights and visible from maybe 10'.

Again, thanks for the ideas!

Jim

_________________
Jim Wagner
Oregon Research Electronics, Consulting Div.
Tangent, OR, USA

"The only thing standing between us and victory is defeat" P.G.Wodhouse in Wooster & Jeeves series

Xantor

Posted: Jan 28, 2012 - 04:49 AM

Joined: Aug 19, 2008
Posts: 153

Try these:

http://www.flipdots.com/

Chuck-Rowst

Posted: Jan 28, 2012 - 10:53 AM

Joined: Jul 19, 2011
Posts: 478

Jim,

Depending on project budget and production volumes, you might consider a custom single-digit 7 segment twisted-nematic LCD display. There are a number of companies here in the USA that will make small qty's with a reasonable set-up and production cost. I have had custom displays made in the past, but not recently. The design process is very similar to that for a single-layer PC board. You submit the artwork of the segments and interconnects and they do the rest.

gdhospers

Posted: Jan 28, 2012 - 12:01 PM

Joined: Oct 04, 2008
Posts: 413

Chuck-Rowst wrote:

Will they do that for Jim's budget of
$100?

I think he intends to provide free labour and what is available in his barn. To me it seems the only way to realize such a project at such a budget.

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