Post by thread:[EE] Cute little 4-digit display...

In message <spam_OUT97e2d12b8fe6e63d106d3b51a9b1248eTakeThisOuTmac.com>> William "Chops" Westfield <.....westfwKILLspam@spam@mac.com> wrote: > http://store.hexsys.biz/cubecart/index.php?act=viewProd&productId=11 Now that's nice.. But what I really want is the same sort of thing with eight digits.. I have yet to find a commercially-available 8-digit LCD that's less than half an inch tall. Well, aside from calculator LCDs, but they're a pain in the neck to reverse engineer :-/ Later. -- Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT philpemKILLspamphilpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook ... 2400 Baud makes you want to get out and push!!

>Speaking of calculator displays, does anyone know of a source >for the flexible contact strips wsed between board & glass? Known as "elastomeric connector" >Preferably European, but beggars can't be choosers. I really >don't want to go breaking calculators to get them. Hmm, I thought this might tell you http://www.densitron.com/editor/pdfs/front_panel_apps.pdf but it looks like it doesn't give suppliers, but does give info on push button construction with flexible front panels ;)) But this one looks more helpful http://www.eecoswitch.co.uk/connectors.html Maybe this one http://www.twp-europe.co.uk/pages/conn.html Didn't find anything on RS or Farnell.

> -----Original Message----- > From: .....piclist-bouncesKILLspam.....mit.edu [EraseMEpiclist-bouncesspam_OUTTakeThisOuTmit.edu]On Behalf > Of Joe McCauley > > Speaking of calculator displays, does anyone know of a source for the > flexible contact strips wsed between board & glass? Preferably > European, but I think you are looking for "Elastomeric Connectors" - google and see if you get anywhere... http://www.zaxisconnector.com is the first one that pops up for me :) but they are in the USA. -- Mark

look for zebra strips Larry > > From: "Joe McCauley" <joe.mccauleyspam_OUTtcd.ie> > Date: 2005/12/07 Wed AM 10:23:45 EST > To: "'Microcontroller discussion list - Public.'" <@spam@piclistKILLspammit.edu> > Subject: RE: [EE] Cute little 4-digit display... > > Speaking of calculator displays, does anyone know of a source for the > flexible contact strips wsed between board & glass? Preferably European, but > beggars can't be choosers. I really don't want to go breaking calculators to > get them. > > Thanks > > Joe > > > {Original Message removed}

>> http://store.hexsys.biz/cubecart/index.php?act=viewProd&productId=11 > > Now that's nice.. But what I really want is the same sort of thing with > eight > digits.. I have yet to find a commercially-available 8-digit LCD that's > less > than half an inch tall. Well, aside from calculator LCDs, but they're a > pain > in the neck to reverse engineer :-/ > > Later. > -- > Phil. | Acorn RiscPC600 SA220 64MB+6GB > 100baseT Well, if you need enough of them get Pacific to make them for you. I wonder how expensive it would be? Assumptions: Use same chip, digit size and construction technique as the 4-digit guy. Add decimal points (with eight digits you're more likely to need them) The only issue I see with keeping it under 1/2" tall is that it might be difficult to route all the traces between the chip and the segments. On second thought, that shouldn't be difficult at all. View the following in a fixed pitched font: .AAA. A A A A A A .AAA. B B B B B B .BBB..B 444... 1 3 . 1 3 . 1 3 . .222. . 1 . 3 . 1 . 3 . 1 . 3 . 222 4 The upper digit represents the two backplanes A and B. The '.' characters show how the backplane segments are connected. The lower digit represents the four segments used to display one digit. Again, the '.' characters show how the segments are connected on the other piece of glass. Using similar technology and the same I2C chip, it should be possible to go to 16 digits with four backplanes. Bob Ammerman RAm Systems

In message <008101c5fb61$633da130$a402a8c0@personalrvuq8e> "microsoftwarecontrol" <KILLspammicrosoftwarecontrolKILLspamyahoo.ca> wrote: > 16*2 lcd module now is 1- 5 $/pcs. why bother even look > at this 12$ thing? > > the company still making such product, is out of the date. Two words: Power consumption. HD44780s (and clones) are notoriously inefficient. That and 16x2 LCMs are *huge*. I suspect the 4-digit displays could be made run off a small Lithium cell. Again, shame they cost about $12 each.. I've got some projects that got shelved because I couldn't find a small, low-power 8-digit numeric display :( Later. -- Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT RemoveMEphilpemTakeThisOuTphilpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook Never underestimate the power of human stupidity -- Robert A. Heinlein

size and weight is one point. But, only 4 digits? it is not suitable for pic type device at all. pic has much more information than one line of number, be needed to display. No display, no function, am I right? Also, now a day hd447800 lcd module can be very thin (even with EL backlight) and very small. For the sake of size and weight, to pay $12 and lost capability of neccessary information display? it is absolutely wrong doing. Before I met the point to choose one line 7-seg number or 2*16 lcd module? After some comparing I reached conclusion: all of my future pic project will be using at least 2*16. By the way, firmware for 2*16 is even smaller. {Original Message removed}

On Dec 7, 2005, at 7:19 PM, microsoftwarecontrol wrote: > But, only 4 digits? it is not suitable for pic type device at all. > pic has much more information than one line of number, be needed > to display. No display, no function, am I right? Well, it seems just about right for the application on the web page; altimeter for model planes and rockets. 0 to 9999 feet is plenty for anything that needs to be that small. You have to realize the extremes that other vendors have gone to to keep their equivalent products similarly tiny. One used a .5 inch beeper and would beep out the altitude: "long_pause beep beep beep short_pause beep beep beep beep short_pause beep beep" = 342 feet :-) (Really!) At work we seem to use a lot of HCMS2904-style displays (4 digit dot matrix LEDs; about 18x10mm; usually one or two per "big" board in a chassis. They're power hungry beasts and complex to interface to, and more than $12 ! > Also, now a day hd447800 lcd module can be very thin > (even with EL backlight) and very small. Please tell me where I can get some! Something 15mm by 30mm with 8 to 16 characters would be great. And under $12 in ones... Sure, a 4 digit display doesn't suit every application; but this particular display fill a niche that is often neglected. BillW

> > But, only 4 digits? it is not suitable for pic type device at all. > > pic has much more information than one line of number, be > > needed to display. No display, no function, am I right? There's no rule about how much or how little information you have to display. You're saying as the PIC gets bigger so should the LCD ? > Well, it seems just about right for the application on the web > page; altimeter for model planes and rockets I have a probe thermometer that uses a similar display. Imagine making something similar with a 10F and an iButton, or any type of sensor (strain gauge ? lux ? revs ?). You could even record maxima-minima in dynamic environments (eg the altimeter - record g and height)

>-----Original Message----- >From: spamBeGonepiclist-bouncesspamBeGonemit.edu [TakeThisOuTpiclist-bouncesEraseMEspam_OUTmit.edu] >Sent: 08 December 2005 03:20 >To: Microcontroller discussion list - Public. >Subject: Re: [EE] Cute little 4-digit display... > > >size and weight is one point. But, >only 4 digits? it is not suitable for >pic type device at all. pic has much >more information than one line of >number, be needed to display. >No display, no function, am I right? > The amount of information you need to display is hardly related to the power of the microprocessor. Most of my projects use the largest available 18F parts, and have no display at all... >Also, now a day hd447800 lcd module >can be very thin (even with EL backlight) >and very small. For the sake of size and weight, >to pay $12 and lost capability of neccessary >information display? it is absolutely wrong doing. > But having more than 4 digits may not be neccesary! Why use a huge 2*16 display if you only need to display the numbers 0-9999? A 2x16 display won't even fit into many/most "hand held" instrument style project boxes. >Before I met the point to choose one line 7-seg >number or 2*16 lcd module? After some >comparing I reached conclusion: all of my >future pic project will be using at least 2*16. >By the way, firmware for 2*16 is even smaller. > Why have you decided that all of your projects will have some kind of user interface? Embedded controllers with no user interface whatsoever are very, very common. If you can use an MSSP module to provide the I2C, I suspect the firmware might actually be smaller. And of course, if you already have I2C devices such as EEPROM etc. then the code will be much, much smaller. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. =======================================================================

>Thanks guys, > >That's the name. It totally escaped me. I wanted >to try them as contacts to a sample in scientific >experiments. Small quntities only, but I wanted >consistancy in the connectors I used otherwise I >just would have ripped out the guts of a cheap calculator. I have had mixed results using these. I used to service a mini computer system that had these to connect daughter PCBs in a communications controller, and they were forever giving us problems. Some would be alright, and others would fail on a regular basis. I would go in and change the zebra strips on the faulty ones, do them up to the required torque, and they would still fail after a while. Eventually the manufacturer changed the style of zebra strip to one that had a gold plated foil around the outside instead of the conductive black stuff through the middle, and all the problems went away.

Phil, On Thu, 08 Dec 2005 00:39:52 GMT, Philip Pemberton wrote: > shame they cost about $12 each.. I've got some projects that got > shelved because I couldn't find a small, low-power 8-digit numeric display :( I suppose using two of the 4-digit ones side-by-side is a non-starter? :-) They seem to be generous on the exchange rate - changing to GBP pricing it shows £6.33, an exchange rate of about $1.89:£1, which hasn't been the case for several months. I'm on the point of impulse-buying one, but adding shipping brings it to nearly £9, and that is too expensive just for the fun of it. Cheers, Howard Winter St.Albans, England

Mine only has to work once, but there are some extreme conditions involved. Sitting in a bath of liquid Nitrogen & subjected to a pulsed magnetic field of 25 tesla. I'm not convinced they will work for me, but thought I'd cool one down & see how it behaved. No point in trying this if I can't get a reliable supply though. That said, I'll be working with this stuff next week so if I can find a sacrificial calculator..... Joe {Quote hidden}> > I have had mixed results using these. I used to service a > mini computer system that had these to connect daughter PCBs > in a communications controller, and they were forever giving > us problems. Some would be alright, and others would fail on > a regular basis. I would go in and change the zebra strips on > the faulty ones, do them up to the required torque, and they > would still fail after a while. Eventually the manufacturer > changed the style of zebra strip to one that had a gold > plated foil around the outside instead of the conductive > black stuff through the middle, and all the problems went away. > > --

That's my view too, I'm making contacts onto a thin film sample (not a display Alan :) Are there any displays which will work at those extremes of temp anyhow?). If I can get a good contact on 'dry land' then maybe it will be OK when immersed. I think it is unlikly to work, so testing it is a low priority at the moment. If I do get around to doing it, I'll pass along my findings..... Joe > > Yikes.. Zebra strips work by being flexible, and I kind of > doubt that at those temperatures, they will be more flexible > than say, glass..? > > > --

> -----Original Message----- > From: RemoveMEpiclist-bouncesTakeThisOuTmit.edu [piclist-bouncesEraseME.....mit.edu] On Behalf > Of Joe McCauley > Sent: Friday, December 09, 2005 4:46 AM > To: 'Microcontroller discussion list - Public.' > Subject: RE: [EE] Cute little 4-digit display... > > That's my view too, I'm making contacts onto a thin film sample (not a > display Alan :) Are there any displays which will work at those extremes > of > temp anyhow The other side of this is that the LCD material will also not work at those temperatures. What about taking your data out by pulsed IR, and reading it on something at a more normal temperature?

Well as Alan pointed out earlier, we are starting to stray a bit from EE. I'm of the view that we're only marginally doing so, so I'm not changing the tag just yet. I'm doing a 4 point resistance measurement on a thin film sample subjected to a large pulsed magnetic field (25T). Imagine 4 contacts in a row on a strip of metal. I have to pass a current through the sample via the outer 2 contacts and measure the voltage developed across the middle 2 contacts during the field pulse. At normal room temp the elastomer connector would be ideal for making contacts, just sandwich a piece between 4 contacts on a PCB and the sample & off you go. At 77 degrees Kelvin it might all go to H***. If anyone has any other ideas on how to do this that does not involve silver paint daubed on the sample I'm all ears :) If anyone really feels that this should be OT please feel free to point that out or indeed to change the tag if replying. Joe > The other side of this is that the LCD material will also not > work at those temperatures. > > What about taking your data out by pulsed IR, and reading it > on something at a more normal temperature? > > > > > --

>I'm doing a 4 point resistance measurement on a thin film >sample subjected to a large pulsed magnetic field (25T). Hmm, I'm wondering if you will see some Hall Effect type things happen at that field strength. >Imagine 4 contacts in a row on a strip of metal. ... What thickness is the base? What is the element of the metallisation? > At normal room temp the elastomer connector would be >ideal for making contacts, just sandwich a piece >between 4 contacts on a PCB and the sample & off you >go. At 77 degrees Kelvin it might all go to H***. > >If anyone has any other ideas on how to do this that >does not involve silver paint daubed on the sample >I'm all ears :) I would suggest using the edge mount pins used on ceramic hybrid circuit bases, to make them into DIP type assemblies. I know people on this list have pointed at suppliers of these in the past, so if noone answers about them you may need to dig in the archives. >If anyone really feels that this should be OT please feel >free to point that out or indeed to change the tag if replying. I am happy with EE. I cannot see anything in the content that I would regard as not being of engineering interest.

> Subject: RE: [EE] Cute little 4-digit display... > > Well as Alan pointed out earlier, we are starting to stray a > bit from EE. > I'm of the view that we're only marginally doing so, so I'm > not changing the tag just yet. No problem with not changing the tag... This IS however a hijacked thread which is no longer about a "Cute little 4-digit display" I'm not going to enforce it, but I think lots of people would appreciate it if, in general, people who change the subject of a thread in terms of what they are posting, would also change the subject line to reflect that. In this case, Alan's point was that anyone reading the subject line starts to think about LCD displays, and then reads your post from that point of view. It makes it difficult to understand what you are saying because it is out of context with the subject line. I'm a little amazed that this is not obvious to people, but I don't mean that to sound as if I feel you (or anyone else) is stupid or rude. I guess I have just thought about it a lot and need to recognize that others may not have thought about it at all. Please think about it. > > If anyone really feels that this should be OT please feel > free to point that out or indeed to change the tag if replying. It doesn't need to be OT. It would be nice if the subject line matched the content of the post. --- James Newton: PICList webmaster/Admin EraseMEjamesnewtonpiclist.com 1-619-652-0593 phone http://www.piclist.com/member/JMN-EFP-786 PIC/PICList FAQ: http://www.piclist.com

On Fri, 9 Dec 2005, Joe McCauley wrote: > That's my view too, I'm making contacts onto a thin film sample (not a > display Alan :) Are there any displays which will work at those extremes of > temp anyhow?). If I can get a good contact on 'dry land' then maybe it will > be OK when immersed. > > I think it is unlikly to work, so testing it is a low priority at the > moment. If I do get around to doing it, I'll pass along my findings..... Imho the chances that the liquid crystal substance will be still 'liquid' at LN2 temperature are about frozen ... But a mechanical display designed not to bind when cooled down should work fine. F.ex. those magnet flipper displays used on public transport should work. Also LEDs should work (with very high efficiency) unless the die cracks off the substrate due to mechanical stress when cooling it down. Peter

----- Original Message ----- From: "Joe McCauley" <RemoveMEjoe.mccauleyEraseMEEraseMEtcd.ie> To: "'Microcontroller discussion list - Public.'" <RemoveMEpiclistspam_OUTKILLspammit.edu> Sent: Thursday, December 08, 2005 11:55 AM Subject: RE: [EE] Cute little 4-digit display... > Mine only has to work once, but there are some extreme conditions > involved. > Sitting in a bath of liquid Nitrogen & subjected to a pulsed magnetic > field > of 25 tesla. I'm not convinced they will work for me, but thought I'd cool > one down & see how it behaved. > I got a funny feeling that a rubber strip isn't going to do to well in an LN2 bath. Can anybody say solid rocket booster o-ring? Bob Ammerman RAm Systems

> >I'm doing a 4 point resistance measurement on a thin film >>sample subjected to a large pulsed magnetic field (25T). How about four small pressure (ie spring loaded) contacts. Say little bits of phosper bronze with a "dimple" on one end to contact the sample and the other end soldered to a little circuit board, or even directly to some kind of connector. In fact, now that I am thinking of it, how about using an IC socket (non-machined pin style) or loose pin .1x.1 connector to both provide the contacts and a frame to hold them at a known spacing. Bob Ammerman RAm Systems

James, Point taken. Sorry about that. From some of the replies coming back I can see that you are of course correct. Future mails on this thread would be better labeled as 'Connections at 77K' as Bill has already done. Joe {Quote hidden}> -----Original Message----- > From: RemoveMEpiclist-bouncesTakeThisOuTspammit.edu > [EraseMEpiclist-bouncesspamspamBeGonemit.edu] On Behalf Of James Newton, Host > In this case, Alan's point was that anyone reading the > subject line starts to think about LCD displays, and then > reads your post from that point of view. It makes it > difficult to understand what you are saying because it is out > of context with the subject line. > >

Alan, Comments below. {Quote hidden}> -----Original Message----- > From: RemoveMEpiclist-bouncesKILLspammit.edu > [piclist-bouncesSTOPspamspam_OUTmit.edu] On Behalf Of Alan B. Pearce > Sent: 09 December 2005 17:23 > To: Microcontroller discussion list - Public. > Subject: Re: [EE] Cute little 4-digit display... > >Imagine 4 contacts in a row on a strip of metal. > ... > > What thickness is the base? What is the element of the metallisation? The base thickness is not too important. The metal to be measured could be anything, but is 100-200 nm thick so is very delicate. > > I would suggest using the edge mount pins used on ceramic > hybrid circuit bases, to make them into DIP type assemblies. This is an idea I should have thought of myself. (Doh) If these were cheap enough, it might be possible to evaporate gold contacts directly onto the ceramic & then evaporate the sample over that. I'll have to check it out. Thanks, Joe