Calculator displays

[Warbucks]

Update on calculator display options:

Individual red 7 seg leds are available though mounted two per small pcb. Lot size is reasonable.

Also available 14 (+3 punctuation) seg individual red leds.

LCD displays that can display a nice "font" instead of what the 41 presented us with.
For purists, the old style is available too.

I was also shown an assembly that would let me change the display in the field with a selection of display modules. A 41 with red leds or how about a small led capacitive touch screen that will display any font any color?

On a different front, there are some new arbitrary precision algorithms for elemental
functions. I'm going to implement them for testing. I need to make sure of their provenance though.


Edit:

In the zip file are two images, the one with 9 leds if you cut the end two off, that is what he has. He also said the five led chip is available. I await his remit.

Thanks for your time and advice.

JW

[Harald]

It would be helpfull to know the sizes of the displays. Assuming theses are roughly the size of the original HP LEDs, the 7 segment ones would be my choice for a calculator that emulates all the HP LED calculators (like Tonys Multicalculator)
Alternatively a dot matrix display would be interesting to build a much more powerfull LED calculator (lets call it the WP34LED ;-)) A 14-segment display would be a step in the right direction. Maybe we could have an HP41LED.

Can we see pictures of sample LEDs?

Cheers,
Harald

[Helix]

(05-28-2018 06:33 AM)Warbucks Wrote:  In the zip file are two images, the one with 9 leds if you cut the end two off, that is what he has. He also said the five led chip is available. I await his remit.

There is an error in your link, so I'm posting the images.

I would vote for the 5 LED chip, similar to the HP displays, and more appealing in my opinion than the 9 LED model.
A 14 segment LED in the same style would be very original.

[Harald]

(05-30-2018 12:44 AM)Helix Wrote:  

(05-28-2018 06:33 AM)Warbucks Wrote:  In the zip file are two images, the one with 9 leds if you cut the end two off, that is what he has. He also said the five led chip is available. I await his remit.

There is an error in your link, so I'm posting the images.

I would vote for the 5 LED chip, similar to the HP displays, and more appealing in my opinion than the 9 LED model.
A 14 segment LED in the same style would be very original.

If I had just seen the pictures without any text to accompany them, I would have been convinced that what we are looking at is an old HP buble LED module and an east German LEDs mate by RFT.
Now I am confused, did the Chinese make 1:1 copies of those 40 year old designs?!?

Edit: Guess I was wrong: the second picture is of a Commodore Minuteman display : http://www.vintagecalculators.com/html/c...plays.html

Edit 2: I read the original post again and think that these are only examples, not the real units. So we'll have to wait and see.

[teenix]

(05-30-2018 07:42 AM)Harald Wrote:  Now I am confused, did the Chinese make 1:1 copies of those 40 year old designs?!?

The decimal point is not inside the cdeg segments, so more similar to a design that used to be generally available, but still, it would be good to know a supply is available if needed

cheers

Tony

[Accutron]

(05-30-2018 07:42 AM)Harald Wrote:  the second picture is of a Commodore Minuteman display

The individual 7-segment displays are Monsanto MAN3A. Litronix was a second source for this part, and they were used by a number of different calculator manufacturers, including TI.

Here are some better photographs...

http://www.decadecounter.com/vta/article...p?item=364

[Helix]

(05-30-2018 07:42 AM)Harald Wrote:  Edit 2: I read the original post again and think that these are only examples, not the real units. So we'll have to wait and see.

I agree that we need some clarification on what is really available. I may have misunderstood Warbucks' post.

[Harald]

(05-30-2018 11:46 AM)Accutron Wrote:  The individual 7-segment displays are Monsanto MAN3A. Litronix was a second source for this part, and they were used by a number of different calculator manufacturers, including TI.

Ah, now I understand why I thought they were east German LEDs. The Litronix LEDs were used in some RFT calculators...

[Chasfield]

OLED displays have some very desirable characteristics (contrast, power consumption).

Winstar make a nice 16 character x 2 row one in many colours, including red. The carrier PCB is a bit bulkier than you might want though (84mm wide).

[Warbucks]

Greetings:

I am sorry, I should have been clearer.

Those are examples only as he did not have any on hand -- he was to get samples this week.

The rep told me the 5 led package is an exact copy of the old HP bubble leds. It may even have the hp part number underneath. Stock is of old manufacture, but some stock is just 3-4 years old. I guess that means we will be seeing retro calcs from China?

If it has HP on it with the part number, I will not buy them for this project as I do not want to distribute counterfeit goods or get the evil eye from HP.

He also has access to the old German type flat leds (Copies? Not clear,) as well as individual leds soldered two per small PCB.

I trust this clears up any confusion. I should have samples this week or maybe next.

Regards

JW

I forgot to ask, does anyone know the hex color code for the beige case that the 29c had? Black was easy.
I do not want to trust my eyes.

Thanks again.

[Harald]

(05-31-2018 11:11 AM)Warbucks Wrote:  The rep told me the 5 led package is an exact copy of the old HP bubble leds. It may even have the hp part number underneath.

He also has access to the old German type flat leds (Copies? Not clear,) as well as individual leds soldered two per small PCB.

Once you have samples, i might be interested in buying some of the leds. Maybe we can organise a group by.

Cheers,
Harald

[Garth Wilson]

These dot-matrix LED displays are very small, nice, end-to-end and side-to-side stackable, come in several colors, but are quite expensive:
https://www.broadcom.com/products/leds-a...interface/

[teenix]

(06-05-2018 09:07 AM)Garth Wilson Wrote:  These dot-matrix LED displays are very small, nice, end-to-end and side-to-side stackable, come in several colors, but are quite expensive:
https://www.broadcom.com/products/leds-a...interface/

Very power hungry though - 16 digits consume up to 5 watts @5V.

cheers

Tony

[Garth Wilson]

(06-05-2018 01:35 PM)teenix Wrote:  

(06-05-2018 09:07 AM)Garth Wilson Wrote:  These dot-matrix LED displays are very small, nice, end-to-end and side-to-side stackable, come in several colors, but are quite expensive:
https://www.broadcom.com/products/leds-a...interface/

Very power hungry though - 16 digits consume up to 5 watts @5V.

That's the absolute max, right? IOW, all pixels turned on continuously (which you'll never have in real life), and maximum brightness, which IMO is too bright unless you're outdoors. I've seen these in a brightly lit lab, and they had to brightness up too bright even for that environment. 1.2W per four characters is the specification for "If you exceed this amount, you may cause irreversible damage." You can set the brightness in software, and the display has its own strobing circuitry, and pixel duty factor is something like 20%. I have a couple here that I keep meaning to try out on the workbench. I just have too much work right now to take the time though.

LEDs do take a lot of current though. I know they've gotten a lot more efficient in recent decades, but my TI-58c and TI-59 were just comfortable indoors and just about impossible to see outdoors, and although TI said a battery charge was good for "up to" four hours, the truth was really more like two hours, even when the batteries were brand new, and to save power, I would leave nothing but a single decimal point in the display when I had it idling between calculations or program runs. Getting the HP-41cx after that was a dream, not just to be able to display alpha, but that I could go up to two years on a set of alkaline batteries, or two months when it was getting used all day every day to control test equipment via HPIL.

[jjohnson873]

If there is a new source (or even New Old Stock) of the HP QDSP-6064 LED displays, I'd be very interested in acquiring some of them. I purchased quite a few of them when Sparkfun found thousands of them, NOS. Alas, the stock was depleted. ~ Jim J.~

[teenix]

(06-06-2018 02:34 AM)jjohnson873 Wrote:  If there is a new source (or even New Old Stock) of the HP QDSP-6064 LED displays, I'd be very interested in acquiring some of them. I purchased quite a few of them when Sparkfun found thousands of them, NOS. Alas, the stock was depleted. ~ Jim J.~

I know there will never be a huge demand for these, but world wide, electronic hobbyists would still like to use them, maybe with just enough interest for small production runs.

cheers

Tony

[Garth Wilson]

The same goes for tiny intelligent character LCDs. Smartphones' characters are usually so much tinier; so why don't they make intelligent character LCDs with characters less than .2"?! They would be useful not just for calculators, but also for displaying status and for debugging on small single-board computers. There was a German company years ago that supposedly had one, but apparently it was only vaporware. I was never able to get one. In my work in the mid to late-1980's, we considered having a custom LCD made for a product we were developing. The NRE at the time was a couple thousand dollars IIRC. It seems like it would be worth it today, to make that and put a standard Hitachi 44780 controller IC on it. I expect the NRE would be less today, in the same way that the cost of PC boards in small quantities has come way, way down, putting them within reach of hobbyists.

[jjohnson873]

The small OLED dot matrix displays have dropped significantly in price and have become a standard for many development boards and projects that need a complex display with varying character sizes. These displays can be purchased either in monochrome or color and use very little power.

[teenix]

(06-06-2018 01:33 PM)jjohnson873 Wrote:  The small OLED dot matrix displays have dropped significantly in price and have become a standard for many development boards and projects that need a complex display with varying character sizes. These displays can be purchased either in monochrome or color and use very little power.

They seem to be the way of the future for generic displays.

I've looked into these for the MultiCalc. In small quantities the cost can be up to 5 times that of LED displays.

I have found that the 100 x 16 pixel RED OLED will just work for the display requirements for all the emulated models. Power requirements are also similar.

For the ones I have seen, the active display width is similar at 60mm, however the overall module width is around 80mm. Obviously for manufacturing purposes they seem to use generic module housings for different size displays. If they created a smaller modules closer to actual the size of these display types then, cost aside, they could be ideal.

cheers

Tony

[mfleming]

Newhaven makes a nice 128x32 blue OLED that is close to the size of a 42S display, but is over $20 in unit quantities and doesn't drop below that until qty 500+. The display is 27mm x 56mm but the carrier board with drive electronics is larger at 43mm x 63mm. Has font support for a very large number of languages. Parallel, serial and I2C interfaces too!

https://www.onlinecomponents.com/newhave...p=44424825

~Mark