Multi Calculator Kit

[Robert VM]

(06-08-2018 04:58 PM)Zaphod Wrote:  I think I’ve looked through all pages of this thread , but can’t find any real life photo’s of the thing?

Anyone?

post# 29 (page 2).

[revwillie]

(06-08-2018 04:58 PM)Zaphod Wrote:  I think I’ve looked through all pages of this thread , but can’t find any real life photo’s of the thing?

Anyone?

   

[revwillie]

(06-08-2018 06:13 PM)Robert VM Wrote:  

(06-08-2018 04:58 PM)Zaphod Wrote:  I think I’ve looked through all pages of this thread , but can’t find any real life photo’s of the thing?

Anyone?

post# 29 (page 2).

post #65 has Tony's enclosure and overlay and some excellent suggestions on membrane keyboard making.

[teenix]

Hi all,

There is only one lucky last MutiCalc kit remaining.

As expected, the sale of these kits has slowed down now and I'm not sure it is worth getting a new stock of parts given that to do this reasonable cheaply, I have to buy in quantity. And of course, the missing case is a bit of a downer.

Many thanks to those that supported the kit, maybe more in the future, who knows

cheers

Tony

[Gerson W. Barbosa]

(06-29-2018 03:03 AM)teenix Wrote:  Hi all,

There is only one lucky last MutiCalc kit remaining.

I’ll take it if still available – and the previous poster is not interested. I would need it assembled and tested, please.

Thank you very much!

Gerson.

[teenix]

(06-29-2018 03:03 AM)teenix Wrote:  There is only one lucky last MutiCalc kit remaining.

First in best dressed, all gone now. It's been fun :-)

cheers

Tony

[revwillie]

I've been slowly working on an enclosure with that Hammond case I linked to earlier.

To make the multicalc fit, a lot of plastic material has to be removed from the case. The real challenge is getting the switches, keys and display to an optimal height for the type of overlay membrane you use. I might be able to buy another case now and use the first as a measurement guide such that I could possibly remove less plastic from the front face.

Also, to keep the PCB secure inside the case, I ground notches into the pcb that you can see in the pictures. I used a rotary tool (aka dremel) and took things slow and careful so as not to damage the circuits in the PCB. About 1/8" of PCB material had to be ground off the end by the USB port as well.

I obviously had to move the battery holder around which is clear in the photos. I was pretty happy to fit everything inside including the battery holder. I filed out a hole to allow access to the USB port. For now, my overlay solution is quite crude. I print an overlay on paper, trim it with scissors and lay it under a piece of clear packaging scrap secured with electrical tape along the edges. placement of the overlay requires a feeling through the paper for the key tops below. I think the clear plastic I chose is too stiff because the '9' key gets accidentally pressed often and I believe that multiple keys are being pressed at times causing the calculator to reset.

I tried blacking out the clear plastic over the LED display using a black permanent marker. The effect can be seen in the last two pictures. It's kind of cool.

So for the time being, I have something I'm not afraid to drop into my briefcase. I can stick with the HP-55 for a while until I try another overlay solution. Tony suggested printable magnetic vinyl sheets and I think I'll try to buy some.

Pictures so far

[teenix]

Nice case.

I tried with a different model case from Hammond but after I modified it to suit the kit I realised the LEDs would interfere with the case moulding and unfortunately haven't had time to try again. I briefly looked at the idea of a touch pad which would simplify the case design but then it would not have the "button" feel.

cheers

Tony

[Harald]

I think what we need is a 3d printed custom housing for the calculator. The issue with that is, that this requires both skills and time...

[Paul Dale]

I agree, a 3D printable enclosure would be fantastic.
Sadly, I lack both the skills required and the time.


Pauli

[Robert VM]

Made this -sort of- keyboard for MultiCalc. Used the simplest "Live Hinge" design
that is used to make a flexible surface using a laser cutter.

Maximum key travel is about 0.5 mm. Plexiglass being very brittle and the keys having a very
small geometry. The height of the switches will have to be very uniform for this to function.

I'm not sure how this will fit in a laser cut case and how to use the keyboard template:
on top or below the hinges.
Below impairs the readability. On top hampers key movement even when the
template is printed on ordinary paper.

   
   
   

[teenix]

Hi Robert,

A nice looking keyboard and enclosure is certainly the bane of this project.

That looks like a lot of work, I hope it comes off.

cheers

Tony

[Robert VM]

Hi Tony,

Sorry for the long delay.
Not more work than designing a keyboard overlay, I'm sure (you did about 25).
Not to mention the assembly of the kits, it seems like you've done most of them as well.

It does take me a lot of time to figure out how to design an enclosure with lasercut plexiglass.

Would indeed be nice to also have an affordable enclosure for the MultiCalc.

Open Office unfortunately renders the keyboard overlays in Picasso style.
I had to use an online PDF conversion tool, then vertical scaling was somewhat off.

Are the PCB overlays slightly larger than 2 to 1?

I wondered at the yellow labels of the HP19 for keys "GSB", "GTO" and "SST".

I'll mail a real specimen when i get through the next iteration.

Best, Robert

Picture with overlay:
   

[teenix]

(08-21-2018 12:15 PM)Robert VM Wrote:  Hi Tony,

Are the PCB overlays slightly larger than 2 to 1?

I wondered at the yellow labels of the HP19 for keys "GSB", "GTO" and "SST".

They were scaled at 1:1 when directly printed from Word. My version is 2007. I don't want a later one if I can help it.

I know PDF conversions don't scale exactly. It's frustrating with my PCB designs which are created in Protel format on an old Win95 machine. I don't have a printer that can print them directly from that PC.

Not sure about the yellow labels, I cannot find them. They are white text on the 3 buttons above the enter key.

cheers

Tony

[revwillie]

(08-21-2018 12:15 PM)Robert VM Wrote:  Are the PCB overlays slightly larger than 2 to 1?

I have to change from A4 paper to US Letter size before printing to get the correct sizing.

Not having a laser cutter or a 3D printer, I have been making incremental improvements to the Hammond case enclosure. I bought a second one and drilled/filed out smaller openings in the front using the first case as a guide. I have magnetic shielding foil tape (steel) which I plan to apply to the new case front so that printable magnetic vinyl sheet can be used to make the overlays. The next issue to overcome is incorporating a thinner battery so that the key tops don't extend from the front of the case. When the overlay floats over all of the keys, a key press in one area can interfere with nearby keys. Also, the magnetic sheet is held away from the metal tape.
If I can get the key height right, key presses would push the vinyl sheet down into each drilled hole for its respective key.

[Robert VM]

Sorry Tony, there's certainly no need for a later version Word. The problem is with the Open Office Writer.

I meant the yellow "SCI" "ENG" "FIX" for said keys on the 19 overlay. The order seems to be different on the actual machine.

No laser cutter here either. I'm lucky there is a FabLab facility in town. Individuals may use the machines for free if they publishe the design and don't sell the result.

[teenix]

(08-23-2018 12:57 PM)revwillie Wrote:  

(08-21-2018 12:15 PM)Robert VM Wrote:  Are the PCB overlays slightly larger than 2 to 1?

I have to change from A4 paper to US Letter size before printing to get the correct sizing.

I'll have to try that out.

(08-23-2018 01:41 PM)Robert VM Wrote:  I meant the yellow "SCI" "ENG" "FIX" for said keys on the 19 overlay. The order seems to be different on the actual machine.

Missed that, all fixed, thanks.

Reposted download.

cheers

Tony

[grsbanks]

(08-23-2018 12:57 PM)revwillie Wrote:  I have to change from A4 paper to US Letter size before printing to get the correct sizing.

If you're printing a PDF, the chances are that the option "scale to fit" is checked in the print options. Try "Print actual size" instead.

[revwillie]

(08-23-2018 12:57 PM)revwillie Wrote:  Not having a laser cutter or a 3D printer, I have been making incremental improvements to the Hammond case enclosure. I bought a second one and drilled/filed out smaller openings in the front using the first case as a guide. I have magnetic shielding foil tape (steel) which I plan to apply to the new case front so that printable magnetic vinyl sheet can be used to make the overlays. The next issue to overcome is incorporating a thinner battery so that the key tops don't extend from the front of the case. When the overlay floats over all of the keys, a key press in one area can interfere with nearby keys. Also, the magnetic sheet is held away from the metal tape.
If I can get the key height right, key presses would push the vinyl sheet down into each drilled hole for its respective key.

Hammond updates: I added a few photos to the shared album:LINK

Steel foil tape is expensive and much harder to shape than I expected. It's not like aluminum foil or the aluminum foil tape used to seal up HVAC ducts. It's thicker and tougher and every edge is razor sharp. Tony's initial suggestion was to use small permanent magnets and that's a direction I might go in. The magnetic sheet material from old refrigerator magnets will cling to the steel tape surface, but not very securely. I finally have the keys fully working again after many short sessions of forming the tape followed by nursing my wounds. The pictures show my adaptation of a galaxy SIII battery for power. It fits nicely behind the pcb using a cut-down portion of an external battery charger. No charging circuitry is included, it's just a battery holder. I can use a little bit of soft packing foam behind the battery in the case when the screws are tight and this keeps the battery secure while also damping the noise of key clicks.

[Leviset]

I’ve already told you all BUT “I’m totally useless on the electronics side but good on the Pure Mathematics and Algorithm issues’
I bought a half-completed μWatch Calculator kit. I know it started in 2007 and now I can’t find anyone to help.
I did manage to get the setup instructions coming up on the screen BUT when I folded over the ribbon cable so that the 2 parts could be bolted together to form the watch the red +ve wire from the battery came off from the PCB. I got a friend to re-solder the wire back on, which he did very professionally. However I then couldn’t get the screen to work all. Then the ribbon cable from the PCB to the LCD came away at the LCD connector. It was covered in some black goo which when I cleaned it off the 16 metal connectors were exposed showing on the LCD board. I’m not sure if these are the broken off terminals from ribbon cable, now stuck to the LCD board? (Some pictures attached below).
(1) Does anyone know and can tell me the exact LCD screen I need and would that replacement come with a 16 pin cable already attached to it please?
(2) I bought from Amazon a “MakerHawk 2pcs I2C OLED Display Module 0.91 Inch I2C SSD1306 OLED Display Module Blue I2C OLED Screen Driver DC 3.3V~5V for Arduino” as it looked the right component, but for the life of me I can’t see anywhere where you could attach a ribbon cable?
Any help would be greatly appreciated
Dennis
Sorry it won’t let me attach the images, exceeds available space.