48G Re-creation Project (fantasy)

[maxrk]

[quote='lemontea' pid='122913' dateline='1572502849']
I found the switch they use.

Dome shaped. SMT.

$10 for 50 of them.

Very nice!

[sunhp]

This is amazing to me and is really helping understand some of the concepts about electrical engineering and computer science and also machine language

How do CPUs read machine code?

[MattGreer]

I read the first page, skipped the rest, and I am now probably off topic.

I would buy a modern HP48 in a heartbeat. I just got a 50G and, after 20+ years with the 48 I'm really having problems adjusting. Doggone enter key in the wrong place, ugh.

My wish list if it wasn't already posted:

• Give me the HP Prime Screen - you can do this
• USB connectivity so I can dump stuff to/from the computer, do programming on the computer and save a file to the calc
• Faster processor of course
• More memory
  

That's it. Make it faster, have more space, and easier to back up. I don't know if it was perfect out of the box or I'm just so used to it that I can't change. Either way, I'd buy this thing in a heartbeat, almost no matter the cost.

[compsystems]

Another option is to develop an emulator (hp48-50 series) for the project.
https://symbolibre.org/en/

[lemontea]

(11-07-2019 08:13 PM)MattGreer Wrote:  I read the first page, skipped the rest, and I am now probably off topic.

I would buy a modern HP48 in a heartbeat. I just got a 50G and, after 20+ years with the 48 I'm really having problems adjusting. Doggone enter key in the wrong place, ugh.

My wish list if it wasn't already posted:

• Give me the HP Prime Screen - you can do this
• USB connectivity so I can dump stuff to/from the computer, do programming on the computer and save a file to the calc
• Faster processor of course
• More memory
  

That's it. Make it faster, have more space, and easier to back up. I don't know if it was perfect out of the box or I'm just so used to it that I can't change. Either way, I'd buy this thing in a heartbeat, almost no matter the cost.

Haha you are in the same club as some of us here.

For your wishlist, the device I envision has a few changes.

The screen won't be LED like the Prime. It will be e-ink, and maybe backlit. I want this to run off AA batteries.

USB connectivity... maybe not. Don't want to deal with drivers, etc. so only IRDA (the same one originally supported on the original device). We can consider SD card access like the 50g. But that makes it more complicated with more potential bugs, etc. If the USB access is a no-brainer (natively supported by whatever underlying hardware ultimately chosen) then that's fine.

Folks, I've continued to mull over this project. Actually what I have in my head is quite a lot to type, but I want to keep things focused and practical, so we can actually get this project moving along (I estimate maybe it will become a reality in 2 years, with a lot of help from everyone here).

I think it's possible at this time to already take an existing 48 and turn it into the newfangled 48. The screen will be replaced with the higher contrast one (harvested from the 39G). The keyboard circuitry will be redone with a new PCB and the dome switches, replacing the flaky plastic sheet thingie.

To "glue" the whole thing together, 3D printed parts will "perfectly" align the LCD, zebra strips, keypad + new keyboard PCB, and main CPU PCB. A new back case will be 3D printed, to accommodate the batteries (can even change it to 3 x AA), and anything else that doesn't align, with the replaced components.

Also while we are at it, can upgrade the RAM as well. So a 32MB 48G can be a 128MB one. I haven't thought about the GX. I don't have a GX to examine and would not want to open up a working GX anyway. I've only disassembled for-parts 48Gs.

Oh yeah, I am thinking to cut off those metal twist tabs that lock the keyboard to the main PCB, and (after everything is aligned with 3D printed parts) the necessary soldering can be done with jumper wires to make the electrical connections the metal twist tabs used to make.

After this device has been assembled (probably using a 48G with a broken LCD), we can look into replacing each component, until the entire thing is redone with all new components and nothing salvaged from vintage units.

Printing a new keyboard will be challenging. I was looking at lots of resin molding YouTube videos. We can print a model, pour a silicone mold, then use that mold to make the resin casted keyboard. For colors, we can color print (inkjet or laser) overlays to be stuck onto the keyboard, or print recessed gaps for the lettering and then use crayons or something to colorize them (this is something I remember from Dungeons & Dragons days, coloring 20-sided dice with crayons).

Hope my rambling brain download makes at least some sense to you guys.

Continued ideas and thoughts welcome!

When I have time I am playing with OpenSCAD to create the aforementioned parts. No progress yet on the keyboard PCB but it seems "straightforward" to me, except how to connect that to the main PCB. I might buy 50 of those dome switches anyway just to keep on hand. I guess we can reuse the original circuit layout from the plastic flex sheet?

[lemontea]

There is another crazy makeshift idea I have, to create a 48G stand-in.

Take a 50G/49G+ and use everything except the keyboard.

3D print a new keyboard putting the ENTER key in the "correct" place :-)

Also "fix" the directional arrow keys, back to the keyboard.

Then rewire everything with the new switches and keyboard PCB so the modification is transparent to the device. Reassemble again using 3D printed case.

[lemontea]

(11-07-2019 08:35 PM)compsystems Wrote:  Another option is to develop an emulator (hp48-50 series) for the project.
https://symbolibre.org/en/

Very interesting they use the Pi Zero

https://symbolibre.org/wp-content/upload....pdf#page8

[lemontea]

I don’t like them using the lithium battery.

These can be a hassle to source in the future (think 10 or 20 years later) and the user has to desolder, resolder, and hope the battery quality is good enough it won’t catch fire, etc.

This is why I keep mentioning AA batteries. And this power constraint will then determine the CPU and screen type.

[lemontea]

I want to double check before buying 100 switches.

Make sure it's actually the best one for our purposes.

I'll take a look when I have time.

This might add 3 months to our 24 month lead-time (lol).

https://www.digikey.com/products/en/swit...geSize=500

Anyone have experience with the other switch types? Is the dome one the best tactile choice?

[MattGreer]

(11-07-2019 08:46 PM)lemontea Wrote:  3D print a new keyboard putting the ENTER key in the "correct" place :-)

Also "fix" the directional arrow keys, back to the keyboard.

This person knows their calculators. I salute you kind ma'am/sir!

[MattGreer]

I'm good with a non-color screen.

Definitely stick with AAA or AA batteries. Rechargeables are not desirable for various reasons in my opinion.

No USB, that's fine. micro SD or SD, that's fine.

I'm about the workflow, the interface, the keys. The 50G is KILLING me right now. I want my Solver back! I haven't even scratched the surface of the things I'm sure are totally wrong with the 50g lololol.

[Marco Polo]

(11-07-2019 08:35 PM)compsystems Wrote:  Another option is to develop an emulator (hp48-50 series) for the project.
https://symbolibre.org/en/

My two cents:
- Target: reproduce HP48gx
- use DM42 platform with different keyboard to match HP48g(x), let's call it DM48
- adapt Emu48 to run on DM48, but keeping the same memory structure (state file + Port 2 memory file up to 4mb)

This way it should be possible:
- to partially use an existing hardware
- to advantage of Emu48 capability to save/load state file
- to reuse existing emulated calculators

Cons:
- improvement of HP48gx platform (rom....) nearly impossible
- emulated calculator memory model stuck on the real one's
- license issue?

[Tim Wessman]

(11-07-2019 11:11 PM)MattGreer Wrote:  

(11-07-2019 08:46 PM)lemontea Wrote:  3D print a new keyboard putting the ENTER key in the "correct" place :-)

This person knows their calculators. I salute you kind ma'am/sir!

Prime has this.

[rprosperi]

(11-08-2019 05:33 PM)Tim Wessman Wrote:  

(11-07-2019 11:11 PM)MattGreer Wrote:  This person knows their calculators. I salute you kind ma'am/sir!

Prime has this.

Since when is the left side on the right side??

[Massimo Gnerucci]

(11-08-2019 10:03 PM)rprosperi Wrote:  

(11-08-2019 05:33 PM)Tim Wessman Wrote:  Prime has this. :P

Since when is the left side on the right side??

Don't get me started on this... :D

Taglines apart, better have it on the operators' side.

[Massimo Gnerucci]

Now, this is an interesting use for the Prime!

;)

[MattGreer]

So trying to catch up here... I'm putting on my Project Manager hat...

Where are we on this? Do we have a solution or a direction in place? What is our current scope and deliverables, and what items have we yet to resolve?

I can contribute money and I'm happy to beta test but other than that, as a chemical engineer, I'm more likely to help you with your plumbing problems than electrical engineering.

[Tim Wessman]

(11-08-2019 10:03 PM)rprosperi Wrote:  

(11-08-2019 05:33 PM)Tim Wessman Wrote:  Prime has this.

Since when is the left side on the right side??

Since right is right and left isn't right.

[rprosperi]

(11-10-2019 07:41 AM)Tim Wessman Wrote:  

(11-08-2019 10:03 PM)rprosperi Wrote:  Since when is the left side on the right side??

Since right is right and left isn't right.

Touché. The important thing is Enter is above the operators, not across from them. I prefer the left; I suppose the right can be right, though a bit less right than the left. Old habits die hard...

[Massimo Gnerucci]

(11-10-2019 01:42 PM)rprosperi Wrote:  

(11-10-2019 07:41 AM)Tim Wessman Wrote:  Since right is right and left isn't right.

Touché. The important thing is Enter is above the operators, not across from them. I prefer the left; I suppose the right can be right, though a bit less right than the left. Old habits die hard...

Hear, hear!
:D