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48G Re-creation Project (fantasy)
11-07-2019, 08:43 PM (This post was last modified: 11-07-2019 09:51 PM by lemontea.)
Post: #45
RE: 48G Re-creation Project (fantasy)
(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?
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RE: 48G Re-creation Project (fantasy) - lemontea - 11-07-2019 08:43 PM

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