NEW: HP 15C Collectors Edition

[ajay_m]

I had an idea.
One of the neatest features of the hp67 was the magnetic card reader.
Now a modern equivalent would be an ntag216 NFC tag which can store 888 bytes.
You can buy 100 of these for £16.
The reader modules cost about £5.
It ought to be possible to use the voyagersave feature to connect up to a little Pico pi based reader that would let you save programs to tags
Which lets you have a really portable solution for a loadable set of software programs
But without needing a pc.

[battlecoder]

That's actually a neat idea!

But what about perhaps a sort of "craddle" with an SD card slot, an LCD and a couple of buttons? The LCD could show the contents of the card and you could "pick" an image from the list and load it.

That would take less space that an NFC reader and a bunch of RFID tags, and you can potentially store thousands of programs in a single tiny sd or microSD card.

[Idnarn]

(11-10-2024 06:41 PM)ajay_m Wrote:  The reader modules cost about £5.

You may want to petition Moravia to include NFC in a future version of the calculator itself. They may be able to support it without modifying the ROM that is emulated. No other device would be required.

I don't know how much power it would require though, whether it would be a drain on the cells.

Another option may be a barcode scanner (such as QR code). But that would mean integrating a camera module and its increased power consumption.

Micro SD cards are also an option.

[John Keith]

I don't think that either NFC readers nor SD cards are feasible for a device powered by coin cells. A USB port would make the most sense.

[Idnarn]

(11-12-2024 12:32 PM)John Keith Wrote:  I don't think that either NFC readers nor SD cards are feasible for a device powered by coin cells. A USB port would make the most sense.

In that case it already has enough. If it needs a PC, what the current 15C CE device has is not lacking. There's a software gap, but I expect it'll be closed soon so one can easily write, save, load, and transfer programs to it.

See for some basic components of a workflow: https://www.hpmuseum.org/forum/thread-22525.html

[battlecoder]

(11-12-2024 12:32 PM)John Keith Wrote:  I don't think that either NFC readers nor SD cards are feasible for a device powered by coin cells. A USB port would make the most sense.

I was thinking more of a "dock" that uses AA or AAA batteries, or maybe a 18650 / Lipo pack. I would love that.

From what I've seen the VoyagerSave app uses HID commands to load and save states. There are microcontrollers that can absolutely run a crude USB Host implementation for HID devices. The dock could have the pogo pins at the base, much like old handheld craddles.

[AnnoyedOne]

(11-12-2024 03:19 PM)battlecoder Wrote:  I was thinking more of a "dock"...

Not a dock/cradle but it does make the calculator easier to use with a USB cable attached.

https://www.hpmuseum.org/forum/thread-22441.html

A1

[battlecoder]

(11-12-2024 03:23 PM)AnnoyedOne Wrote:  

(11-12-2024 03:19 PM)battlecoder Wrote:  I was thinking more of a "dock"...

Not a dock/cradle but it does make the calculator easier to use with a USB cable attached.

https://www.hpmuseum.org/forum/thread-22441.html

A1

Oh yeah, I saw that stand already. It's a great idea, and a fantastic project. Definitely the next best thing after a standalone cradle (which currently doesn't exist, sure, but it's technically feasible)

[ajay_m]

Well, you can purchase the little pogo pins
on Amazon. I had imagined 3d printing a plug and also 3d printing a replacement battery cover which would mount a micro usb socket wired back to the new plug.
Then you could obviously just plug in a usb cable without removing the battery cover.

[Divasson]

(11-12-2024 06:26 PM)ajay_m Wrote:  Well, you can purchase the little pogo pins
on Amazon. I had imagined 3d printing a plug and also 3d printing a replacement battery cover which would mount a micro usb socket wired back to the new plug.
Then you could obviously just plug in a usb cable without removing the battery cover.

I have 3D-drawn some examples based on our screwless door on Fusion 360 but the length of the pogo pins is too long to fit properly. I am discussing with the cable factory for possible solutions.

[ajay_m]

I would love an STL for the screwless battery door if one is available. It would save an awful lot of faffing around. I can bring that into freecad and then do some Boolean operations on it to cut out space for a usb port I would think.of course space is tight but let's see....

[ajay_m]

I just ordered some 4mm high pogo pins for experimenting with. These are of course smaller than the standard 6mm ones If I can 3d print a small plug that is held in place by a modified cover assembly, it ought to be possible to fit in a micro usb socket. That would be a complete game changer I think in terms of convenience.

[ajay_m]

I will of course share anything if successful through instructables.