What should I build next for the Cosmac Elf II?

[rubber_jonnie]

So there are a few things I'm considering adding to the Cosmac Elf II, so I thought I'd put it to the vote since it's election day here in the UK:)

First up is the Hyperboard 2:

Hyperboard-Rev-2.0.jpeg (233.13 KiB) Viewed 882 times

The Hyperboard is a modern take on the Netronics ELF II Giant Board which includes additional RAM and EEPROM, input/output ports and serial connections with 32KB RAM / 32KB EPROM, CD1852 Byte-Wide Input/Output Ports, CD1854 UART, Cassette IN/OUT with proto area. The board was slightly revised in 2026 to add the ability to reserve/allocate address space on the address bus for use with add-on boards that have their own boot loading software on board, like the Netronics BASIC/MATH/ROM board.

Then we have STG ELF 2K Disk for ELF II Card:

IMG_0655.jpeg (373.79 KiB) Viewed 882 times

Uses Spare Time Gizmos ELF 2K Firmware to add a Compact Flash Card "Hard Disk" to use with the ELF/OS Disk Operating System. Provides 32KB RAM / 32KB EPROM, 16C450 UART, Serial Communications with FTDI connections, USB FT232RL device, IDE connection, CF Card socket and Real Time Clock chip.

The Elf II SD card:

Screenshot 2026-05-07 at 09.51.27.png (2.67 MiB) Viewed 882 times

With 128K RAM, 32K EEPROM, TTL and Serial terminal connections and an SD Card for storage, the ELF II SD Card board provides the electronics and software to turn your AVI ELF II into a powerful RCA VIP compatible machine that is capable of reading, loading and running your software library of VIP and Chip8 programs just like the original RCA VIP.

Note: For full VIP compatibility, the VIP Keyboard for ELF II is required. Because of this it's my least favourite option, however the keyboard isn't 100% required, though it may also be necessary for using Basic, so if I need it I'll build it.

Last but by no means least is the AVI Reproduction Full BASIC Math/ROM Card.

AVIELF2FullBASICMathROM-pic.png (640.06 KiB) Viewed 882 times

The AVI Full BASIC Math/ROM Card is reproduction of the board that was made available for the Netronics ELF II.

I will say that personally I would prefer either the Hyperboard II or the STG ELF 2K Disk, but I will put it to the vote and abide by the results!!!

Let me know what you want to see

Please note that you won't be able to change your vote later (Just like a real election) so think carefully about what you vote for.

I will run the poll until the end of May, that way I can get the PCBs ordered when I get back from my holidays at the end of the month

[PhilC]

It would be the Elf 2k disc for me. You'll need it to load and save all the stuff that the other cards need.

[rubber_jonnie]

It would be the Elf 2k disc for me. You'll need it to load and save all the stuff that the other cards need.

2 votes for that so far.

[rubber_jonnie]

So, I'm back from holidays tomorrow so the order is in for the Elf 2k Disk board as voted for by you lovely people.

Looking forwards to an interesting build, plus by then I should have at least one working CDP1861 built too

[HigashiJun]

That wiIl be a nice add-on for sure !

[rubber_jonnie]

That wiIl be a nice add-on for sure !

Should definitely enhance it's capabilities.

[rubber_jonnie]

Well, the PCBs for the Elf 2k Disk arrived today

And they have proved the sockets I bought, so they'll be getting fully soldered in

More pics tomorrow.

[rubber_jonnie]

As promised, photos:

The board itself:

IMG20260602085835.jpg (345.68 KiB) Viewed 669 times

And fitted in one of the expansion slots:

IMG20260602085849.jpg (323.96 KiB) Viewed 669 times

It'll be a little while before I can get to this though as there are almost as many components as the Cosmac Elf II itself and I'm confident I won't have a lot of them, so I need to get a build box on the go.

[HigashiJun]

Have fun populating it !

[rubber_jonnie]

Have fun populating it !

Should be a bit easier than your Archimedes