Building the Classic 1976 COSMAC "ELF" Microcomputer

********UPDATE August 2017:
I used the spare parts from this ELF build to make a another, duplicate, ELF computer, differing only in that the second one does not have the audio output jack, and uses only the single clock oscillator (does not have the alternate slow speed oscillator) for the 1802. This second computer was donated to the National Museum of Computing at Bletchley Park, England, and went on display in their vintage personal computer gallery at the end of July, 2017.

********UPDATE March 2017:
I have now published a complete set of plans for the ELF, downloadable from:
www.serpentwebsite.com/COSMAC_ELF_build_details.zip
and this includes a full user's manual, list of 1802 instructions, schematic, parts list, assembly diagram, etc; plus the Front Panel Express design file for the toggle switch panel.

The same set of ELF plans, and my ELF User's Manual, can also be downloaded from COSMACELF.COM ********

In early 1975, Popular Electronics magazine featured a cover article on the MITS "Altair 8800", an Intel 8080 based microcomputer that has become known as the first mass produced personal computer; it was very limited in its basic form, but expandable. And while expensive it was still much less costly than any other computer option at that time.

In August 1976, Popular Electronics had another cover article on an entry level personal computer, the COSMAC "ELF", based on the RCA 1802 microprocessor. RCA employee Joe Weisbecker helped to invent that processor, and he used his familiarity with the device to develop the ultra simple, very low cost, ELF microcomputer. It could be made by the magazine reader for roughly 10% the cost of an Altair 8800, and while not very useful by itself, it could potentially be expanded until it became useful. The ELF had very limited I/O and interface for the user, but by evolution it could be made to support a better display and keyboard, have more memory, interface with a video display, save and load programs using a cassette tape, and run operating systems/languages such as BASIC.

I had obtained an Altair, and had been interested in making the "cute" ELF, but never did. Now I have checked that item off my bucket list by building an authentic ELF from the information provided in the original magazine article. This video is a slide show of all the steps of making my ELF, and I have a brief video segment at the end that shows how the ELF's controls work, and I enter and demonstrate a simple program.

Видео Building the Classic 1976 COSMAC "ELF" Microcomputer канала youtuuba