Robert Sheppard's Elf

The photos below show a beautiful hand-wired modular Elf system designed and built by Robert Sheppard.

From Robert: “I was delighted to chance across the COSMAC ELF web site as I built an Elf around 1977, very soon after the first Popular Electronics article appeared. A kit of parts was obtained from Quest Electronics in Santa Clara, but by the time it had arrived I had decided on a very different layout for the construction. Flexibility and expansion potential were to be the keynotes. Accordingly the basic Elf circuitry was built on a single 43 way edge connector plug-in vector board with the two digit hex display piggy-backed on top. All the CDP1802 signals were brought directly to the edge connectors for future expansion. Later the hex display was removed and assembled on a separate board together with a 7-segment led address display. Provision for a total of ten  plug-in boards was made. The toggle switches were assembled as a separate unit which plugged into the other end of the CPU board.

“Remarkably the original Elf worked straight away and gave much pleasure and education to my 10 year old son and to me. I can think of no better way to learn the basics of machine code programming for wider application later. Nevertheless we were soon reaching the limits of the basic Elf, and the bus slots started to fill with memory (RAM and later EPROM), hex keyboard driver, 1861 and 1864 display boards, printer and ASCII keyboard drivers. All ten slots were soon filled and towards the end of its working life a Quest Gremlin graphic display board was finally piggy backed on the right hand side. The complete Elf microcomputer as it was when finally pensioned off is shown in the last photographs.

“The Elf eventually gave way to a similarly conceived S100 bus DIY computer. This used the much faster Z80 8 bit microprocessor, ran full Basic, and considerably widened the scope for programming.

Stunning work!

© Dave Ruske 2001-2017, except where noted