About Zusie

I amuse myself by constructing a computer almost entirely out of relays. Relays were used to construct computers well before vacuum tubes, transistors or integrated circuits were feasible for the task. The main inspiration is the machines by Konrad Zuse of the late 30s and early 40s.

Why relays? In addition to constituting an important historical link between the mechanical and electronic computers, relays are especially fun to work with since they

So all in all, relays require you to think in very new ways compared to normal solid-state devices.

The relays I use in the computer.

Quick feature list:

To build a relay computer, you clearly need a lot of relays. I had the good fortune of locating about 100 discarded telephone exchange circuit boards with about 15 four-and six pole relays on each board. I bought them at scrap prices and desoldered them with a hot-air gun and wound up with some 1500 excellent-quality relays.


Here is a block diagram of Zusie's architecture (click for larger version). It is a fairly regular CISC, microcoded architecture.

Instruction Set

Here are some terminology used below and in Zusie assembly code:

Here is a comprehensive list of Zusie instructions and mnemonics:

Fredrik Andersson - nablaman[at]nablaman.com
Back to Zuse home  |  Back to my home page