In Allison’s class computational letterform and layouts, I learned Marble Adding Machine by Matthias Wandel and was impressed by it. It’s such an elegant and concise way to show how computation and binary works. So I’d like to make a one as the final project for Intro to Fab.

Prototype V1 and V2 for one bit, fabricated from discarded materials

What is a marble adding machine

It’s basically a mechanical calculator, or mechanical computer in a border way. Common types of mechanical calculator are Chinese Abacus (Suanpan) and Pascaline.

Chinese Abacus

Pascaline

Here is the one created by Matthias Wandel and a video show how it works.

Marble Adding Machine by Matthias Wandel

The core idea is to use one rocker to represent two states and use marbles to flip the rockers between the two states, thereby compute.

Ideation

At first, I wanted to just create this binary marble adding machine, but I found it less challenge and interesting, since the plan for this machine is open sourced and binary machine is not new.

Because I can’t think a way to optimize this binary machine (everything looks so perfect), so I decided to make it ternary (3 base). Here are some design goals:

• Only use marble to drive this machine.
• Don’t use complex mechanism.
• Make the size manageable.
• The calculation should be stable.

Challenge

It’s extremely hard to design a simple structure to represent three states. Firstly, I wanted to design a rocker with three states, but it’s so hard to make it move precisely and circularly. So I think maybe I can use two rockers but exclude one state from the four states. This is still hard but doable.

T-MAM V1

After comparing with different solutions, I decided to use a gate to control it.