Jim MacArthur built this incredible Turing machine using wood and scrap metal, which he demonstrated at MakerFaire UK in Newcastle. It is entirely mechanical, except for the electric motor used to drive it. He writes:
This is a mechanical universal Turing machine (given an infinite track). It uses ball bearings as its memory and has no electrical components, other than a small motor used to drive it. This is a quick overview video filmed at Maker Faire UK 2011.
The machine is a close physical model of the theoretical Turing machine – a device first described by Alan Turing in 1937 as a thought experiment to understand the limits of mechanical computation. According to the theory, the machine performs calculations using a set of rules to manipulate symbols on an infinite strip of tape.
Instead of using tape, this machine’s memory uses ball bearings placed on a steel grid. A ball can represent one of five different symbols based on its position on the grid. The machine reads and writes data by repositioning the balls into different cells. It does this by moving along the grid, lifting ball bearings with magnets and then depositing them into a new position based on a set of rules.
A true Turing machine requires an infinite track or tape to run on but according to MacArthur, his machine is as close as you can get to a physical replica. It has no practical computing applications and would take months to add a few numbers together but MacArthur says it was fun to build. “Since you can see this computer working, it could be useful for educational purposes,” he says.
Beautiful work, Jim!
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.