Lego Turing machine

Some more wonderments in honor of the Alan Turing centenary: Jeroen van den Bos and Davy Landman from the Centrum Wiskunde & Informatica in Amsterdam have created a working Turing machine out of Lego. It is both inspired and an inspiration:

Our LEGO Turing machine uses a tape based on a classic interpretation of computer memory: switches. Additionally, it uses a light sensor to determine the value of a switch: if the switch is on, the sensor will see the black colour of the switch's surface. But if it is turned off, the sensor will see the white colour of the LEGO beam, making it possible to distinguish between the states. Finally, a rotating beam mounted above the tape can flip the switch in both directions.

Alan Turing's original model has an infinite tape, but LEGO had a slight problem supplying infinite bricks. So we chose to fix our tape size to 32 positions.

A Turing Machine built using LEGO In honor of the Alan Turing year 2012



  1. It looks like it would be easy enough to have the “read” head in a fix mount or only have it move when a bit is flipped…

    Still it is interesting seeing how “new” technology recreates its ancestor.

  2. FTFV: These are all the components needed to describe any operation your computer can execute.

    I can’t locate it on my new computer, but somewhere on my previous computer there was a “smoke release” switch that activated when lightning struck. Seems to be missing from this model. Otherwise, great machine!

    Looking forward to the Lego Monks website. (Perhaps to be founded by someone named “Larry Brick”?)

  3. Lego Turing machine has made all previous lego models obsolete.   All hail the new plastic!

  4. That sample the music starts with: isn’t that from Raymond Scott? Or some other synth pioneer of that time? I know it, but can’t remember!

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