Students build replica of Turing machine

by Barbra Gottschalk | Communications and Community Outreach Office

In 1936, Alan Turing devised a theoretical model for mathematical calculation. He described a machine that could calculate anything regardless of complexity. Controlled by simple rules, Turing's machine reads and changes symbols in a line of squares (called a "cell"), modifying the properties of each cell, writing a new cell, and then moving the line of cells (called a "tape") to the left or right. From these basic concepts came the most sophisticated computers of today.

A team of Lincoln Laboratory scientists helped two students build a replica of a Turing machine—a project that will help the high-school seniors from the Community Charter School of Cambridge satisfy an internship requirement and will result in a new exhibit at Lincoln Laboratory.

Interns build Turing machine At the Senior Internship Exhibition Night at Google Cambridge, Community Charter School of Cambridge students Kyania Burke and Trevon Bennett (center) explained the building process used to create the Turing machine replica. They are flanked by their Lincoln Laboratory mentors, Timothy Greer (left), Chad Spensky (right), and Benjamin Nahill (far right), who helped the students approach how to build their Turing machine.

This particular Turing machine is being implemented in a more modern form. The design uses 35mm film as memory, on which bits are physically written and read with marker and camera respectively, to control the evolution-of-a-state machine—a design that fulfills Turing's requirements for arbitrary computation. During their internship, the students worked at the Beaver Works Center to develop embedded microcontrollers, numerous motors and sensors, and code to control the machine. The project exposed the students to good software engineering practices, machining technologies, 3D printing, and general product development.

Chad Spensky of the Cyber System Assessments Group, Benjamin Nahill of the Secure Resilient Systems and Technology Group, Stuart Baker of the Control Systems Engineering Group, Timothy Greer of the Intelligence and Decision Technologies Group, and Jack Lepird of the Surveillance Systems Group served as mentors, teaching Trevon Bennett and Kyania Burke basic electrical engineering, mathematical concepts, and product development.  Greer felt his first foray into mentoring was successful. He said, "It was a great pleasure to help instill the spirit of engineering in my mentees. Making this machine was pretty darn cool!"

Bennett appreciated the guidance from his mentors, saying, "While none of us had ever built one of these machines, the mentors were able to use their prior experience to come up with ideas and direct us through the process. We were able to add our ideas as well."

After learning how to work with Python programming language, Raspberry Pi single-board computers, Arduino electronic prototyping platform, and machine tools, both students enjoyed the building phase of the project. Burke said, "I learned how to do something that I had never pictured myself doing. The project was challenging, but we always motivated each other, saying 'We got this!'"

The Turing machine was not intended as practical computing technology, but rather as a hypothetical device representing a computing machine—an idea which Bennett found appealing. He said, "I liked the idea of building something that was never supposed to be built. The Turing machine was initially only a theoretical machine. Even its inventor never expected to build one! That idea is pretty cool to me."

Through this 3-month internship, the students practiced real-world skills and gained insight to a possible career path. Bennett said, "I'm going to college for computer engineering, so this experience coding and building will be invaluable to me in the very near future." He added, "This has cemented my ambition to be an engineer."

Plans are underway to continue working on the project to deploy a polished version of the machine at Lincoln Laboratory as a long-term exhibit honoring the late Alan Turing.


Posted July 2015


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