A mechanical computer may not seem all that practical in today's electronics-driven world. That didn't stop Chris Fenton from building one for himself.

Chris, an electrical engineer by trade, made the Turbo Entabulator out of his love of computers--new and old--and an interest in how they work. Chris wanted to see how basic of a computer you could make while  still being able to call it a computer.

The Entabulator runs the classic Fibonacci series, punching out the mathematical sequence on cards.  Most importantly, though, the computer is purely mechanical--you won't find any electronic components. As a result, the Turbo Entabulator requires some manual labor--you have to turn a crank for it to run. Chris produced almost all the parts with his MakerBot 3D printer, the only electronic know-how needed.

As Chris puts it:

"We have such amazing tools available to hobbyists these days, a single person can explore ideas that used to require teams of people and factories worth of equipment. Without a 3D printer, I have nowhere near the skill, time or resources required to build something like the Turbo Entabulator. Now I have a Makerbot on my desk though, and I can design and build a mechanical computer in a few months of fiddling!"

As you can imagine, the Turbo Entabulator wasn't the easiest project to create.Chris has to write the Entabulator's software from scratch. The hardware wasn't easy to assemble, either, since it involved numerous small, intricate parts. However, it was also a new learning experience for Chris.

"The mechanical counters [were fiddly]," Chris explains. "I had extremely little experience designing anything with moving parts prior to this project. The counters don't always 'snap' into position, and can wind up reading '7 3/4' instead of '8', which can jam up the machine when you go to process the next instruction.

He continues, "Mechanical engineering requires a much different mindset than what needed for designing digital logic for a computer."

You can learn more about the individual parts of the Turbo Entabulator and the program needed to determine the sequence on Chris' blog. He's also uploaded the files to Thingiverse, so you can make one  yourself.