As an undergraduate, Luis Villaran ’11 played guitar in a campus band, the Plagiarists. One problem all guitarists face is having their instruments go out of tune during a performance. Villaran, who was majoring in mechanical and aerospace engineering, decided to invent a robot that would keep his guitar in tune at all times, even while he is playing it.

The robot Villaran invented is a small box, about 4 inches by 6 inches, which sits atop the guitar, resting over the pegs. A wireless component nearby on the floor “hears” the notes the guitar makes and, if it senses that the guitar is out of tune, sends a signal to the box, which tightens the proper peg until the pitch is correct. 

It was essential that the device be lightweight and strong. Villaran designed it out of high-density polyethylene, which he ordered online and hand-milled in the mechanical engineering department’s workshop. He wrote the software that controls the device, and says he decided to try it first on a larger bass guitar, which requires a lot of torque to turn the ­tuning pegs.

“I thought it was a new idea,” Villaran says, “but I learned that it ­wasn’t.” Although it turns out that there are other automatic guitar tuners on the market, Villaran believes that his has several features that raise it above the competition. It is, he says, “performance ready”; in other words, it works while the guitar is being played, without the need to unplug the guitar and insert it into the tuner. It is also more mobile than other devices, and it could work with any type of guitar.

So far, Villaran is the only person using the robot, although his former Plagiarist bassist has given it a thumbs-up. Villaran is now studying product design at Stanford, where he hopes to continue designing software, applying some of the techniques he learned in the robotics program. “At Prince­ton,” he says, “they give you the tools.”