Mechanical arm wrestling demonstrates muscles’ electrical signals for local middle school students and mentors

By Nick Holden

On April 5, dozens of local middle school students stuck electrodes to their arms and observed the power of the electrical signals that travel through their muscles. The activity was part of the Office of Engineering Outreach Programs’ Middle School Mentoring Program, which pairs undergraduate and graduate mentors with middle school students from Boston, Cambridge and Lawrence, MA.

In the activity, developed by the NSF Engineering Research Center for Sensorimotor Neural Engineering – a partnership between MIT, the University of Washington and San Diego State University, among other institutions – electrical signals from the students’ muscles, captured by electrodes, controlled motors in two mechanical arms. Together, those two mechanical arms formed a simulated arm-wrestling game called WrestleBrainia 3000, in which students competed to pin their opponents by generating stronger electrical signals.

Before entering the WrestleBrainia ring, the students and their mentors tested a simpler version of the system that used the electrical signals from their muscles to control a single motor. They experimented with sensor placement and arm movement to determine the effects of different variables on the speed of the motor. At the end of the activity, the students shared out their findings to their peers and mentors.

MIT Professor Joel Voldman led the activity, introduced the students to the field of sensorimotor neural engineering, and showed a real-world application in a 60 Minutes clip featuring an amputee who could control a robotic arm through electrodes attached to her head.