How Hard Can You Punch the PunchBot?

One question had always bothered Russell Munro.

“I have been practicing various Martial Arts styles for over 15 years and have always been curious about one particularly primitive part of my pugilist pastime: how hard I can punch?” Munro asked. “More than that I want to know ‘pound for pound’ is it all about size or does the skill factor come into it?”

Munro decided to answer the question quantitatively, by building a device that measured the force of his strikes. Unsatisfied with existing devices, he built his own prototype to measure the power of a punch in watts.

He built the PunchBot’s frame out of mild steel and aluminum. For the electronics, he opted to use an optical rotary encoder, due to its high degree of accuracy, which he connected to an Arduino Uno that measures the tiny increments of time between each angle. A laptop then crunches the numbers and calculates the power of the impact.

Munro initially considered using an accelerometer, but ultimately decided that if the bag was heavy enough to ensure accuracy, it could put users in danger of breaking bones in their hands.

“I wanted a way to measure striking force,” Munro said. “I wanted a way for students at my club to accurately measure their performance over many years.”

Munro entered his device in the Pitch Your Prototype Challenge — a collaboration between Make: magazine and Cornell University — with the goal of digging up promising prototypes from the Maker community. If he wins the contest, he says, he’ll use the capital to bring the PunchBot to market as a premium device for fitness clubs. He also hopes that the visibility of the contest might help him find a business partner.

There’s now less than a month left to submit your own project to the Pitch Your Prototype Challenge. The individual or team that wins the challenge will be awarded $5,000 and have the opportunity to appear onstage at MakerCon New York.

Visit this page to view the full contest rules to Pitch Your Prototype, vote for your favorite project or submit your own.

If Munro wins, he intends to launch a PunchBot website so that students can compete with each other to throw the hardest blow. See below for a closeup of the PunchBot and some early concept sketches.