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“And yet it moves”
Batteries not included: Fifth Former makes himself the remote
By Mark Berghold
Losing the remote is not an uncommon occurrence in many homes, and mine is no exception. Our home’s five small devices, which control sound bar, DVR, TV, DVD, and VCR (those under 20 can look up this last item on the internet), seem to have been designed to autonomously make their way into the dark recesses between sofa cushions. Solutions to this modern annoyance include tethering the remotes to the sofa, or using a “Universal” remote, the Esperanto-speaking remote control. It was this problem which provided the genesis for one South Kent student’s Fall Term CFI project.
Many of the students in my Robotics CFI class use battery-operated controllers to move their vehicles around and to perform various tasks. Could one take the electrical signals from human muscle activity and use these to control a robot? I proposed such a challenge to 5th Former Shiqi Hu at the end of his fourth form year. We corresponded over the summer and, when school resumed in September, Shiqi began a crash course introduction to electromyography.
Electromyography is a diagnostic procedure used in the medical community to measure both nerve and muscle function. When nerve function may have been compromised due to trauma or disease, the signals which should travel between two points may no longer do so, or their strength or speed may diminish. In a healthy subject, the signals travel successfully and direct the muscle to contract to perform some physical task. Researchers are now able to restore mobility to some individuals with limb paralysis by capturing the appropriate nerve signals and, using complex software, sending enhanced electrical signals to prosthetics, mechanical analogs to the paralyzed limbs. It is at this intersection of computer programming, engineering, and biology that many inventors are finding fertile ground. Dean Kamen, Segway’s developer, has developed the DEKA Arm, an advanced prosthetic limb which its inventor, in a nod to Star Wars’ Skywalker, has dubbed “Luke”.2 “Dextra,” a bionic hand developed by William Craelius, professor of Biomedical Engineering at Rutgers, is another example of the kind of breakthrough which is certain to be enhanced as the technology is improved and costs come down.3
Building the robot was easy for Shiqi. His greatest challenges in the project were to eliminate the noise in the electrical signals picked up by the electrodes attached to his forearm, and to determine the correct threshold to then transmit an RF signal to the robot’s receiver. Even at rest, Shiqi’s muscles generate some activity; how should the software filter out this noise from the “human remote,” and at what point should the software determine that muscle activity should be interpreted as a command to move the robot forward?
With the sage counsel of my SKS MakerSpace colleague, Seth Mittag, Shiqi built his transmitter and receiver using the Open Source “Arduino” platform. After several software iterations, he eventually resolved the signal-noise issue and performed some successful tests prior to his scheduled, public demonstration.
At School Assembly in the Schoolhouse, on the final day of the Fall Term, Shiqi prepared his demonstration for the community. Shiqi rolled up his sleeve to reveal the electrodes fastened to his skin. A brief introduction to the project was made and, before a hushed audience, Shiqi made a fist.
And nothing happened.
Another flex. And nothing. Students politely applauded and were then dismissed for First Period. Shiqi was baffled and continued his test while his peers filed out of the room. And then his robot lurched forward. More students left for class, and the robot now consistently responded to Shiqi’s muscle command. Shiqi concluded that cell phone interference and not the A.I. equivalent of stage fright had prevented the robot from receiving his signals in the previously packed room. Dozens of pocketed, but active, cell phones had created enough RF chatter to drown out the one voice that mattered.
A few days later Shiqi invited a small group of people to witness another demonstration. It went off without a hitch. Shiqi was asked how he felt about his successful demonstration. With characteristic humility, and in keeping with the high bar he sets for himself, he responded, “It worked OK, but I wish the cell phone interference had not been such a problem.” Like many of the obstacles Shiqi faced during the project, this one may be addressed after he returns from his semester at the prestigious Maine Coast Semester School at Chewonki in a few months. “Mr. Berghold, when I get back, perhaps I can give the robot an IP address, and I can use my muscle’s electrical activity to control it over the School network?” I told him that this would be a great extension to his fine work and offered him a congratulatory handshake. The electrodes, still connected to his forearm, registered the handshake, and his robot, as if in tacit acknowledgment, responded by lurching forward on the floor at our feet.
Read more great articles from South Kent School's Center for Innovation in The Seed.
1“Eppur Si Muove” was the (perhaps apocryphal) utterance of Galileo Galilei following his forced recanting of geocentrism.
2From Star Wars to Real Life: New Prosthesis Transforms Lives
3Inventor Of Artificial Hand Sees “Bionic” Replacement Parts Becoming More Human