Christian has SMA (spinal muscular atrophy) and uses a motorized wheelchair and a staff of assistants to navigate his daily life. He was also an early backer during OpenBCI’s first Kickstarter campaign in 2013, and while I was working in the OpenBCI office he finally had the opportunity to come by for a visit. With relatively simple tools, we were able to work with Christian to quickly connect with muscles throughout his body and demonstrate how they could be used as additional “switches” or actuators for controlling other devices. After a few minutes of experimenting with his newfound, EMG-powered capabilities, Christian was already brainstorming how this would let him be more independent at home, or even better, fly a drone. BCI technology has a number of promising applications in the assistive technology space, and Intel’s ACAT team (the group behind Stephen Hawking’s communication system) has been experimenting with OpenBCI as a way to make their system more affordable and accessible.
My summer working with OpenBCI in NYC was also full of technical challenges. Incorporating PhysioHMD into what would become Galea required a lot of work on the mechanical/ergonomics issues, new PCBs designs, and new firmware. Working with devices that conform to the users' bodies is a special type of challenge because of the variation that exists across individuals. If our sensors don't have proper contact with the user, the signal degrades, and environmental noise creeps into the data.
Similarly, when developing a mixed-signal, multi-board setup, each additional board or sensor component introduces new opportunities for disturbances or noise to be introduced to the system. These challenges required us to iterate and embrace best practices early on to minimize cross-talk, reflection noise, and ground bounce issues. One specific challenge for Galea’s multi-board setup was figuring out how to deal with the digital and analog grounds. The return path can become a source of noise if not dealt with properly. How do you prevent current loops from being introduced to the system? In our case, we established a star ground configuration that allowed us to explore different ground setups and determine whether each ground plane should be continuous or connected by resistors, while still making sure that every signal trace has an adjacent return path. This configuration gave us much-needed flexibility to probe and test how our ground was working at different locations. This was one of many challenges we needed to solve because of the number of sensors and boards going into Galea.
Aaron Trocola, NYC
Sean Montgomery, Nevada
Ioannis Smannis, Mesolonghi, Greece
Eva Esteban, NYC
Andrey Parfenov, Moscow, Russia
Nitin Nair, NYC
Joe Artuso, NYC
Shirley Zhang, NYC
Richard Waltman, Louisiana