  Multiarticulate bionic arms are now capable of mimicking the endogenous
movements of the human hand. 3D-printing has reduced the cost of prosthetic
hands themselves, but there is currently no low-cost alternative to dexterous
electromyographic (EMG) control systems. To address this need, we developed an
inexpensive (~$675) and portable EMG control system by integrating low-cost
microcontrollers with an EMG acquisition device. We validated signal
acquisition by comparing the signal-to-noise ratio (SNR) of our system with
that of a high-end research-grade system. We also demonstrate the ability to
use the low-cost control system for proportional and independent control of
various prosthetic hands in real-time. We found that the SNR of the low-cost
control system was statistically no worse than 44% of the SNR of a
research-grade control system. The RMSEs of predicted hand movements (from a
modified Kalman filter) were typically a few percent better than, and not more
than 6% worse than, RMSEs of a research-grade system for up to six degrees of
freedom when only relatively few (six) EMG electrodes were used. However, RMSEs
were generally higher than RMSEs of research-grade systems that utilize
considerably more (32) EMG electrodes, guiding future work towards increasing
electrode count. Successful instantiation of this low-cost control system
constitutes an important step towards the commercialization and wide-spread
availability of dexterous bionic hands.
