Live demonstration: Towards an ultra low power on-board processor for Tongue Drive System

Tongue Drive System (TDS) is a new unobtrusive, wireless, and wearable assistive device that allows for real time tracking of the voluntary tongue motion in the oral space for communication, control, and navigation applications. The latest TDS prototype appears as a wireless headphone and has been tested in several human subject trials. Producing a smaller and more stable version of the TDS requires placing a considerable restraint on the battery size, and consequently requiring a considerable reduction in its power consumption to operate over an extended period of two days on a single charge. To reduce this power consumption, we have implemented an ultra low power local processor for the TDS that performs all signal processing on the transmitter side, following the sensors. Assuming the TDS user is on average issuing one command/second, implementing the computational engine reduces the data volume that needs to be wirelessly transmitted to a PC or smartphone by a factor of 1500x, from 12 kbit/s to 8 bit/s [1-2]. The design is implemented on an ultra low power IGLOO nano FPGA and is tested on an AGLN250 prototype board using four external LSM303D 3-axis magnetometers and a Texas Instruments CC2540 Bluetooth transceiver, as seen in Fig. 1-a. According to our post place-and-route results, implementing the processor on the FPGA drops the power consumption by 27%. This work presents the demonstration of first implementation of the proposed onboard FPGA-based processor for TDS. This demonstration is based on our earlier published work in the special edition of Biomedical Circuits in the IEEE Transactions on Circuits and Systems II [1].