Wireless biopotential signals acquisition system

Abstract

In this paper, we present a low power wireless system based on a MSP430 based system-on-chip for biopotential signals acquisition. The system is capable of recording up to 12 ksps from up to 4 channels with independent gain and a 1 Hz to 5 kHz bandwidth. The gain for each channel may vary from 2.5 kV/V to 68 kV/V, being able to adapt signals in a range of 20 uV to 1 mV, to be digitalized in a 12 bits ADC. The system consists of 2 modules, which communicate wirelessly with each other via a 915 MHz link, with Minimum-shift keying (MSK) modulation. The communication reaches 358 kbps of transmission rate, with less than 2% of packets lost without retransmissions, within a 5 meters range. One of the modules is wired to a PC via a USB cable, reaching 921.6 kbps of transmission rate through UART protocol. The wired module is powered through the USB port, whereas the wireless module is powered with 2 AAA batteries, lasting for more than 24 hours of operation. A Matlab toolbox was developed in order to facilitate the data storage, system configuration as well as collected data analysis.