Development of a Preamplifier and a Wireless Surface EMG

The primary objective of this study was to develop a preamplifier and a wireless surface EMG of a noninvasive type. The limitations of the existing system include its large size and the necessity of a wire. Therefore, this study focused on the development of a preamplifier which includes three electrodes and a wireless EMG. The EMG described herein is comprised of a preamplifier including an electrode for the measurement of the EMG signal, a main amplifier for signal processing, an A/D converter, and a Bluetooth module for wireless communication. The developed EMG utilized a UART (Universal Asynchronous serial Receiver and Transmitter) and Bluetooth protocols for communication. The sampling frequency of this system is 1,024 Hz. The developed EMG signal has relatively favorable characteristics as compared with current commercially available EMG systems. In our power spectral density analysis, the EMG signal was distributed between approximately 70 Hz and 200 Hz, and between approximately 10 Hz and about 50 Hz.