Implementação de um sistema embarcado para Miofeedback

Abstract

Electromyography is a technique for the study and analysis of bioelectric phenomena that occur in the cell membranes of muscle fibers. Through this technique it is possible to diagnose a number of disorders and motor problems and also to analyze the behavior of muscles in various situations. The electromyographic (EMG) signal, resulting from the summation of Motor Unit Action Potential Trains (MUAPT s) of different muscle fibers innervated by the motor neurons, is captured and measured by a device called electromyography. With the advent of technology many electronic devices, especially in health care, have become portable and embedded as oximeters and electrocardiographs. The vast majority of electromyographic device is based on a communication with a computer, either RS-232 or USB via an interface in software, in which all processes necessaries are performed, and then saves the signal for further analysis. Thus the device, hardware, has a signal conditioning system and digitizing process for sending data to the computer. This makes the device user, i.e., physical therapists, doctors, dentists and others, to become dependent on an external device to view and process the signal. Few studies have been worrying to the fact of designing an EMG device that possessed all these traits so embedded and portable. Thus there is a lack of studies that aim this creation. In this context, the main motivation of this research is to create a prototype of a portable EMG biofeedback embedded in hardware. To do this it was created a professional printed circuit board, which contains the necessary instrumentation for acquisitioning, conditioning, digitalizing, viewing, processing, saving and also sending the EMG signal. The biofeedback for displaying this signal is provided by a Liquid Crystal Display - LCD using TFT (Thin-Film Transistor) technology, colored, touch-screen and 320x240 points. Further, as aid biofeedback, there is a bar graph with 10 LEDs for each acquisition channel in order to indicate the level of muscle activity. The system is battery-powered and has four channels of electromyography assets and a reference electrode. The results are satisfactory since it is the first version of the prototype, and the signal was conditioned satisfactorily with what was designed and also digitalized to show it on the LCD.