I have constructed an op-amp based circuit to measure a biosignal known as Electromyogram or EMG. I have attached the image of the output signal measured from an oscilloscope. EMG signal is basically a measurement of electric potential generated due to muscle contraction. In the attached figure, the portions of the signal which have higher amplitude occur when Im flexing my forearm muscles. Im flexing my muscles three times, and each time i flex my muscles the amplitude of the signal increases.
Now im interested to digitize this signal by inputting this signal to an ADC pin of an arduino board and transmitting these signals wirelessly (using a pair of xbee tranceivers) to a computer for further signal processing. However this signal has both positive and negative components. Should I ‘offset’ the signal (using additional op-amp circuits) so that the signal falls within the 0-5V range? How should I go about to transmit this signal wirelessly?
Ive also attached the circuit i have constructed. The outputs of these circuits will be sent as inputs to the arduino pins.
EMG_circuit.pdf (296 KB)