FYP Topics     Introduction     Hardware     Software     Thanks     Further Developments   Hardware   The hardware for this project have four functions: Amplification Filtering Isolation Analog to Digital Conversion Amplification: Pre-Amplification is provided by an AD620 instrumentation amplifier. It has a programmable gain of up to 1000. This is ideal to amplify a signal ranging from 6 microvolts to 2 millivolts. It provides more than the required CMRR of 90dB (approx 110dB) and also high impedance 10Gohms. The gain will be chosen such that the output of the amplifier will be 1V/0.8mV. Filtering: Filtering will be performed by a combination of 3-pole low and high pass butterworth filters. The filtering will remove unwanted frequencies below 20Hz and above 400Hz. The signal range is between 0-400Hz but when the motor units fire they generate a signal below the 20Hz range. These signals are unwanted noise, therefore they are filtered out. Any frequencies above 400Hz do not contribute to the signal so they should be filtered out. Isolation: For the patients safety, the preamp and filter units will be isolated from the PC via a linear feedback isolation utilizing two IL300 optoisolators. The optoisolator provides linear isolation for inputs up to 1v. It can isolate up-to 7500vac rms. This is sufficient for the task at hand. After the hardware was developed I was informed that though the device can isolate 7.5kV, a discharge of that magnitude would jump across the pins instead of passing through the device. This isolation may not be necessary due to the use of the sound card. ADC: The analog to digital conversion will be performed by a 16 bit Sound Card in the PC. Many of todays computers have multimedia capabilities. Hardware Ideas   If the sound card provided adequate isolation, there would be no need for a separate isolation section, thus the amplification and filtering could be contained on a single board. With the use of a supply inverter, one battery could supply all the power required. This would reduce cost and more importantly, weight.