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Memorandum DATE: 26 September 2015 TO: Professor Timothy F. Wheeler FROM: Nasser Aljadeed SUBJECT: EE300W Lab 2 Status Report The main task for Lab 2 is to design an Optical Theremin, a musical instrument that can be played without physical contact. It functions by using two photodiodes as light detectors that detect light reaching the circuit, allowing users to control the frequency pitch and volume that the theremin produces based on light intensity. During the first week of lab 2, Greg and I designed a circuitry to measure the leakage current from the photodiode using a TL074 op-amp that functions as a transimpedance amplifier. The transimpedance amplifier converts the diode current into a negative signal voltage, whose magnitude will control either the frequency or volume tone of the theremin. During the second week of lab 2, our task was to design an auto-tuned optical theremin. Before approaching this task, we started the LabView code to process the detector’s signal for controlling the frequency and amplitude of the theremin. We acquired the outputs of both detector circuit’s signals with the DAQ assistant and set up the DAQ assistant to receive signals presented to the myDAQ’s analog input ports (ai0, ai1). We still have to design two VI blocks, one for the frequency and the other fore amplitude. By using equations: "(sin - Lmin Lmax-Lmin)(f – f ) + f ” and “(sin max min min Lmin Lmax-Lmin)" for the frequency and amplitude VI, respectively, we are able to normalize the input to set the max and min light levels for the light detector and coerce the signal to remain within the range of normalized values. Before lab 2 next week, Greg and I will meet to work on the rest of the LabVIEW code, including finishing off the frequency VI and amplitude VI using both equations above. We will then add an auto-tune feature to our theremin design that tunes the pitch to tones in the equal-tempered scale within the human hearing range.