Operating Conditions for Performance Improvement of Paired Emitter Detector Diode in Optical Measurements Based on Photocapacitance Discharge

The paired emitter detector diode (PEDD) configuration has been applied as an effective option for the implementation of optical measurements systems, since this scheme can be easily implemented in a microcontroller and with a reduced number of components. In this work, an evaluation of the effect on the performance of the measurement system based on photocapacitance discharge of PEDD was performed by modifying the clock frequency of microcontroller, and current supply of emitter LED for light intensity control. These experiments were carried out in turbidity measurement tasks in reference standard samples, and in estimation of biomass concentration in liquid suspensions of the microalgae Spirulina platensis. The results obtained indicates that the sensitivity of the measurement system depends on the light intensity of the LED emitter, as well as the accuracy of the readings is determined by the clock frequency of the microcontroller and suggest that these shall be considered for measurement system based in PEDD configuration.