Design and development of microcontroller based photoacoustic spectrometer

Abstract

The paper describes the design and development of microcontroller based photoacoustic spectrometer (PAS). The photoacoustic (PA) cell designed for the present study is of Helmholtz resonator type with a provision to measure the sample behavior as a function of temperature. In this system, an electret microphone is employed to achieve high signal to noise ratio. The microphone compartment is isolated from the sample compartment to avoid the heating effect of the resistive electric microphone which detects the photoacoustic signal. A two stage preamplifier and tunable band-pass filter have been designed with a low noise op-amp LM308. C8051F060 microcontroller has been used to acquire and process the signal from photoacoustic cell. The frequency response of the cell is studied with carbon-black as a sample. The resonant frequency of cell was found at 330 Hz. The system is very compact and easy to carry the experiments. © 2012 IFSA.