IR Absorption Research

Embedded Electronics Systems





    This little device was built to test infrared (IR) absorption properties of various hydrocarbon fuels. There is a 1 inch deep well at the top of the cell with an IR sensor and emitter mounted on the sides a half inch from the bottom of the well. There is an RTD temperature sensor underneath the well and a heater array on the outside of the cell. The cell temperature is controlled by a PID loop. A fuel sample of fixed volume is put in the well and a vented cover placed on top. After a  procedure was developed that provided high reproducibility, the data from a variety of fuels was recorded.

    Because background heat is also an IR emitter, IR emitters have to be modulated to distinguish their output from the background noise. For this research, sensor output was digitally processed to provided a 'lock amp' and easy changes to filter changes. The signal processing was done with RDG&A's Digital Signal Box, a general purpose instrument used in the development of many projects.

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