NDIRsim app

The NDIRsim app is a browser-based simulation tool for the development and optimization of NDIR sensors - installation and administrator rights are not required. Based on the Beer-Lambert law and the HITRAN database, it enables realistic modeling of gases as well as real-world conditions such as pressure and temperature.

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For spectrum simulation, you can select the desired wavelength or wavenumber range and define the resolution via sampling points - depending on your needs, either for fast calculations or highly detailed spectral analyses. Filter parameters such as CWL (or alternatively CWN), HBW, and transmission can be applied directly to the calculated line spectrum and evaluated immediately.

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This allows you to visually verify whether the filter bandwidth is optimally chosen, whether there is sufficient baseline on both sides of the target absorption band, and whether potential interfering gases need to be considered.

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In addition, NDIRsim simulates optical path lengths and concentration ranges to derive absorption curves and calibration points - displaying absorption (%) as a function of concentration to enable targeted optimization of the measurement range.

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For a quick start, predefined Micro-Hybrid standard IR filters are available and can be used directly in the simulation.

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To support realistic sensor design studies, NDIRsim allows you to define the maximum concentration of your target gas in vol.-% and convert common ppm values using a simple reference formula. This way, you can reliably identify suitable spectral ranges for measurement and reference channels.

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A comprehensive tutorial for the app can be found here: NDIRsim tutorial