I have also been fighting this problem. Apparently the software has a fixed range and you must adjust your camera-to-grating spacing to "fit" your desired spectrum width into what the software expects, as the adjustment capability of the software is very limited. If you can't do this, the colors will not match the correct wavelengths on the screen. The actual spectrum scale can be adjusted over a small range by dragging the calibration points one way or the other. This allows doing some "matching" of your input spectrum to the software, but the colors will not match unless the input range is what the software originally was designed for. I think the engineer guy (below) is finished with the software and doesn't want to continue developing it. Another problem is that most webcams have AGC which adjusts the "gain" of the sensor to keep the signals in the linear range of the sensor. This makes it difficult to compare absolute amplitude (brightness) of the peaks since they will be compressed as they get larger while smaller peaks will be left alone. If Mr. Engineer below would be gracious and release the software source into open-source other developers would continue to upgrade it to add more functionality.

@@glasslinger if you goto Theremino download v2.9 of spectrometer with source get copy of Visual Studio 2017 it will uprgade and away you go let me know how you go

It's free

ja

Amazing tool, very useful for young scientists. Congratulations and thanks for you and your company.

I build it and it works great, I would like to measure the reduction of UV light through some materials, but it is auto adjusting. It would be great to be able to say if UV radiation was reduced by X Percent, is there a way to measure this somehow?

The calibration procedure is not complete. Douse not take in the consideration the color spectrum sensitivity of the webcam. Cud be done by measuring an incandescent ball light and render the curve of the spectrum as a reference for the amplitude - color calibration. This is why perhaps the "CodeDocu" guy uses a monochrome camera.

You rock bro. I'm building a UV spectrometer now based on a youtube build - just want to say thank you.

Can it measure the change in intensity consistently? It does not have to be accurate- just consistent.