Theremino Spectrometer

Simple Plug and Play USB camera, easily calbirate range of light diffraction spectrum range and see live light spectrum.

• Save image
• Save plot (as image and as data)

This application is written specifically to derive the best possible features from a spectrometer based on Webcam. If the operator knows his instrument and keeps the measurement conditions within the tolerable range, it can save a few thousand Euro and get the same results you would get with professional tools.

The weaknesses of a spectrometer based on webcam are:

• Dynamics Limited. You must be familiar with the instrument and use the right amount of light and appropriate exposure settings. If the light and the sensitivity is too high, they appear artifacts that distort the spectrum. If they are too low, the lower rows disappear.
• Strong dependence on the characteristics of the WebCam. With a few WebCam results are much better than with others. Some drivers may be completely unsuitable and even color settings and sensitivity can cause significant variations in the quality of the measurements.
• Accuracy and resolution limited. The resolution of the camera and the non-linearity caused by the deflection grating and by the objective lens, limits the accuracy to about one nanometer.
• Only wavelengths can be measured, not the amount of light. The Webcam (and all cameras) have a response not linear so quantitative measurements are impossible. You can not measure the amount of light, but only appreciate relative and approximated differences.

However, the features are good for teaching and for small laboratories.