Quick Start

Quick start guide.

This guide will show you how to use the basic functions of the app by analyzing the "example_spectrum.jpg" file provided. The screenshots below are from the program running on a Samsung Galaxy Tab 3. The spectrum was generated by a simple spectrometer made using a tube of lip balm.

Load Image

With the menu button, select File->Load New Image

Load

An example image has been provided, select it.

The image will come up in its own tab. The image shown is the first order spectrum of a typical household compact florescent light (CFL).

You can load as many images as you want, they will all go into their own tabs. [Multiple tabs only available in paid version]

Example Spectrum

Display Maximums and Intensities

To find the maximums of each line touch the button Max's

Maxs

You can also show the Total intensity and the Blue, Green, and Red components.

Below is the same image but only showing the color lines (pinch to zoom).

zoomed

You will notice that I was a little too close to the light source when I took this picture as I saturated my colors.

Note: from the intensity diagram, you can see that there are a number of other peaks and the maximum lines don't line up with all of them. This is because of the default settings for smoothing, minimum intensity, and range of consideration. The defaults are set to find the dominant maximums. You can set this to your preferences (see settings in user manual for more details).

Calibration

Once the maximums have been found, you can calibrate your system in order to find the wavelengths of each line. This entails choosing a number or maximums and telling the program what their wavelengths are. The CFL has well known wavelengths of which you will see the dominant ones listed.

Calibrate with the first blue line by touching this line, the calibration window will pop up.

calibrate 1

Choose the 405.4nm value, touch the first button and then touch "Ok".

Next touch the red line and the Calibration window appears again.

calibrate 2

Choose the 612.0nm value, touch the second button and then touch "Ok".

In this case, we will only need two lines for calibration because we have the center line included in the spectrum and I used a diffraction grating ruled at 360 lines/mm to take the picture (which is the default). If you did not know your diffraction grating size, you would have to use three lines for calibration (see calibration in the user manual)

To set the calibration, from the main menu select Calibrate->2 Line Calibration With Center

The system is now calibrated and you will see on the bottom row it will tell you the grating size and the angle of incidence of the light. (If you want, you can now remove the little calibration flags by selecting from the menu "Calibrate->Remove Calibration Lines".)

Once the system has been calibrated, touching on the lines will no longer bring up the calibration menu. If you wish to recalibrate, choose "menu Calibrate->Remove Calibration", then you may start the process again.

Viewing Line Wavelengths

Now that the system has been calibrated, you can see the wavelength of any line in your spectrum (as well as a list of elements that produce a wavelength in this range) by touching and releasing the line. Here we chose the third line and are showing all elements that emit at a wavelength within 0.5nm of this. The Ion: # is the ionization level of the element that emits here.

showing wave

(Note that I have this line listed above in the calibration box as 487.7nm, so even with my simple spectrometer
we have an accuracy better than 2nm. I bet you can do even better!)

We also have an option to generate a report for the whole spectrum. From the menu select Image->Generate Report. A pdf report for this spectrum will be created and will try to open in your default pdf reader. [Available only in paid version]

Moving forward:

Of course, it's not going be that useful to only be able to show the wavelengths of the spectrum you already know!

The idea is to load or take multiple images. Calibrate with a known source (the CFL is a good one because it has a number of easily distinguishable and known lines). Then you can determine the wavelengths of all the lines from the other images you have taken. You may either use your favorite camera and then load those images into the program or (in the paid version) you can use the camera function provided in this app.

Application Notes:
1. The camera has been tested on a Samsung Galaxy Tab 3 running Android 4.1.2 with no issues. It also ran well on stock Android 4.4. However, it crashed under Samsung's modified version of 4.4 for the Galaxy. At this point, while the matter is under investigation, consider the camera functionality experimental which may or may not work on your android version. [Camera available only in paid version]

2. On some versions of android, LightSpectra and LightSpectraLITE will not switch properly if you:
         - switch apps,
         - then press home,
         - then press the app again.
To guarantee that the program switches back properly, please use an app switcher instead.

Happy Spectruming!

Philip Weetman, 2014
Philip.Weetman@gmail.com

Camera Disclaimer [for paid version]
The camera part of this app is based on the QT example "declarative-camera" using QML. It is free to use provided the information below is attached in the documentation.

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License Disclaimer

LightSpectra and LightSpectraLITE are built using the open source version of Qt 5.3.1. 
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