As a physics major undergraduate, I believe in theory of laboratory and practical experiments and physics. Laboratory courses and experiments provide practical results, usually more effectively help clarify concepts than lectures. However, because of the global popularity, we have not played the experimental class for more than a year.
Most experiments, especially in the last year of undergraduate physical courses, requires complex, complex and expensive instruments and equipment. However, in our course, the spectroscope experiment caused my attention. I decided to build a low-cost version using the materials that can be used by each family.
I also interested in computer science, so I decided to use the webcam to make a digital version of the spectrometer and create a program to analyze the results.
Continue to create your own DIY low cost spectrometer, if you like the project and decide to build your own version, let's put down your favorite and follow this page. I really want to see your own version, so please use "I do" to post your work.
Step 1: Spectrophotometer Theory Overview
The concept of spectroscopy is usually elaborated in this undergraduate physical course, but here is a brief description of the theory behind the spectroscopy and spectrometers.
The spectrometer is a clever instrument for measuring light characteristics. This allows scientists to use the instrument to perform a large number of experiments, such as determining the materials found in the objects used in daily lives or determining the elements found on the distant star and planets.
The basic concept of the spectrometer is to illuminate the "unknown" beam to the optical element, the optical element separates the beam in accordance with the wavelength present in the "unknown" beam. Each wavelength has a different deviation, so by measuring deviation, it is possible to determine the wavelength existing in the "unknown" beam, which may provide more information about the beam source, even if it originated from millions of kilometers.
Earlier, scientists use prisms to divide the beam into multiple components, and use rotating eyepieces to measure the angular deviation of each wavelength component. However, recently, the prism is replaced by a diffraction grating, and its effect is the same as the prism, and the eyepiece is connected to the computer's electronic photoreceptor array instead.
Step 2: Material required
This is a list of all components and parts required to make your own low cost spectrometer. All components should be seen everywhere and are easy to find, and you may have placed them at home.
Material:
cardboard
Black graphic paper
Old DVD disk
Razor
Camera
glue
Tape
The total cost of the project does not include the network camera is less than 5 US dollars.
Step 3: Building a housing component
The outer casing can be made using any type of box, but I decided to make one from the beginning to make it a perfect size of the webcam I am using. First measure the webcam:
high
width
Lens height
Make a box according to the following dimensions:
Length - 20 to 25 cm
Width - larger 2 cm than the width of the webcam
Height - 1 cm than the height of the webcam
According to the size, 6 faces of the box are depicted on a cardboard, and then cut the debris with a knife. Make a slot on the back, you can pass through the slot through the webcam cable and make a 2 cm x 1cm slot on the front of the camera lens height.
Use glue to stick all surfaces on a black chart paper, then cut paper along the border of the paperboard.
Note: Use pencil marking face to avoid confusion.
Step 4: Assembly housing
Be
Grab the bottom and two sides and place it in parallel. Use the tape to connect three parts together. Next, by ensuring the direction of the holding surface, the front and back is pasted using more tape.
The top is connected along a single edge so that we can use the top to open the housing as the hinge cover to prevent any adjustment in the future. To prevent any light from entering from top, cut some cardboards to slightly overlap.
The housing is peeked by one of the slots and ensures that there is no light into the box. Additional layer of electrical tape or any type of opaque rubber can be used to cover small gaps.
Step 5: Production of inlet slits
In order to make an inlet slit, one of the shaved blades is passed vertically to cover a portion of the gap. The second blade is attached to the first blade using a single sheet of paper, and a small gap is formed between the two blades. The second blade is pasted with tape and covers all gaps using the electrical tape to prevent any light from entering the housing.
Step 6: Making a diffraction grating
This step is the most critical part of the project. The diffraction grating is responsible for separating the beam according to the wavelength. One option is to purchase a diffraction grating directly. These usually can purchase online, with a price of about 4 to 5 dollars. Another option is to use an old DVD disc as a diffraction grating. Both provide similar results.
First use a scissors into the disc. When you cut your disk more deeply, you will notice that the disk consists of two layers, which will begin separate. The two layers are completely separated and discarded by half of the silver coating.
Since cut from the aftead half, then cut the edges into a square, form a small rectangle that is slightly larger than the lens width.
Next, use some glue to stick this piece on the lens. Be sure to use temporary glues to remove the diffraction grating when you want to reuse the webcam.
Note: A key step in the operation of the spectrometer is perpendicular to the concentric groove of the disc, that is, they need to be parallel to the slit. If they are not parallel to the slit, diffraction will not occur.
Step 7: Install the camera
Once the diffraction grating is on the webcam, the cable is passed through the housing using the rear groove and placed the web camera in the rear portion of the outer casing that is 30 degrees angle, and is aligned with the slits in the outer casing. Connect the webcam to your computer before securing the webcam into the bit, and open the camera application. The spectrometer is pointed to the light source and adjust the location of the network camera until the diffracted spectrum is located at the center of the image.
At this point, you can use double-sided tape to stick the webcam on the bottom surface.
Step 8: Test
To test if your spectrometer is working properly, point it to the light source and adjust the height of the light source and the spectrometer until both are aligned. You can use a bunch of books or other things to adjust the vertical alignment, I decided to use some old 3D printers consuetors.
Connect the webcam to your computer and open the camera application. The image should be composed of a neat diffractive spectrum.
You can use printouts to further decorate and mark spectrometers.
Step 9: Using analyzer software
Just have a picture of the spectrum may not provide too much information, so I have designed a program with Python to draw the intensity of the light. This will provide a relative distance between "peak", and can be further used to determine the wavelength present in the light source.
To run the program, you need to install Python on your computer and some additional open source libraries. You can use the following link https://www.python.org/ download Python.
Other libraries can be downloaded and installed through the terminal using PIP. Below, library and terminal commands are provided:
OpenCV - PIP Install OpenCV-Contrib-Python
Numpy - PIP installation Numpy
Matplotlib - PIP installation MATPLOTLIB
After installing all libraries, you can use the following Github storage Copline spectrum analyzer program: https://github.com/kousheeekc/diy-spectrometer-analyser
Run the program, you should see the webcam. Point the webcam to the light source, then press the "R" button on the keyboard to capture the import of interest. Click and drag the mouse on the spectrum, then press Enter. After selecting the area of interest, press the "S" button to capture the frame and use the graphical visualization analysis intensity. You can use the "Q" button to exit the program.
Step 10: Final results
After testing the spectrometer and software programs, you can start experimenting. You can align spectrometers, such as CFL bulbs, neon lights, incandescent bulbs, and even smart discoloration LED bulbs. You can also go outside to point the spectrometer to the clear part of the sky and explore the results.
To measure the wavelength of a light source, you can start from a light source (such as laser) with known wavelengths, and determine the relationship between peak position and wavelength.
You can also try other interesting experiments, such as detecting and measuring sodium in the salt and chlorophyll in olive oil. With this low-cost spectrometer, you can conduct a variety of simple and interesting experiments at home.
This project was originally an undergraduate physics student who could not perform practical experiments and laboratories due to new crown, although the process is very simple for anyone, there is no need to formally physical background. I really want to see your own version of the spectrometer, in addition to this, you can solve feedback, questions, comments, and doubts in the following reviews.
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