#spectroscope

Gabor Hejagheja
2025-01-12

The web based analyzer for the spectrometer is coming together, although I still have to figure out a few things. This screencapture shows a few of the features, but nothing serious, just sliding the sliders and buttoning the buttons, then cycling through a few colors on the lamp in front of the phone.

It's still WIP but you can try it here: gheja.github.io/spectro-web/sr

Gabor Hejagheja
2025-01-08

I started to work on a mini pocket spectrograph, the 3D model will be available for download, I just need to tune a few things.

I am also working on a little web based stuff to make sense of the things seen, strictly locally in the browser, on the client side.

It's a fun random side project, though I already bought about 8 different light bulbs just to see their spectrum...

The spectrograph, 3D printed, before painting.The spectrograph painted black, assembled.A photo of the spectrum of an RGB LED lamp set to about warm white light, seen through my spectrograph.
2023-09-23

In 1814, Joseph von Fraunhofer discovered that each element produces different spectral lines. #Poetry #Science #History #Chemistry #Physics #Spectroscope #Fraunhofer (sharpgiving.com/thebookofscien)

Drawing of an early spectrometer, three optical tubes mounted around three sides of a prism.
2023-08-26
A Spectral Ocular. The making of an instrument to colour the world anew.

#spectroscope #spectral #ocular #colour #monocular

https://anarchive.fo.am/wabisabi/spectroscope/
Purple and concentric circles narrowing towards the centre, and changing from red to green and blue. Blurry trees in the top left corner, seen through a translucent multicoloured monocular.
2021-08-09

Using a Laser to Blast Away a Bayer Array

A Bayer array, or Bayer filter, is what lets a digital camera take color photos. It's an array of tiny color filters that sit on top of a camera's CCD. The filter makes it so that each sub-pixel in the image sensor only sees red, green, or blue light. The Bayer filter is an elegant tool that gives us color digital photos, but what would you do if you wanted to remove one?

[Les Wright] has devised a way to remove the Bayer filter from the Raspberry Pi Camera. Along with filtering red, green, and blue light for their respective sensors, Bayer filters also greatly reduce the amount of UV and IR light that make it to the CCD sensor. [Les] uses the Raspberry Pi camera in his Pi-based Spectrometer, and he wants to remove the Bayer filter to improve and expand its sensitivity.

Of course, [Les] isn't the first one to want to do this. Some have succeeded in physically scratching the filter off of the CCD, but because the Pi Camera has vital circuitry around the outside of the sensor, scratching the filter off would likely destroy the circuitry. Others have stripped it off using chemical means, so [Les] gave this a go and destroyed no small number of cameras in his attempt to strip the filter off with solvents like DMSO, brake fluid, and industrial paint stripper.

A look at the CCD, halfway through the process.

Inspired by techniques used in industry, [Les] eventually tried to use a several-kW nitrogen laser to burn off the filter (which seems appropriate given his experience with lasers). He built a rig that raster scans the laser across the sensor using stepper motors to drive micrometer bases. A USB microscope was included to allow progress to be monitored, and you can see a change in the sensor's appearance as the filter is removed.

After blasting off the Bayer filter, [Les] plugged his improved camera into his home-built spectrometer and pointed it outside. The new camera gives the spectrometer much more uniform sensitivity and allows [Les] to see further into the IR and UV bands. The spectrometer can even detect the Fraunhofer lines—subtle dips in the sun's spectrum from absorption by molecules in the atmosphere.

This is incredible for a DIY setup and instrument, and we can't wait to see what [Les] does next to improve his measurements. If your spectrometry needs are more mass than visual, take a look at this home-built mass spectrometer. Home spectrometers aren't just for examining light spectra—they can also be used to judge the ripeness of fruit!

#laserhacks #lasers #optics #picam #raspberrypi #raspberrypicamera #spectrometer #spectroscope

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2021-04-23

Pi-Based Spectrometer Puts the Complexity in the Software

Play around with optics long enough and sooner or later you're probably going to want a spectrometer. Optical instruments are famously expensive, though, at least for high-quality units. But a useful spectrometer, like this DIY Raspberry Pi-based instrument, doesn't necessarily have to break the bank.

This one comes to us by way of [Les Wright], whose homebrew laser builds we've been admiring for a while now. [Les] managed to keep the costs to a minimum here by keeping the optics super simple. The front end of the instrument is just a handheld diffraction-grating spectroscope, of the kind used in physics classrooms to demonstrate the spectral characteristics of different light sources. Turning it from a spectroscope to a spectrometer required a Raspberry Pi and a camera; mounted to a lens and positioned to see the spectrum created by the diffraction grating, the camera sends data to the Pi, where a Python program does the business of converting the spectrum to data. [Les]'s software is simple by complete, giving a graphical representation of the spectral data it sees. The video below shows the build process and what's involved in calibrating the spectrometer, plus some of the more interesting spectra one can easily explore.

We appreciate the simplicity and the utility of this design, as well as its adaptability. Rather than using machined aluminum, the spectroscope holder and Pi cam bracket could easily be 3D-printer, and we could also see how the software could be adapted to use a PC and webcam.

#mischacks #diffraction #laser #optics #picam #python #raspberrypi #spectrometer #spectroscope #spectrum

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