Old Blu-Ray Players Can Be Turned Into Microscopes (gizmodo.com) 20
YouTube's Doctor Volt repurposed a Blu-Ray drive, which are now easy to find on the cheap in the era of streaming content, to build a simple scanning laser microscope. Gizmodo reports: A couple of custom-designed and manufactured plastic parts were added to the mix to create a scanning bed for a sample that could move back in forth in one direction, while the laser itself shifted back and forth in the other. Unlike an optical microscope, where the entirely of an object is imaged at once, a scanning laser microscope takes light intensity measurements in increments, moving across an object in a grid and assembling a magnified image pixel by pixel. In this case, given the limitations of the Blu-Ray drive's spindle, which moves the sample being viewed back and forth, the image is assembled from 16,129 measurements (a 127x127 grid) and then scaled up to a 512x512 image.
A browser-based user interface written in Java allows focus adjustments and the scanning speed of the microscope to be modified, but at the slowest possible speed, the results are surprisingly good and recognizable. Certainly not comparable to what you'd get from lab equipment that costs tens of thousands of dollars, but for a re-purposed Blu-Ray drive you could get for less than $20 on eBay, this is an impressive hack.
A browser-based user interface written in Java allows focus adjustments and the scanning speed of the microscope to be modified, but at the slowest possible speed, the results are surprisingly good and recognizable. Certainly not comparable to what you'd get from lab equipment that costs tens of thousands of dollars, but for a re-purposed Blu-Ray drive you could get for less than $20 on eBay, this is an impressive hack.
Javascript not Java (Score:5, Informative)
Gizmodo should really know the that Java and Javascript are unrelated, he made a Javascript web app to run the scanner. He scans an area a bit less than 1mmx1mm at 126x126 points (i.e. over 3200 dpi) which is not that impressive, but he states the limitation is that he used a coarse spindle to move on.
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It's still neat. I like to see creative use of electronics waste.
Re:Javascript not Java (Score:5, Interesting)
I found it interesting and a great example of new ideas from obsolete tech. Do you know many early brushless motors for RC planes came from repurposing CD ROM motors about 15 years ago? https://hackaday.com/2009/11/1... [hackaday.com]
These articles are similar to the DIY laser printers from DVD drives [youtu.be] or sander/grinders from old HDD carcasses.
Some people enjoy reusing old equipment for new items: Cell phone and laptop cameras, laptop batteries, DIY power walls, homemade wind turbines, etc. Nerds come in all shapes and sizes.
Not that impressed (Score:2)
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You might actually be his dad. I would have taken that shameful secret to the grave to be honest.
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Big deal. It looks like nature beat your little project by 541 million years.
"The first eyes appeared about 541 million years ago – at the very beginning of the Cambrian period when complex multicellular life really took off "
https://www.newscientist.com/d... [newscientist.com]
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God has a Boltzmann brain, so it's less impressive especially when you consider it took him billions of years to figure it out.
A glancing blow (Score:2)
Haha!
Mac-GUY-ver... (Score:1)
A much easier and more powerful option (Score:4, Interesting)
A much easier way to build a more powerful and convenient laser microscope:
1) bend a small eyelet into the end of a paperclip, just big enough to suspend a single drop of water
2) shine laser through the droplet at a white wall
You'll be able to watch all the microbes in the water swimming around in real time, with size limited by the distance to the wall, and continuous "resolution" limited by the diffraction limit of the the wavelength of the light used. A BlueRay's blue-violet laser should be almost as good as it gets in the visible spectrum - I don't think there's a convenient source for deep violet lasers.
For size comparisons - a single blue-ray pit is 130x150nm, I would assume that's close to the detection limit of a scanning laser microscope using the same 405nm laser. Meanwhile bacteria are mostly in the .2-2um range (200-2,000nm), and while the diffraction ring distortions do obscure much of the detail, you can still easily make out the shapes of the much smaller organelles within them.
Of course that only works for magnifying transparent objects, not opaque surfaces. And it's not nearly as gratuitously geeky as building your own scanning microscope.
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I would say not much? I've only played with it a couple times, and that was using much larger-wavelength red lasers.
Optics are not my wheelhouse, but I'm pretty sure the "graininess" is directly related to the same interference principles that let it work as a microscope in the first place (non-laser light won't work). Though it might also be an artifact of imperfections in the laser itself - i.e. not emitting a perfectly uniform beam of laser light. Seems like for most applications beam uniformity doesn'
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The coherence length for a typical laser diode or gas laser is very short, so while the light is monochromatic, it is not coherent.
Lasers with a long coherence length, as would be suitable for holography or interferometry, have to be specially constructed and controlled. Common lasers are not.