DVD Laser Scanner Microscope
gaudi.ch
gaudi.ch
'I used an oscilloscope to find a sweet spot in the analog signal path of an audio CD player (an old Sanyo - the older the better, for this kind of stuff...) where a pre-filtered and amplified version of the laser readout is available - in this particular player, this is basically a test header marked "EFM" (which provides a good hint to its function - it's the last analog stage of the signal, just prior to entering the digital Fourteen-to-Eight demodulator).
This point is probed and fed into a high-speed AD converter (12 bit res, 50 Msamples/sec) that is hooked to an FPGA. I implemented a flank detector and a run-length encoder in VHDL.'
And later in the thread:
'Old audio CD players are so amazingly stupid, they will happily "play" CD-ROM discs if you feed it with one. This is truly ideal for analysis purposes.'
There is also LaserDisc preservation by capturing raw rf signal https://www.domesday86.com/?page_id=978
Even if you had access to raw laser data, you can't fix the tracking after reading it...
https://imgshare.io/image/ppVR4g https://imgshare.io/image/ppVlc7 https://imgshare.io/image/ppVaiq
My kids really enjoy it, so that’s good enough for me. I’d definitely take a look around for cheap used stuff!
I’d happily pay closer to that amount for this scope. When I got it I thought I’d be getting something much worse given the price, but it’s a real lab-capable device.
If you got something considerably less powerful I bet you could spend very little and still have a ton of fun. You definitely don’t need something this powerful.
I hope you find something awesome!
Model names seem to change daily, but they are all very similar. Standard USB video device-class, so no software necessary. I just use guvcview under Linux.
Pick one that has "full HD" in the name - it's usually not true 1080p, but in my experience the picture quality is still better than the other ones that will have a PAL-like sensor in it.
Also, get one with a stand where you can adjust the height of the scope above the object with a screw.
> To use a regular usb computer web-cam as a microscope, only a few modifications are needed. Basically flipping the lens upside down does the trick. No extra optics needed
Try pointing at at your fingerprint, then try to control a sweat gland (which sits between the ridges) with thought alone. With practice you can do it!
The first time you see a sweat gland erupt with sweat you'll be disgusted..
I wonder if it would be possible to use different wavelengths (DVD and blueray lasers) to superpose images: even if the resolutions are different, it would allow using 2 reagents at once
Is error correction something that's in constant operation for all discs of all qualities and ages?
I was going to do something like this for contactless transfer (ideally live) for a box of old cylinder records that I have. I still have the DVD head and fiber optics, for the confocal setup. Cylinder records are nice because they only have one channel of audio, with the waveform represented as a vertical displacement, perfect for something like this, on a screw drive, that just has to read depth and correct some slight tracking error.
I don’t think this setup will displace dust particles, but that’s not completely obvious. https://en.wikipedia.org/wiki/Optical_tweezers: “The trapped particles are usually micron-sized, or smaller.”
I think the smallest dust particles are small enough to be manipulated in an optical tweezer.
Confocal systems are six- to seven-digit bits of kit.