This project was aided by earlier efforts hacking the Blu-ray laser from the XBox to turn it into a PCB printer. The original work is also really interesting http://www.diyouware.com/node/161
What a fantastic piece of work! I just built the open theremin project from the same group. I love the open hardware movement. As someone who does confocal microscopy all the time this is particularly awesome.
Only tangentially related, but are there any projects out there that modify CD or DVD readers to make it possible to read the raw (analog) pits and lands from the disc? When I was rescuing the last batch of burned CDs from my teen years a few years ago I unsurprisingly had some with lots of read errors. Googling around only lead me to forum threads where people recommended certain drives that would be very good at error recovery, but I thought it might be even better if you could get the raw stream from the disc and then do all the EFM reversal etc in software with more advanced analysis, brute forcing etc. But nothing of this kind seemed to exist.
'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.'
From waaaaay back, I remember CDRWin by Golden Hawk was the best piece of software out there to rip CD's, with their error recovery, options to re-read the same thing > 50x, alllowing the whole process to take hours but produce results. Not sure if you tried that one yet? Not what you are looking for, but probably the best off-the shelf solution that exists (though state of the art may have changed in the last decade)...
I was just thinking of doing the reverse: defeating game console DRM by artificially generating the analog signals normally picked up by the photodiode array.
Tangential question: does anyone have recommendation for a good beginner's microscope? Preferably that plays well with Linux and can be used to record photos/short videos etc. Something to get the kids excited :)
Take your chances with any of the inexpensive USB microscopes. I remember being thrilled as an adult to pick up one of the old Intel QX3 microscopes for photographing small parts. Anything you get in that vein will be much better today.
~50 EUR, random no-name USB microscopes are surprisingly good these days. I use them for inspecting PCBs and SMT solder jobs.
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.
I got one used from a university for around $50. I can mount my phone onto it (aftermarket attachment) to get pretty cool images. I don’t have any handy now, but here are some I took with my phone just in my hand.
Thanks! The photos are quite impressive - I was thinking of buying a new one but having seen these, I'll probably also look for a good quality used one.
Similar to cameras, going used and skipping fancy features can get you incredible glass for very low prices. My scope is a V 350 Wilomed which normally goes for around $400 CAD on the used market.
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.
A $10 USB microscope is a lot of fun for children.
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..
> 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
>The OpenFlexure Microscope is a customisable, open-source optical microscope, using either very cheap webcam optics or lab quality, RMS threaded microscope objectives.
Given the price of commercial confocal microscopes (even second hand), it could be very handy.
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
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 know about cylinder records, but for typical vinyl disc records, the biggest issue I've heard about with contactless transfer is that a needle will displace dust particles while (obviously) a laser will not.
“a needle will displace dust particles while (obviously) a laser will not.”
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.
The most advanced technology can be reduced in price by 5 orders of magnitude as long as its needed to amuse the general public. Look at the supercomputer in your hand or pocket.
Only 5? The raspberry pi 4 has nearly the same computational power as the servers I did my first research projects on and uses something like 1/100th of the wattage? I actually how no idea how much it cost but I imagine it was more than $5*50
well, a lot of the cost of medTech equipment lies in the certification and SLA.
there's a reason why a medical rated scissor is 1000 USD and the same sold on amazon is 20 USD.
This project was aided by earlier efforts hacking the Blu-ray laser from the XBox to turn it into a PCB printer. The original work is also really interesting http://www.diyouware.com/node/161
It seems almost meta that they have scanned the pips on a CD https://www.gaudi.ch/GaudiLabs/wp-content/uploads/LaserScanC...
What a fantastic piece of work! I just built the open theremin project from the same group. I love the open hardware movement. As someone who does confocal microscopy all the time this is particularly awesome.
Only tangentially related, but are there any projects out there that modify CD or DVD readers to make it possible to read the raw (analog) pits and lands from the disc? When I was rescuing the last batch of burned CDs from my teen years a few years ago I unsurprisingly had some with lots of read errors. Googling around only lead me to forum threads where people recommended certain drives that would be very good at error recovery, but I thought it might be even better if you could get the raw stream from the disc and then do all the EFM reversal etc in software with more advanced analysis, brute forcing etc. But nothing of this kind seemed to exist.
A major issue is that tracking (ie. Getting the laser to follow the route of the written data) is usually the thing that fails when reading disks.
Even if you had access to raw laser data, you can't fix the tracking after reading it...
side note, the magnetic adjustment coils on laser lenses are a thing of beauty..
On https://web.archive.org/web/20090318021921/http://club.cdfre... someone writes:
'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.'
From waaaaay back, I remember CDRWin by Golden Hawk was the best piece of software out there to rip CD's, with their error recovery, options to re-read the same thing > 50x, alllowing the whole process to take hours but produce results. Not sure if you tried that one yet? Not what you are looking for, but probably the best off-the shelf solution that exists (though state of the art may have changed in the last decade)...
I was just thinking of doing the reverse: defeating game console DRM by artificially generating the analog signals normally picked up by the photodiode array.
this is how https://shop.terraonion.com/en/home/17-Terraonion_MODE_Dream... works Its so trivial someone managed to implement it in a $3 ESP32, you can download firmware for free at https://www.fenrir-ode.fr/firmware/
forgot there is also playstation one using ESP32 https://github.com/x-station/xstation-releases
After having watched "Dissecting the CD Player: How to Turn Shiny Plastic into Music" by Technology Connections https://www.youtube.com/watch?v=3yJqlD9RxD4 and https://www.youtube.com/watch?v=7olNiMCz9to I went on a CDROM research binge. Found this on my way https://debugmo.de/2007/07/read-your-dvds-the-raw-way/ Its about DVDs (has data dump plus code), but you can use same mechanism to easily modify CDROM drive using $4 piece of hardware (ebay "EZ-USB fx2lp cy7c68013a board").
There is also LaserDisc preservation by capturing raw rf signal https://www.domesday86.com/?page_id=978
Hugged to death. Archive link: https://archive.is/bpvKq
Tangential question: does anyone have recommendation for a good beginner's microscope? Preferably that plays well with Linux and can be used to record photos/short videos etc. Something to get the kids excited :)
Take your chances with any of the inexpensive USB microscopes. I remember being thrilled as an adult to pick up one of the old Intel QX3 microscopes for photographing small parts. Anything you get in that vein will be much better today.
~50 EUR, random no-name USB microscopes are surprisingly good these days. I use them for inspecting PCBs and SMT solder jobs.
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.
I got one used from a university for around $50. I can mount my phone onto it (aftermarket attachment) to get pretty cool images. I don’t have any handy now, but here are some I took with my phone just in my hand.
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!
Thanks! The photos are quite impressive - I was thinking of buying a new one but having seen these, I'll probably also look for a good quality used one.
Similar to cameras, going used and skipping fancy features can get you incredible glass for very low prices. My scope is a V 350 Wilomed which normally goes for around $400 CAD on the used market.
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!
A $10 USB microscope is a lot of fun for children.
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..
From the same website: http://www.gaudi.ch/GaudiLabs/?page_id=328
> 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
>The OpenFlexure Microscope is a customisable, open-source optical microscope, using either very cheap webcam optics or lab quality, RMS threaded microscope objectives.
https://openflexure.org/projects/microscope/
Given the price of commercial confocal microscopes (even second hand), it could be very handy.
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
Let’s add micro fluidics and we can build a flow cytometer too!
I was expecting the pits of a CD to be of two clear sizes. But I see a lot of range.
Is error correction something that's in constant operation for all discs of all qualities and ages?
Very nice!
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 know about cylinder records, but for typical vinyl disc records, the biggest issue I've heard about with contactless transfer is that a needle will displace dust particles while (obviously) a laser will not.
“a needle will displace dust particles while (obviously) a laser will not.”
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.
I'm astonished that this is a DIY project... remarkable work!
The most advanced technology can be reduced in price by 5 orders of magnitude as long as its needed to amuse the general public. Look at the supercomputer in your hand or pocket.
Only 5? The raspberry pi 4 has nearly the same computational power as the servers I did my first research projects on and uses something like 1/100th of the wattage? I actually how no idea how much it cost but I imagine it was more than $5*50
5 orders of magnitude means the number of zeros. $50 -> $5,000,000
well, a lot of the cost of medTech equipment lies in the certification and SLA. there's a reason why a medical rated scissor is 1000 USD and the same sold on amazon is 20 USD.
That is an awesome job.
Confocal systems are six- to seven-digit bits of kit.
This is AMAZING, what a fantastic project!
It says the DVD bumps are 320-740 nm. Why does the demo image have only 1100 nm resolution?
The bumps are 740nm apart, but the laser is 1.1micrometer wide or 1100nm as shown in this diagram https://www.gaudi.ch/GaudiLabs/wp-content/uploads/Pits-1024x...
Great job, very impressive.
Well this is amazing. Wow.
That is super cool!