Reading Data From A CD, With A Microscope

January 22, 2023 by Jenny List 18 Comments

There was a time when electronic engineering students studied the audio CD, for all its real-world examples of error correction and control systems. There’s something to be found in the system still for young and old though, and thus we were intrigued when we saw [Peter Monta] reading the data from a CD using a microscope.

CDs encode data as so-called pits and lands in a spiral track across a metalised surface, with a transition from pit to land signifying a logic 1 and a missing transition signifying a 0. Reading a section of the raw data is achieved in the first part of his write-up, but in the next installment he goes further into retrieving more data through stitching together microscope pictures and writing some code to retrieve data frames. He’s not quite at the audio playback stage, but he’s planning in the future to spiral-track a full image to rip an entire disc.

There are plenty of CD drives around to read audio the conventional way, but the techniques here still find a use where less ubiquitous media has to be read. In the last decade for example there was an effort to read the BBC Domesday Project from the 1980s, as it became clear that few of the original readers survived in working order.

Laser Scanning Microscope Built With Blu-ray Parts

December 23, 2022 by Lewin Day 14 Comments

Laser scanning microscopes are useful for all kinds of tiny investigations. As it turns out, you can build one using parts salvaged from a Blu-ray player, as demonstrated by [Doctor Volt].

The trick is repurposing the optical pickup unit that is typically used to read optical discs. In particular, the build relies on the photodiodes that are usually used to compute focus error when tracking a disc. To turn this into a laser scanning microscope, the optical pickup is fitted to a 3D printed assembly that can slew it linearly for imaging purposes.

Meanwhile, the Blu-ray player’s hardware is repurposed to create a sample tray that slews on the orthogonal axis for full X-Y control. An ESP32 is then charged with running motion control and the laser. It also captures signals from the photodiodes and sends them to a computer for collation and display.

[Doctor Volt] demonstrates the microscope by imaging a small fabric fragment. The scanned area covers less than 1 mm x 1 mm, with a resolution of 127 x 127, though this could be improved with finer pitch on the slew mechanisms.

While it’s hardly what we’d call a beginner’s project, this technique still looks a lot more approachable than building your own scanning electron microscope.

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DVD Drives Turned Into Microscopes

October 1, 2022 by Bryan Cockfield 24 Comments

With the advent of streaming services, plenty of people are opting to forego the collection of physical media. In turn, there are now a lot of optical drives sitting unused in parts bins and old computers. If you’d like something useful to do with this now-obsolete technology, you can have a try at turning one into a laser microscope.

This build requires two DVD pickups. By scanning once horizontally and once vertically and measuring the returning light from the DVD laser, an image can be created. For this build, the second pickup is used to move the object itself. The entire device is controlled by an Analog Discovery 2, although this principle could be ported to other microcontroller platforms. Thanks to the extremely fine laser in a DVD and the precise movements of the motors found in the control machinery, the images obtained using this method have the potential to be more detailed than comparable visible light microscopes.

While this isn’t quite scanning electron microscope territory, it’s good enough to clearly image the internal workings of a de-capped integrated circuit. Something like this could be indispensable for reverse-engineering ICs or troubleshooting other comparably small electronics, with resolutions higher than can typically be obtained with visible light microscopes. We’ve even seen similar builds in the past which build microscopes like this as dedicated lab equipment.

Hackaday Podcast 177: Microscopes, Telescopes, Telephonoscopes, And A Keyboardoscope?

July 15, 2022 by Kristina Panos 1 Comment

This week, Editor-in-Chief Elliot Williams and Assignments Editor Kristina Panos stood around talking like they weren’t thousands of miles apart. And we mean that literally: Kristina just got an up/down desk, and it turns out that Elliot’s had the exact same one for years.

In between the hammerings on Kristina’s house (she’s getting new siding), we kick things off by drooling over the first images from the James Webb Space Telescope, and compare a few of them to the same shots from Hubble.

We managed to save a bit of saliva for all the seriously swell keyboards and not-keyboards we saw throughout the Odd Inputs and Peculiar Peripherals contest, all of which are winners in our book.

This week, we ask the tough questions, like why would someone who has never played guitar want to build one from scratch? We can only guess that the answer is simply, ‘because l can’. As lazy as that reasoning may sound, this build is anything but.

Later on, we’ll ogle an ocean of PS/2 keyboards and their new owner’s portable testing rig, complain about ASMR, and laugh about a giant nose that sneezes out sanitizer.

Direct download. And burn it to CD-RW!

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Continue reading “Hackaday Podcast 177: Microscopes, Telescopes, Telephonoscopes, And A Keyboardoscope?” →

Trying Out A 3D Printed Microscope Lens Adapter

July 7, 2022 by Al Williams 11 Comments

If you want to take pictures of tiny things close up, you need a macro lens. Or a microscope. [Nicholas Sherlock] thought “Why not both?” He designed a 3D-printed microscope lens adapter that you can find on Thingiverse. Recently, [Micael Widell] tried it out with a microscope lens and you can see the results in the video below.

A $20 microscope lens allows for some amazing shots. There are two designs that fit different cropped-image and full-frame cameras. As you might expect, the depth of field is razor-thin, probably sub-millimeter. Additionally, with a 4X lens on a 35 mm sensor, the field of view is about 9 mm so you have to have a steady hand just to keep everything in frame.

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Blu-ray Microscope Uses Blood Cells As Lenses

April 22, 2022 by Anne Ogborn 12 Comments

When you think of high-throughput ptychographic cytometry (wait, you do think about high throughput ptychographic cytometry, right?) does it bring to mind something you can hack together from an old Blu-ray player, an Arduino, and, er, some blood? Apparently so for [Shaowei Jiang] and some of his buddies in this ACS Sensors Article.

For those of you who haven’t had a paper accepted by the American Chemical Society, we should probably clarify things a bit. Ptychography is a computational method of microscopic imaging, and cytometry has to do with measuring the characteristics of cells. Obviously.

This is definitely what science looks like.

Anyway, if you shoot a laser through a sample, it diffracts. If you then move the sample slightly, the diffraction pattern shifts. If you capture the diffraction pattern in each position with a CCD sensor, you can reconstruct the shape of the sample using breathtaking amounts of math.

One hitch – the CCD sensor needs a bunch of tiny lenses, and by tiny we mean six to eight microns. Red blood cells are just that size, and they’re lens shaped. So the researcher puts a drop of their own blood on the surface of the CCD and covers it with a bit of polyvinyl film, leaving a bit of CCD bloodless for reference. There’s an absolutely wild video of it in action here.

Don’t have a Blu-ray player handy? We’ve recently covered a promising attempt at building a homebrew scanning electron microscope which might be more your speed. It doesn’t even require any bodily fluids.

[Thanks jhart99]

Home Made Scanning Electron Microscope Shows Some Potential

March 21, 2022 by Dave Rowntree 7 Comments

Scanning electron microscopes are one of those niche instruments that most of us don’t really need all the time, but would still love to have access to once in a while. Although we’ve covered a few attempts at home-builds before, many have faltered, except this project over on Hackday.IO by user Vini’s Lab, which appears to be still under active development. The principle of the SEM is pretty simple; a specially prepared sample is bombarded with a focussed beam of electrons, that is steered in a raster pattern. A signal is acquired, using one of a number of techniques, such as secondary electrons (SE) back-scattered electrons (BSE) or simply the transmitted current into the sample. This signal can then be used to form an image of the sample or gather other properties.

The project is clearly in the early stages, as the author says, it’s a very costly thing to build, but already some of the machined parts are ready for assembly. Work has started on the drive electronics for the condenser stigmator. This part of the instrument takes the central part of the rapidly diverging raw electron beam that makes it through the anode, and with a couple of sets of octopole coil sets, and an aperture or two, selects only the central portion of the beam, as well as correcting for any astigmatism in the beam. By adjusting the relative currents through each of the coils, a quadrupole magnetic field is created, which counteracts the beam asymmetry.

Scanning control and signal acquisition are handled by a single dedicated card, which utilises the PIO function of a Raspberry Pi Pico module. The Pico can drive the scanning operation, and with an external FTDI USB3.0 device, send four synchronised channels of acquired sample data back to the host computer. Using PCIe connectors and mating edge connectors on the cards, gives a robust and cost effective physical connection. As can be seen from the project page, a lot of mechanical design is complete, and machining has started, so this is a project to keep an eye on in the coming months, and possibly years!

We have seen a few SEM hacks, here’s a teensy powered SEM hack from [Ben Krasnow] and here’s another attempt. For such a conceptually simple device, with such immense usefulness, its does seem a bit remiss that there aren’t more such projects out there.