Join us on Wednesday, June 23 at noon Pacific for the Microscopy Hack Chat with Zachary Tong!
There was a time when electronics was very much a hobby that existed in the macroscopic world. Vacuum tubes, wire-wound resistors, and big capacitors were all mounted on terminal strips and mounted in a heavy chassis or enclosure, and interfacing with everything from components to tools was more an exercise in gross motor skills than fine. Even as we started to shrink components down to silicon chips, the packages we put them in were still large enough to handle and see easily. It’s only comparatively recently that everything has started to push the ludicrous end of the scale, with components and processes suitable only for microscopic manipulation, but that’s pretty much where we are now, and things are only likely to get smaller as time goes on.
The microscopic world is a fascinating one, and the tools and techniques to explore it are often complex. That doesn’t mean microscopy is out of the wheelhouse of the average hacker, though. Zachary Tong, proprietor of the delightfully eclectic Breaking Taps channel on YouTube, has been working in the microscopic realm a lot lately. We’ve featured his laser scanning confocal microscope recently, as well as his latest foray into atomic force microscopy. In the past he has also made DIY acrylic lenses, and he has even tried his hand at micromachining glass with lasers.
Zach is pretty comfortable working in and around the microscopic realm, and he’ll stop by the Hack Chat to share what he’s been up to down there. We’ll talk about all the cool stuff going on in Zach’s lab, and see what else he has in store for us.
Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, June 23 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
When one thinks about microscopy, it seems to be mostly qualitative. Looking at a slide teeming with bacteria or protozoans is less about making measurements and more about recognizing features and describing their appearance. Not all microscopes are created equal, though, with some being far more optimized for making fine measurements of the microscopic realm.
This 3D-printed confocal laser scanning microscope is a good example of an instrument for measuring really small stuff. As [Zachary Tong] points out, confocal scanning microscopy uses a clever optical setup to collect light from a single, well-defined point within a sample; rather than getting an image of all the points within a two-dimensional focal plane, the scanning function moves the focal point around through the sample in three dimensions, capturing spatial data to go along with the optical information.
The stage of [Zach]’s microscope is based on OpenFlexure’s Delta Stage, an open-source, 3D-printed delta-bot motion control platform that’s capable of positioning samples with sub-micron precision. Above the stage are the deceptively simple optics, with a laser diode light source, an objective lens, and a photodiode detector behind a pinhole. The detector feeds a homebrew trans-impedance amplifier that captures data at millions of points as the sample is moved through a small three-dimensional space. All that data gets crunched to find the Z-axis position corresponding to the maximum intensity at each point.
It takes a while to gather all this data — up to several days for even a small sample — but it works pretty well. [Zach] already has some ideas for reducing noise and speeding up the scan time; perhaps a stage based on DVD parts like this one would be faster than the delta stage. We look forward to seeing his improvements.
Continue reading “3D-Printed Laser Scanning Confocal Microscope Measures Microns”
Confocal microscopy is an imaging technique that provides higher resolution micrographs than that of traditional optical microscopy. Confocal microscopes attain this higher resolution from an image sensor behind a pinhole. By eliminating out of focus light, and by scanning the specimen back and forth under the microscope, a very high resolution image may be produced. This technique has applications ranging from life sciences to semiconductor work. For this year’s Hackaday Prize, [andreas.betz] is building a confocal microscope using little more than a Blu-ray drive read head.
[andreas]’ build uses a standard Playstation 3 Blu-ray drive mechanism. The read head for this mechanism is well documented, but [andreas] still has to drive the laser and the voice coils for this machine to do anything. With the Blu-ray drive working, only the optics remained.
Just this last week, [andreas] imaged the die of a transistor with a resolution of about 680nm. An inductor was also imaged, showing a track separation of about 10um. This is approaching the limits of optical microscopy, and the apparatus is simple enough for anyone to replicate.
As a feat of technical ingenuity, this is a great project. It’s one of the best we’ve seen for the Citizen Science portion of the Hackaday Prize, and can’t wait to see what other images [andreas] can make with this machine.