Highly Configurable Open Source Microscope Cooked Up In FreeCAD

September 9, 2021 by Dave Rowntree 22 Comments

What do you get when you cross a day job as a Medical Histopathologist with an interest in 3D printing and programming? You get a fully-baked Open Source microscope, specifically the Portable Upgradeable Modular Affordable (or PUMA), that’s what. And this is no toy microscope. By combining a sprinkle of off-the-shelf electronics available from pretty much anywhere, a pound or two of filament, and a dash of high quality optical parts, PUMA cooks up quite possibly one of the best open source microscopy experiences we’ve ever tasted.

GitHub user [TadPath] works as a medical pathologist and clearly knows a thing or two about what makes a great instrument, so it is a genuine joy for us to see this tasty project laid out in such a complete fashion. Many a time we’ve looked into an high-profile project, only to find a pile of STL files and some hard to source special parts. But not here. This is deliberately designed to be buildable by practically anyone with access to a 3D printer and an eBay account.

The project is not currently certified for medical diagnostics use, but that is likely only a matter of money and time. The value for education and research (especially in developing nations) cannot really be overstated.

A small selection of the fixed and active aperture choices

The modularity allows a wide range of configurations from simple ambient light illumination, with a single objective, great for using out in the field without electricity, right up to a trinocular setup with TFT-based spatial light modulator enabling advanced methods such as Schlieren phase contrast (which allows visualisation of fluid flow inside a live cell, for example) and a heads-up display for making measurements from the sample. Add into the mix that PUMA is specifically designed to be quickly and easily broken down in the field, that helps busy researchers on the go, out in the sticks.

The GitHub repo has all the details you could need to build your own configuration and appropriate add-ons, everything from CAD files (FreeCAD source, so you can remix it to your heart’s content) and a detailed Bill-of-Materials for sourcing parts.

We covered fluorescence microscopy before, as well as many many other microscope related stories over the years, because quite simply, microscopes are a very important topic. Heck, this humble scribe has a binocular and a trinocular microscope on the bench next to him, and doesn’t even consider that unusual. If you’re hungry for an easily hackable, extendable and cost-effective scope, then this may be just the dish you were looking for.

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An assortment of whole-mouth toothbrushes that brush all of your teeth at once, in the span of 30 seconds.

Don’t Bristle; Teethbrush Won’t Hurt You

September 7, 2021 by Kristina Panos 33 Comments

Good dental hygiene is the first line of defense when it comes to your health, and– you’re already bored, aren’t you? It’s totally true, though. Take care of your teeth, and the rest of you has a better chance of staying fairly healthy.

This is like, the one thing we have control over after diet and exercise, and most people just plain fail on this front. They brush for 30 seconds, tops. Or they rarely floss. Maybe they’ve never even considered brushing or scraping their tongue.

Okay, fine. You don’t want to spend the recommended two minutes twice a day working the brush around your mouth. The good news is, technology has finally caught up with you and your habits, if you can call them that. How about using something that can truly be called a teethbrush? As in, it brushes all of your teeth at once? Well, half of your teeth anyway. Allegedly, you can spend as little as 10 seconds on each arch and effectively scour your smile — that’s because the thing vibrates at an astonishing 40,000 per minute or so.

Sounds kind of scary, doesn’t it? Wait ’til you hear how much they cost. One brand is $150 off the bat, and replacement heads are close to $40 each, although they’re supposed to last for six months each (eww!). Most of them have some fancy extras that make the cost more palatable, such as a tooth-whitening mode.

What do you think? Would you use a teethbrush? We’re still on the fence. It could be interesting to develop our own, but you have to crawl before you can run. Guess we’ll start with a manual.

Squares of sample materials placed on the laser bed awaiting the sensing head

Smart Laser Cutter Ad-on Detects Material Optically

September 6, 2021 by Dave Rowntree 9 Comments

Come on now, admit it. You’ve done it. We’ve done it. You know — you were really sure that sheet of plastic stock you found lying around the hackerspace was acrylic right? You dialled in the settings, loaded the design, set the focus and pushed the little green ‘start’ button. Lots of black smoke, fire, and general badness ensued as you lunged for the red ‘stop’ button, before lifting the lid to work out how you’re going to clean this one up.

That was not acrylic. That was polycarbonate.

What you need is the latest gadget from MIT: SensiCut: A smart laser cutter system that detects different materials automatically.

The technique makes use of so-called ‘speckle imaging’ where a material illuminated by a laser will produce a unique pattern of reflected spots, or speckles into a camera. By training a deep neural model with a large set of samples, it was found possible to detect up to 30 types of material with 98% accuracy.

The pre-baked model runs on a Raspberry PI zero with an off-the-shelf camera all powered from a power bank. This allows the whole assembly to simply drop onto an existing laser cutter head, with no wiring needed.

Even if you’re a seasoned laser cutter user, with a well-controlled stock pile, the peace-of-mind this could give would definitely be worth the effort. A more detailed description and more videos may be found by reading the full paper. Here’s hoping they release the system as open source, one day in the not-to-distant future. If not, then, you know what to do :)

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How To Get Good With Wood

September 6, 2021 by Tom Nardi 6 Comments

It’s perhaps unsurprising that we don’t see much in the way of woodworking here at Hackaday; after all, this is a plastics and metal community if there ever was one. But that doesn’t mean you’ll never come across a situation where a dead tree needs to be cut or shaped to your will, so we appreciate [Eric Strebel] demonstrating some tips and best practices for working with this exceptionally versatile building material.

The first video assumes you’re a lumber neophyte, and goes over topics such as the different species of wood you’re likely to find at the hobby shop, proper sanding technique, and the differences between cutting with and against the grain. Some of the different cutting tools you can use are also covered, ranging from the humble hobby knife to the band saw. As always, [Eric] sprinkles the video with tips and tricks gained from his considerable professional experience, such as using some glue and a bit of sawdust to fill in any gaps left behind by an uneven joint.

In the second video, things start getting more advanced. [Eric] demonstrates how you can create custom laminates, and how wood can be permanently bent into arbitrary shapes with sufficient steam and clamping pressure. By combining these new techniques with the basic concepts covered in the first video, surprisingly complex shapes can be formed with minimal effort.

[Eric] previously put together a similar series of videos on working with acrylic, a material that’s arguably far more familiar to the Hackaday readership. But whatever material you use, the takeaway message from this series is clear: get the right tools, learn the techniques, and professional results are well within your reach.

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See The Unseen With This Magnetic Field Visualizer

September 1, 2021 by Tom Nardi 8 Comments

The average Hackaday reader likely knows, at least in the academic sense, what a magnetic field looks like. But as the gelatinous orbs in our skull can perceive only a tiny fraction of the EM spectrum, we have to take those textbook diagrams at face value. That is, unless you’ve got one of these nifty magnetic field visualizers developed by [Dr.Stone].

Using an XMC1100 microcontroller development board and a TLV49 3D magnetic sensor, the device is able to track the poles of a magnet in real-time and produce an approximation of what the field lines would look like on its electronic paper display. Relative field strength is indicated by the size of the visualization, which allows the user to easily compare multiple magnets. Incidentally, [Dr.Stone] notes that the current version of the hardware and software can only handle one magnet at a time; visualizing complex magnetic fields and more than two poles would take an array of sensors and likely a more powerful processor.

Do you need to visualize the field lines around a magnet? Perhaps not. But being able to quickly get an idea of how strong a magnet is and identify where its poles are could certainly come in handy. We’d like to see [Dr.Stone] take the project to the next phase and turn this into a handheld device for convenient workbench use. It would be a lot less messy than some of the previous methods we’ve seen for visualizing magnetic fields, though if you’re only worried about field strength, there’s arguably more straightforward ways to display it.

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Better 3D Scans Through A Slowed Down Turntable

August 31, 2021 by Tom Nardi 6 Comments

3D scanners aren’t cheap, and the last thing you want to see after purchasing one is bad data. But that’s what [Dave Does] and others were getting from their Revopoint POP scanners until some communal brainstorming uncovered the reason: the motorized turntable that came with the Kickstarter edition of the product was spinning too fast for the software to accurately keep track of the object. So he decided to replace the stepper motor controller in his turntable and document the process for anyone else who’s scanner might be struggling.

In the video below, [Dave] pops open the plastic case of the turntable and reveals a pretty sparse interior. There’s an incredible amount of empty space inside, and even some mounting studs to screw down new components, should you want to get into some hardcore upgrades. But for his purposes, a generic stepper motor controller that featured a potentiometer to adjust the speed was enough. He found a suitable board online for around $5 USD, and got to designing a 3D printed bracket that mates up to the existing screw holes on the turntable.

But it’s not exactly a drop-in replacement. For one thing, you’ve got to pop a hole in the side of the enclosure for the potentiometer knob to stick out of. You’ve also got to solder wires coming from the original DC jack and power switch to the new board to get it hooked up, but at least the motor plugs right in. In the video below, you can see [Dave] demonstrate the impressively deep throttle capability of the new driver.

If you’d rather build than buy, we’ve covered some impressive DIY turntables in the past that could fit the bill nicely, from automatic models that handle camera control to fully 3D printed versions that you’ve got to crank yourself.

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Impromptu Metal Detector Built From The Junk Bin

August 30, 2021 by Tom Nardi 12 Comments

Have you ever found yourself suddenly in need of finding a small metal object hidden in the woods? No? Well, neither have we. But we can’t say the same thing for [zaphod], who’s family was hoping to settle a dispute by finding the surveyor stakes that marked the corners of their property. It was a perfect job for a metal detector, but since they didn’t own one, a serviceable unit had to be assembled from literal garbage.

To start with, [zaphod] had to research how a metal detector actually works. After reviewing the pros and cons of various approaches, the decision was made to go with a beat frequency oscillator (BFO) circuit. It’s not the greatest design, it might even be the worst, but it could be built with the parts on hand and sometimes that’s all that matters. After packing a 2N3904 transistor, an LM386 amplifier, and every Hackaday reader’s favorite chip the 555 timer into an enclosure along with some of their closest friends, it was time to build the rest of the metal detector.

The sensor coil was made by salvaging the wire from an old fluorescent lamp ballast and winding it around the lid of a bucket 27 times. This was mounted to the end of a broom handle with some angle pieces made from PVC sheet material, being careful not to use any metal fasteners that would throw off the detector. With the handle of an old drill in the middle to hold onto, the metal detector was complete and actually looked the part.

So did [zaphod] save the day by finding the surveyor stakes and reconnoitering the family’s plot? Unfortunately, no. It wasn’t a technical failure though; the metal detector did appear to work, although it took a pretty sizable object to set it off. The real problem was that, after looking more closely into it, the surveyors only put down one stake unless they are specifically instructed otherwise. Since they already knew where that one was…

If your homemade metal detector can’t find something that was never there, did it really fail? Just a little something to meditate on. In any event, when even the cheapest smart bulb is packing a microcontroller powerful enough to emulate early home computers, we’re always happy to see somebody keep the old ways alive with a handful of ICs.