Building A DIY Centrifuge For Blood Processing

September 17, 2026 by Zoe Skyforest 17 Comments

If you want to do certain types of lab work with blood, you’ll need a centrifuge. It’s often possible to find serviceable units on the used market, but they may not meet your requirements if you’re doing something quite specific. For that reason, [Thomas Nguyen] decided to build his own centrifuge from scratch.

His goal was to separate T cells from blood for further lab analysis, and he needed to be able to work with blood in 15 mL conical tubes. Capable centrifuges weren’t affordable, but he figured he could build his own quite easily. To that end, he enlisted a Raspberry Pi Pico, a 3D printer, and an A2212 brushless motor with a 30 amp electronic speed controller.

Soon enough, he had a design for a fixed-angle centrifuge design that could spin up blood products to the required speed for separation. It has useful safety features, like an MPU-6050 for vibration detection to shut down in case of dangerous imbalance, and an IR sensor for monitoring and controlling rotational speed. For now, the project is still in development, with the first version built and spinning. [Thomas] aims to check that the build operates safely and can separate fluids like dyed water and glycerol successfully before running it with real blood products.

We’ve seen other successful DIY centrifuge builds before, too. Sometimes, the lab hardware you need is the lab hardware you build yourself. If it works and does the job safely, it can be all that you need to get your science goals coming to fruition.

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Recreating Unobtainable Diagnostic Tools For The Jaguar XJ220

September 16, 2026 by Zoe Skyforest 22 Comments

If you own a Jaguar XJ220 or the rarer XJR-15, you’re probably not short on money or real estate. You may, however, be finding it hard to lay your hands on a diagnostic tool that is compatible with the ancient Zytek ECU. Thankfully, [Tom Radom], is working to change that.

As the owner of XJ220 chassis #50, [Tom] was unlucky enough to see the dreaded check engine light come on last year. He was lucky enough to get his hands on an SPD-1039 interface, built to talk to the Zytek ECU that runs the car. However, he was painfully aware that these devices are now incredibly rare and hard to come by, even given the tiny limited market of owners of 1990s Jaguar supercars. Thus, he set about building a replacement.

An initial effort to open up and reverse engineer the Zytek interface failed, mostly because it had been potted rather successfully in silicone. Thus, [Tom] took a new tack. He hooked up a logic analyser between the interface and the car, recording the traffic between the two. This captured data allowed [Tom] to recreate the interface using a FT232RNL bridge to chat to the Zytek engine control unit. There was no attempt to rebuild the software—the original DOS-based diagnostic still runs perfectly fine in an emulator. It was just the hardware interface from a serial port to the car that needed to be recreated.

[Tom] has been building the modules and supplying them to owners of XJ220, XJ220S, and XJR-15 models at no charge. He believes simply having a viable diagnostic tool available will increase the value of these classic cars by more than the costs he incurred to develop the interface. Interested parties can submit their details via webform on Port220.com.

For a modern vehicle, the ECU is everything. Without it, the car doesn’t run. That’s why we’ve seen some heroic fixes to rescue cars and get them back on the road. If you’re doing your own wizardry to talk to cars of the past, don’t hesitate to notify the tipsline.

Tips To Model Your Next CNC Cabinet In CAD Before Buying Anything

September 15, 2026 by Donald Papp 10 Comments

[Clough42] has started a new CNC control cabinet build, and uses it as an opportunity to demonstrate why he models the whole thing out in CAD before ordering parts or physically building anything. One may wonder why to bother, and the simple answer is to ensure there are no surprises or waste. [Clough42] has built plenty of these cabinets and there’s always something that isn’t as expected.

Modeling out an entire cabinet sounds like it should be easy, because today one can obtain 3D models for components from industrial suppliers with ease. In practice, it’s a process fraught with little gotchas.

For example, a STEP file of a component can lack convenient geometric snap points. An enclosure will be a single entity, without a separate door (and certainly not articulated at the hinge). [Clough42] shows ways to deal with all of these, and more, in Fusion 360. With a few simple techniques laying out an entire cabinet in CAD can be easy.

Planning before buying or building is a form of prototyping, and prototyping helps surface problems so they can be avoided before they become costly. This concept extents to design work as well; model everything out to avoid simple goofs like a screwdriver handle trapped by its surrounding bits.

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Making An Air-Powered Circular Saw With LEGO

September 12, 2026 by Maya Posch 9 Comments

The all-LEGO version barely cuts paper. (Credit: Jamie's Brick Jams, YouTube) — The all-LEGO version barely cuts paper. (Credit: Jamie’s Brick Jams, YouTube)

Although building a table saw out of LEGO is probably not the first thing that comes to mind when you look at those colorful bits of plastic, [Jamie] has been on a bit of a search for more applications of his LEGO-based air-powered motors. Naturally this led to the idea of doing something useful with it, like making a table saw you can actually use for real wood.

Starting off with a basic prototype using only regular LEGO pieces to get the mechanism figured out, [Jamie] then builds this up into said air-powered table saw featuring an actual metal blade. Suffice it to say that this isn’t something that you want your children to do with their LEGO while unsupervised.

The star of the show is of course the air-powered turbine that spins the blade. This is something that [Jamie] has been working on for a while, going through a number of prototypes to figure out a 3D printed geometry for the turbine blade that helps to convert as much of the high-pressure air into rotation.

Along the way it was also discovered that 3D printing saw blades is pretty hard, probably due to the lack of a sharp edge. This is definitely an area where it’s hard to beat a real table saw blade, with the added caveat that anything that’s good at cutting up boards of wood and sausages will just as happy slice through careless primate fingers.

In terms of safety features, the air supply is cut automatically with a sort of dead-man switch that requires you to keep one hand on it while using the final table saw design. There also an auto-feeding system added that tries to guide the board into the saw, but this turned out to be finicky. Suffice it to say that an air compressor and a handful of non-LEGO-approved components created a pretty convincing table saw.

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How To Fold Curved Lines In Metal Without Fancy Tools

September 11, 2026 by Donald Papp 19 Comments

Folding a sheet of metal in a straight line is one thing, but how does one fold multiple curved lines into a sheet of aluminum without fancy machines? [John] demonstrates how to do exactly that with little more than hand tools and a fair bit of patience. The secret is drilling a lot of small holes along each fold line.

First, a bit of background. [John] wanted to fabricate a curved piece of aluminum as cover that would match the sleek aerodynamic lines of a Belly Tank Lakester. The trick is that there isn’t a single straight line to be found, and the fold lines are all curves. How can one do such folding with only hand tools?

[John] found that fabrication was possible by drilling small holes all along each fold line, then carefully bending as needed. The line of holes weakens the metal, acting like a score line, and allow the required curves to be made cleanly. There’s some finishing work and straightening involved, but the hard part of making the actual folds is taken care of.

One method that didn’t work was cutting a shallow groove in the metal to create something like a pre-scored fold line. [John] tried this and found that while the metal does indeed fold along the weakened line, the aluminum tends to crack in the process. When making a line of holes instead, the metal between each hole bends nicely.

This technique does mean the finished part ends up with small perforations along each fold, but the part is mounted on the bottom of the car and [John] says that he’d have to look quite closely to notice. A little polishing goes a long way, too.

We have covered many ways to bend sheet metal and while machinery exists to do it exceedingly well, great results can be had with little more than simple tools and some patience.

Watch [John] go through the process in the video embedded below, or skip to 7:55 if you just want to see the end result.

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This Machine Makes 35mm (Almost) Film

September 11, 2026 by Jenny List 8 Comments

The revival in film photography has brought a range of specialist films to tempt the experimenter, as well as increased the popularity of loading your own cartridges. But perforating the film from blank stock has always been beyond the reach of home gamers. Now [Jon Schiereck] has done it, but not quite with film. He’s made a perforator for photographic paper, producing a strip which can be shot in a camera. It’s film, but it’s not exactly film.

The machine takes the form of a 3D printed mechanism which feeds a strip of photographic paper through a pair of punches to make the sprocket holes. In this case those holes are circular, being made by a pair of drill bits ground for the purpose, and they’re moved up and down by a crank driven by a set of gears from a hand crank or even a cordless drill. A rubber roller pulls the film forward.

It seems to be a well-thought-out machine, and you can try it yourself for free via a slightly unusual distribution medium, his Ko-Fi page. In case you’re worried about finding a slitter to make those 35mm paper strips, it seems he’s also working on a 3D printable one of those. So you can shoot on paper, and develop it just as you would a print.

If you’re further into extending what you can film through the use of a 3D printer, how about 8 mm movie film?

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Take Tool Photo, Generate Custom Gridfinity Bin

September 4, 2026 by Donald Papp 23 Comments

What if the organization and storage benefits of tool shadowing could be had and improved with a modular, semi-automated process? Tracefinity attempts that by generating custom Gridfinity bins from photos of tools, and has quite a few nifty features that are worth a look.

Maintaining a library of tools makes it easy to create project-based custom layouts.

The basic workflow is this: place one or more tools on a sheet of paper, take a photo, then upload the photo and have the system trace and save the outline and add it to a private tool library. When one is ready to create some bins, use the library of saved tool outlines to generate custom Gridfinity layouts.

If you’re unfamiliar, Gridfinity is a modular system of standardized bins and baseplates designed with 3D printing in mind, making it an ideal match for highly-customized organization tasks and a particularly natural fit for a tool-tracing system like this one.

The idea of taking a photo of a tool and generating a custom bin is a compelling one, and a couple years ago we covered a project that did just that. Tracefinity seems like a natural evolution of the idea, and includes handy features like easy design adjustments, optional magnet holes, and we really like the concept of a tool library from which individual tools are scanned once then later selected to create specific, project-based layouts.

Tracefinity takes advantage of new software capabilities like machine learning to improve and streamline the tracing process, but that doesn’t mean it relies on any external services. It can be entirely self-hosted and by default uses a local, CPU-friendly object detection model for tool tracing. There is an option to provide a API key to use Google Gemini instead, but it’s not required. It can come in handy for especially complex tool outlines or dealing with non-ideal source photos, however.