A thick, rectangular device with rounded corners is shown, with a small screen in the upper half, above a set of selection buttons.

Further Adventures In Colorimeter Hacking

September 9, 2025 by Aaron Beckendorf No comments

One of the great things about sharing hacks is that sometimes one person’s work inspires someone else to take it even further. A case in point is [Ivor]’s colorimeter hacking (parts two and three), which started with some relatively simple request spoofing to install non-stock firmware, and expanded from there until he had complete control over the hardware.

After reading [Adam Zeloof]’s work on replacing the firmware on a cosmetics spectrophotometer with general-purpose firmware, [Ivor] bought two of these colorimeters, one as a backup. He started with [Adam]’s method for updating the firmware by altering the request sent to an update server, but was only able to find the serial number from a quality-control unit. This installed the quality-control firmware, which encountered an error on the device. More searching led [Ivor] to another serial number, which gave him the base firmware, and let him dump and compare the cosmetic, quality-control, and base firmwares.

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A laboratory benchtop is shown. To the left, there is a distillation column above a collecting flask, with a tube leading from the flask to an adapter. The adapter has a frame holding a glass tube with a teflon stopper at one end, into which a smaller glass tube leads. At the other end of the larger tube is a round flask suspended in an oil bath.

Building A Rotary Evaporator For The Home Lab

September 8, 2025 by Aaron Beckendorf 7 Comments

The rotary evaporator (rotovap) rarely appears outside of well-provisioned chemistry labs. That means that despite being a fundamentally simple device, their cost generally puts them out of reach for amateur chemists. Nevertheless, they make it much more convenient to remove a solvent from a solution, so [Markus Bindhammer] designed and built his own.

Rotary evaporators have two flasks, one containing the solution to be evaporated, and one that collects the condensed solvent vapors. A rotary joint holds the evaporating flask partially immersed in a heated oil bath and connects the flask’s neck to a fixed vapor duct. Solvent vapors leave the first flask, travel through the duct, condense in a condenser, and collect in the second flask. A motor rotates the first flask, which spreads a thin layer of the solution across the flask walls, increasing the surface area and causing the liquid to evaporate more quickly.

Possibly the trickiest part of the apparatus is the rotary joint, which in [Markus]’s implementation is made of a ground-glass joint adapter surrounded by a 3D-printed gear adapter and two ball bearings. A Teflon stopper fits into one end of the adapter, the evaporation flask clips onto the other end, and a glass tube runs through the stopper. The ball bearings allow the adapter to rotate within a frame, the gear enables a motor to drive it, the Teflon stopper serves as a lubricated seal, and the non-rotating glass tube directs the solvent vapors into the condenser.

The flasks, condenser, and adapters were relatively inexpensive commercial glassware, and the frame that held them in place was primarily made of aluminium extrusion, with a few other pieces of miscellaneous hardware. In [Markus]’s test, the rotovap had no trouble evaporating isopropyl alcohol from one flask to the other.

This isn’t [Markus]’s first time turning a complex piece of scientific equipment into an amateur-accessible project, or, for that matter, making simpler equipment. He’s also taken on several major industrial chemistry processes.

Image Recognition On 0.35 Watts

September 7, 2025 by Aaron Beckendorf 23 Comments

Much of the expense of developing AI models, and much of the recent backlash to said models, stems from the massive amount of power they tend to consume. If you’re willing to sacrifice some ability and accuracy, however, you can get ever-more-decent results from minimal hardware – a tradeoff taken by the Grove Vision AI board, which runs image recognition in near-real time on only 0.35 Watts.

The heart of the board is a WiseEye processor, which combines two ARM Cortex M55 CPUs and an Ethos U55 NPU, which handles AI acceleration. The board connects to a camera module and a host device, such as another microcontroller or a more powerful computer. When the host device sends the signal, the Grove board takes a picture, runs image recognition on it, and sends the results back to the host computer. A library makes signaling over I2C convenient, but in this example [Jaryd] used a UART.

To let it run on such low-power hardware, the image recognition model needs some limits; it can run YOLO8, but it can only recognize one object, runs at a reduced resolution of 192×192, and has to be quantized down to INT8. Within those limits, though, the performance is impressive: 20-30 fps, good accuracy, and as [Jaryd] points out, less power consumption than a single key on a typical RGB-backlit keyboard. If you want another model, there are quite a few available, though apparently of varying quality. If all else fails, you can always train your own.

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A camera-based microscope is on a stand, looking down towards a slide which is held on a plastic stage. The stage is held in place by three pairs of brass rods, which run to red plastic cranks mounted to three stepper motors. On the opposite side of each crank from the connecting rod is a semicircular array of magnets.

Designing An Open Source Micro-Manipulator

September 4, 2025 by Aaron Beckendorf 21 Comments

When you think about highly-precise actuators, stepper motors probably aren’t the first device that comes to mind. However, as [Diffraction Limited]’s sub-micron capable micro-manipulator shows, they can reach extremely fine precision when paired with external feedback.

The micro-manipulator is made of a mobile platform supported by three pairs of parallel linkages, each linkage actuated by a crank mounted on a stepper motor. Rather than attaching to the structure with the more common flexures, these linkages swivel on ball joints. To minimize the effects of friction, the linkage bars are very long compared to the balls, and the wide range of allowed angles lets the manipulator’s stage move 23 mm in each direction.

To have precision as well as range, the stepper motors needed closed-loop control, which a magnetic rotary encoder provides. The encoder can divide a single rotation of a magnet into 100,000 steps, but this wasn’t enough for [Diffraction Limited]; to increase its resolution, he attached an array of alternating-polarity magnets to the rotor and positioned the magnetic encoder near these. As the rotor turns, the encoder’s local magnetic field rotates rapidly, creating a kind of magnetic gear.

A Raspberry Pi Pico 2 and three motor drivers control this creation; even here, the attention to detail is impressive. The motor drivers couldn’t have internal charge pumps or clocked logic units, since these introduce tiny timing errors and motion jitter. The carrier circuit board is double-sided and uses through-hole components for ease of replication; in a nice touch, the lower silkscreen displays pin numbers.

To test the manipulator’s capabilities, [Diffraction Limited] used it to position a chip die under a microscope. To test its accuracy and repeatability, he traced the path a slicer generated for the first layer of a Benchy, vastly scaled-down, with the manipulator. When run slowly to reduce thermal drift, it could trace a Benchy within a 20-micrometer square, and had a resolution of about 50 nanometers.

He’s already used the micro-manipulator to couple an optical fiber with a laser, but [Diffraction Limited] has some other uses in mind, including maskless lithography (perhaps putting the stepper in “wafer stepper”), electrochemical 3D printing, focus stacking, and micromachining. For another promising take on small-scale manufacturing, check out the RepRapMicron.

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In the center of the picture is a colored drawing of a man wearing a kimono, climbing out of a window. To the left and right the sides of two other pictures are just visible.

The Challenges Of Digitizing Paper Films

August 31, 2025 by Aaron Beckendorf 18 Comments

In the 1930s, as an alternative to celluloid, some Japanese companies printed films on paper (kami firumu), often in color and with synchronized 78 rpm record soundtracks. Unfortunately, between the small number produced, varying paper quality, and the destruction of World War II, few of these still survive. To keep more of these from being lost forever, a team at Bucknell University has been working on a digitization project, overcoming several technical challenges in the process.

The biggest challenge was the varying physical layout of the film. These films were printed in short strips, then glued together by hand, creating minor irregularities every few feet; the width of the film varied enough to throw off most film scanners; even the indexing holes were in inconsistent places, sometimes at the top or bottom of the fame, and above or below the frame border. The team’s solution was the Kyōrinrin scanner, named for a Japanese guardian spirit of lost papers. It uses two spools to run the lightly-tensioned film in front of a Blackmagic cinematic camera, taking a video of the continuously-moving film. To avoid damaging the film, the scanner contacts it in as few places as possible.

After taking the video, the team used a program they had written to recognize and extract still images of the individual frames, then aligned the frames and combined them into a watchable film. The team’s presented the digitized films at a number of locations, but if you’d like to see a quick sample, several of them are available on YouTube (one of which is embedded below).

This piece’s tipster pointed out some similarities to another recent article on another form of paper-based image encoding. If you don’t need to work with paper, we’ve also seen ways to scan film more accurately.

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Two sides of a business-card shaped device are shown. On the left, it’s clear that the device is about half a centimeter thick, with a large scroll wheel visible in the center. The device cover is 3D-printed in black plastic, and has cutouts to mark where three buttons ar. On the right, the underside of the device is visible. It is a black PCB, with white text giving contact information.

Building A Macro Pad Into A Business Card

August 31, 2025 by Aaron Beckendorf 10 Comments

A business card is a convenient way to share your contact information, but it’s unfortunately prone to being thrown away or forgotten. PCB business cards try to get around this problem, but while impressive, most won’t keep the recipient engaged for a very long time. [Cole Olsen]’s macro pad business card, on the other hand, might actually get regular use.

The card has three buttons and a rotary encoder as controls, with an RGB LED to indicate the card’s current mode. It can perform three sets of functions: general productivity, serving as a presentation remote, and controlling music. The scroll wheel is the main control, and can switch through windows, desktops, and tabs, page through slides, and control music volume.

The card itself is made out of a PCB, the exposed side of which contains [Cole]’s contact information, and the other side of which is covered by a 3D-printed case. As thick as it is, this might be stretching the definition of “card” a bit, but as a mechanical engineer, [Cole] did want to demonstrate some mechanical design. A nice!nano wireless keyboard development board running ZMK firmware reads the sensors and sends commands. Conveniently for a presentation remote, the card is powered by a rechargeable battery and can work wirelessly (as a side benefit, if a recipient were minded to get rid of this card, the lithium-polymer battery would probably substantially delay disposal).

[Cole] writes that he was inspired by many of the other impressive business cards we’ve covered. Some of the macro pads we’ve seen have been marvels of miniaturization in their own right.

A wrench is shown lying on a machinist’s mat. The end of the wrench holds a ratcheting wheel, on top of which are six independent metal blocks arranged into a hexagon.

Building A Shifting Ratchet Wrench

August 30, 2025 by Aaron Beckendorf 13 Comments

Convenient though they may be, [Trevor Faber] found some serious shortcomings in shifting spanners: their worm gears are slow to adjust and prone to jamming, they don’t apply even force to all faces of a bolt head, and without a ratchet, they’re rather slow. To overcome these limitations, he designed his own adjustable ratchet wrench.

The adjustment mechanism is based on a pair of plates with opposing slots; the wrench faces are mounted on pins which fit into these slots, and one plate rotates relative to the other, the faces slide inwards or outwards. A significant advantage of this design is that, since one plate is attached to the wrench’s handle, some of the torque applied to the wrench tightens its grip on the bolt. To let the wrench loosen as well as tighten bolts, [Trevor] simply mirrored the mechanism on the other side of the wrench. Manufacturing proved to be quite a challenge: laser cutting wasn’t precise enough for critical parts, and CNC control interpolation resulted in some rough curves which caused the mechanism to bind, but after numerous iterations, [Trevor] finally got a working tool.

To use the wrench, you twist an outer ring to open the jaws, place them over the bolt, then let them snap shut. One nice touch is that you can close this wrench over a bolt, let go of it, and do something else without the wrench falling off the bolt. Recessed bolts were a bit of an issue, but a chamfer ought to improve this. It probably won’t be replacing your socket set, but it looks like it could make the odd job more enjoyable.

If you prefer a more conventional shifting wrench, you can make a miniature out of an M20 nut. It’s also possible to make a shifting Allen wrench.

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