Perovskite Solar Cell Crystals See The Invisible

September 16, 2025 by Heidi Ulrich 14 Comments

A new kind of ‘camera’ is poking at the invisible world of the human body – and it’s made from the same weird crystals that once shook up solar energy. Researchers at Northwestern University and Soochow University have built the first perovskite-based gamma-ray detector that actually works for nuclear medicine imaging, like SPECT scans. This hack is unusual because it takes a once-experimental lab material and shows it can replace multimillion-dollar detectors in real-world hospitals.

Current medical scanners rely on CZT or NaI detectors. CZT is pricey and cracks like ice on a frozen lake. NaI is cheaper, but fuzzy – like photographing a cat through steamed-up glass. Perovskites, however, are easier to grow, cheaper to process, and now proven to detect single photons with record-breaking precision. The team pixelated their crystal like a smartphone camera sensor and pulled crisp 3D images out of faint radiation traces. The payoff: sharper scans, lower radiation doses, and tech that could spread beyond rich clinics.

Perovskite was once typecast as a ‘solar cell wonder,’ but now it’s mutating into a disruptive medical eye. A hack in the truest sense: re-purposing physics for life-saving clarity.

Serious Chemical Threat Sniffer On A Budget

September 16, 2025 by Heidi Ulrich 40 Comments

Chemical warfare detection was never supposed to be a hobbyist project. Yet here we are: Air Quality Guardian by [debdoot], the self-proclaimed world’s first open source chemical threat detection system, claims to pack lab-grade sensing into an ESP32-based build for less than $100. Compare that with $10,000+ black-box hardware and you see why this is worth trying at home, even if this project might not have the nut cracked just yet.

Unlike your air monitor from IKEA, the device aims to analyze raw gas sensor resistance – ohm-level data most devices throw away – combined with temporal spikes, humidity correlations, and a database of 35+ signatures. Of course, there is a lot of work to be done here on the calibration side, and we don’t have any chemical warfare agents on hand to test against, so we have no idea how well it works, and we’d expect false positives. Still, the idea of taking a more granular look at the data coming off the sensor may bear some fruit.

(Editor’s note: edited with a hefty dash of skeptical salt.)

Featured Image by Arjun Lama on Unsplash

E-Waste And Waste Oil Combine To Make Silver

September 14, 2025 by Tyler August 12 Comments

As the saying goes, “if it can’t be grown, it has to be mined”– but what about all the metals that have already been wrested from the bosom of the Earth? Once used, they can be recycled– or as this paper charmingly puts it, become ore for “urban mining” techniques. The technique under discussion in the Chemical Engineering Journal is one that extracts metallic silver from e-waste using fatty acids and hydrogen peroxide.

This “graphical abstract” gives the rough idea.

Right now, recycling makes up about 17% of the global silver supply. As rich sources of ore dry up, and the world moves to more sustainable footing, that number can only go up. Recycling e-waste already happens, of course, but in messy, dangerous processes that are generally banned in the developed world. (Like open burning, of plastic, gross.)

This paper describes a “green” process that even the most fervant granola-munching NIMBY wouldn’t mind have in their neighborhood: hot fatty acids (AKA oil) are used as an organic solvent to dissolve metals from PCB and wire. The paper mentions sourcing the solvent from waste sunflower, safflower or canola oil. As you might imagine, most metals, silver included, are not terribly soluble in sunflower oil, but a little refining and the addition of 30% hydrogen peroxide changes that equation.

More than just Ag is picked up in this process, but the oils do select for silver over other metals. The paper presents a way to then selectively precipitate out the silver as silver oleate using ethanol and flourescent light. The oleate compound can then be easily washed and burnt to produce pure silver.

The authors of the paper take the time to demonstrate the process on a silver-plated keyboard connector, so there is proof of concept on real e-waste. Selecting for silver means leaving behind gold, however, so we’re not sure how the economics of this method will stack up.

Of course, when Hackaday talks about recycling e-waste, it’s usually more on the “reuse” part of “reduce, reuse, recycle”. After all, one man’s e-waste is another man’s parts bin–or priceless historical artifact.

Thanks to [Brian] for the tip.Your tips can be easily recycled into Hackaday posts through an environmentally-friendly process via our tipsline.

How Strong Of A Redbull Can You Make?

September 12, 2025 by Fenix Guthrie 38 Comments

Energy drinks are a staple of those who want to get awake and energetic in a hurry. But what if said energy is not in enough of a hurry for your taste? After coming across a thrice concentrated energy drink, [Nile Blue] decided to make a 100 times concentrated Redbull.

Energy drinks largely consist of water with caffeine, flavoring and sugar dissolved inside. Because a solution can only be so strong, so instead of normal Redbull, a sugar free variant was used. All 100 cans were gathered into a bucket to dry the mixture, but first, it had to be de-carbonated. By attaching a water agitator to a drill, all the carbon dioxide diffused in the water fell out of solution. A little was lost, but the process worked extremely well.

Continue reading “How Strong Of A Redbull Can You Make?” →

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.

Restoring A Cheap Fume Hood

September 5, 2025 by Fenix Guthrie 8 Comments

Semiconductor fabrication is complicated requiring nasty chemicals for everything from dopants to etchants. Working with such chemicals at home is dangerous and after releasing hydrochloride acid fumes into his lab, [ProjectsInFlight] decided the time was right to get one for a mere $200.

I can hear the readers down in the comments already saying, “why not just make one?” But a properly engineered fume hood provides laminar flow which absolutely ensures no leakage of fumes out of the hood. However, such proper engineering comes with an impressive price tag, so the used market was the only choice. This is less dangerous then it sounds as companies are required by both OSHA and the EPA to clean their fume hoods before removal, so no chemical residue should remain after purchase.

Continue reading “Restoring A Cheap Fume Hood” →

Applying Thermal Lining To Rocket Tubes Requires A Monstrous DIY Spin-caster

September 2, 2025 by Donald Papp 18 Comments

[BPS.space] takes model rocketry seriously, and their rockets tend to get bigger and bigger. If there’s one thing that comes with the territory in DIY rocketry, it’s the constant need to solve new problems.

Coating the inside of a tube evenly with a thick, goopy layer before it cures isn’t easy.

One such problem is how to coat the inside of a rocket motor tube with a thermal liner, and their solution is a machine they made and called the Limb Remover 6000 on account of its ability to spin an 18 kg metal tube at up to 1,000 rpm which is certainly enough to, well, you know.

One problem is that the mixture for the thermal liner is extremely thick and goopy, and doesn’t pour very well. To get an even layer inside a tube requires spin-casting, which is a process of putting the goop inside, then spinning the tube at high speed to evenly distribute the goop before it cures. While conceptually straightforward, this particular spin-casting job has a few troublesome difficulties.

For one thing, the uncured thermal liner is so thick and flows so poorly that it can’t simply be poured in to let the spinning do all the work of spreading it out. It needs to be distributed as evenly as possible up front, and [BPS.space] achieves that with what is essentially a giant syringe that is moved the length of the tube while extruding the uncured liner while the clock is ticking. If that sounds like a cumbersome job, that’s because it is.

The first attempt ended up scrapped but helped identify a number of shortcomings. After making various improvements the second went much better and was successfully tested with a 12 second burn that left the tube not only un-melted, but cool enough to briefly touch after a few minutes. There are still improvements to be made, but overall it’s one less problem to solve.

We’re always happy to see progress from [BPS.space], especially milestones like successfully (and propulsively) landing a model rocket, and we look forward to many more.

Continue reading “Applying Thermal Lining To Rocket Tubes Requires A Monstrous DIY Spin-caster” →