Big Chemistry: Catalysts

I was fascinated by the idea of jet packs when I was a kid. They were sci-fi magic, and the idea that you could strap into an oversized backpack wrapped in tinfoil and fly around was very enticing. Better still was when I learned that these things weren’t powered by complicated rockets but by plain hydrogen peroxide, which violently decomposes into water and oxygen when it comes in contact with a metal like silver or platinum. Of course I ran right to the medicine cabinet to fetch a bottle of peroxide to drip on a spoon from my mother’s good silverware set. Needless to say, I was sorely disappointed by the results.

My little impromptu experiment went wrong in many ways, not least because the old bottle of peroxide I used probably had little of the reactive compound left in it. Given enough time, the decomposition of peroxide will happen all by itself. To be useful in a jet pack, this reaction has to proceed much, much faster, which was what the silver was for. The silver (or rather, a coating of samarium nitrate on the silver) acted as a catalyst that vastly increased the rate of peroxide decomposition, enough to produce jets of steam and oxygen with enough thrust to propel the wearer into the air. Using 90% pure peroxide would have helped too.

As it is for jet packs, so it is with industrial chemistry. Bulk chemical processes can rarely be left to their own devices, as some reactions proceed so slowly that they’d be commercially infeasible. Catalysts are the key to the chemistry we need to keep the world running, and reactors full of them are a major feature of many of the processes of Big Chemistry.

Continue reading “Big Chemistry: Catalysts”

Google Open Sources PebbleOS: New Pebble Device In Development

The Pebble smartwatch was introduced in 2012 as part of a Kickstarter campaign and saw moderate success before the company behind it got bought out by Fitbit. Although a group of enthusiasts kept their Pebble devices alive, including via the alternate Rebble project for online services, it seemed that no new Pebble devices would grace this Earth. However, we now got a flurry of Pebble updates, with Google, the current owner of Fitbit, open sourcing the PebbleOS source, and [Eric Migicovsky] as the original Pebble founder announcing new Pebble watches.

These new Pebble watches would be very much like the original Pebble, though switching from a memory LCD to an e-paper screen but keeping compatibility with the original Pebble watch and its hackability. Currently there’s just a rePebble site where you can sign up for announcements. Over at the Rebble project people are understandably excited, with the PebbleOS source available on GitHub.

A lot of work still remains, of course. The Apache 2.0-licensed PebbleOS source was stripped of everything from fonts to the voice codec and Bluetooth stack, and of course bootstrapping whole new hardware production will require serious investment. Even so, for lovers of smart watches that work with modern-day smartphones, featuring an always-on display and amazing battery life the future has never been more bright.

Thanks to [Will0] for the tip.

A Little Pigment Helps With Laser Glass Engraving

The range of materials suitable for even the cheapest laser cutter is part of what makes them such versatile and desirable tools. As long as you temper your expectations, there’s plenty of material to cut with your 40 watt CO2 laser or at least engrave—just not glass; that’s a tough one.

Or is it? According to [rschoenm], all it takes to engrave glass is a special coating. The recipe is easy: two parts white PVA glue, one part water, and two parts powdered titanium dioxide. The TiO2 is the important part; it changes color when heated by the laser, forming a deep black line that adheres to the surface of the glass. The glue is just there as a binder to keep the TiO2 from being blasted away by the air assist, and the water thins out the goop for easy spreading with a paintbrush. Apply one or two coats, let it dry, and blast away. Vector files work better than raster files, and you’ll probably have to play with settings to get optimal results.

With plain float glass, [rschoenm] gets really nice results. He also tried ceramic tile and achieved similar results, although he says he had to add a drop or two of food coloring to the coating so he could see it against the white tile surface. Acrylic didn’t work, but there are other methods to do that.

Continue reading “A Little Pigment Helps With Laser Glass Engraving”

Film Capacitors Can Go In The Wrong Way Round? Who Knew!

You can work with a part for many decades, and still learn something new about it. At least we can, and we don’t mind admitting it. Take film capacitors — we all know they aren’t a polarized part like an electrolytic capacitor is, but as [TheDannVal] points out, that doesn’t mean both their leads are the same.

This might sound counterintuitive, but if you consider for a moment their construction it makes sense. A film capacitor is made from two strips of foil with a strip of plastic film between then, rolled up tightly into a cylinder. One of the pieces of foil that forms one side of the capacitor ends up on the outside of the cylinder, and thus forms the shield for the other. Thus if that side isn’t connected to the lower impedance side of whichever circuitry it resides in, it can pick up noise, while the inside strip of foil can not. It’s so obvious when demonstrated, but we have to admit to never having considered it before. Some film capacitors have a line marked on them to denote the connection forming the shield, for those that don’t he provides a couple of methods for detecting it.

The full video is below the break, and maybe you too can now pay attention to your capacitors for lower noise audio circuitry.

Continue reading “Film Capacitors Can Go In The Wrong Way Round? Who Knew!”

DIY Probe Clamps To Ease Your PCB Work

Those of us familiar with PCB work would agree that anything that helps hold probes secure and hands-free to components, traces, or test points is worth looking at. That’s where [2048bits]’ snap probe design comes in. With a little additional and inexpensive hardware, one can have all the hands-free probe clamps one’s workbench can fit!

That first link is where you’ll find a list of required hardware and the CAD files (in .step format) for the probe itself. The obvious approach to making the pieces would be to 3D print them, but we notice the design — while attractive — looks like a challenging print due to the features. We’re not the only ones to see that, and happily there’s already a remix by [user_2299476772] aimed at keeping the essential features while making them easier to print.

If you’re taking a DIY approach to PCB probes, we’d like to remind you that one of our readers discovered dental burrs make absolutely fantastic, non-slip probe tips. This seems like a good opportunity to combine two ideas, and having the CAD files for the probe clamp means modification is straightforward. Let us know on the tips line if you get something working!

[via Hackster]

A Low Voltage Solder Gun From Scratch

We’re used to those high voltage projects which use a self-oscillating transformer circuit with a TV flyback winding, and we have even at times railed against them for their inefficiency compared to a real flyback circuit using the same parts. But what happens if the same idea is used to create a low voltage instead of a high one? [D. Creative] has a soldering gun project doing just this, making a low voltage at a very high current.

The video of the project is below the break, and while electrically it’s nothing unexpected, we’re taken by the quality of the build. All the parts come from scrap electronics, the main transformer is three ferrite cores with a piece of copper busbar as the secondary. The circuitry is built dead bug style, and it’s housed in a gun-style case made by hand from sheet Perspex. It takes 12 volt power from a laptop power supply, and feeds it to the oscillator which is perched up at the back of the device. The transformer fits in the “barrel”, and a pair of large capacitors fit in the handle. We expect it to get hot, but the duty cycle on these devices in use is probably low enough to keep it from melting.

We like anything that uses scrap parts to make something useful, and we’re particularly taken with the casing of this one. It looks as though the parts come from old switch mode power supplies, something we’ve been known to rob ourselves.

Continue reading “A Low Voltage Solder Gun From Scratch”

New Open Source DeepSeek V3 Language Model Making Waves

In the world of large language models (LLMs) there tend to be relatively few upsets ever since OpenAI barged onto the scene with its transformer-based GPT models a few years ago, yet now it seems that Chinese company DeepSeek has upended the status quo. Its new DeepSeek-V3 model is not only open source, it also claims to have been trained for only a fraction of the effort required by competing models, while performing significantly better.

The full training of DeepSeek-V3’s 671B parameters is claimed to have only taken 2.788 M hours on NVidia H800 (Hopper-based) GPUs, which is almost a factor of ten less than others. Naturally this has the LLM industry somewhat up in a mild panic, but for those who are not investors in LLM companies or NVidia can partake in this new OSS model that has been released under the MIT license, along with the DeepSeek-R1 reasoning model.

Both of these models can be run locally, using both AMD and NVidia GPUs, as well as using the online APIs. If these models do indeed perform as efficiently as claimed, they stand to massively reduce the hardware and power required to not only train but also query LLMs.