This Tiny Steam Engine Takes A Watchmaker’s Skill To Build

September 9, 2024 by Dan Maloney 30 Comments

When your steam engine build requires multiple microscopes, including those of the scanning electron variety, you know you’re building something really, really tiny.

All of the usual tiny superlatives and comparisons apply to [Chronova Engineering]’s latest effort — fits on a pencil eraser, don’t sneeze while you’re working on it or you’ll never find it. If we were to put the footprint of this engine into SMD context, we’d say it’s around a 2010 or so. As one would expect, the design is minimalistic, with no room for traditional bearings or valves. The piston and connecting rod are one piece, meaning the cylinder must pivot, which provides a clever way of switching between intake and exhaust. Tiny crankshaft, tiny flywheel. Everything you’d associate with a steam engine is there, but just barely.

The tooling needed to accomplish this feat is pretty impressive too. [Chronova] are no strangers to precision work, but this is a step beyond. Almost everything was done on a watchmaker’s lathe with a milling attachment and a microscope assist. For the main body of the engine, a pantograph engraving machine was enlisted to scale a 3D printed template down tenfold. Drill bits in the 0.3 mm range didn’t fare too well against annealed tool steel, which is where the scanning electron microscope came into play. It revealed brittle fractures in the carbide tool, which prompted a dive down the rabbit hole of micro-machining and a switch to high-speed steel tooling.

It all worked in the end, enough so that the engine managed 42,000 RPM on a test with compressed air. We eagerly await the equally tiny boiler for a live steam test.

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The Science Of Coating Steel

September 9, 2024 by Al Williams 6 Comments

[Breaking Taps] has a look at “parkerization” — a process to coat steel to prevent rust. While you commonly see this finish in firearms, it is usable anywhere you need some protection for steel parts. The process is relatively easy. It does require heat and a special manganese solution made for the purpose. You scuff up the surface of the steel and degrease and wash it.

Once the part is ready, you insert the part in hot solution which is manganese and phosphoric acid. Rinse and displace the water and you are ready to oil the part.

But what we really liked was the electron micrographs of the steel before and after the process. The phosphates formed in the solution cover the iron and hold oil to prevent oxidization. However, the first attempt wasn’t uniform so it wouldn’t work as well. [Breaking Taps] thinks it was a failure to rough up the piece sufficiently before starting. He also raised the temperature of the bath and got a better, but not perfect, result.

We miss having an electron microscope at work and we really want one at home! The last fun coating project we remember used copper in a strange and wonderful way.

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Multi-Material Printing Enables Low Cost Silicone Prototypes

September 4, 2024 by Tom Nardi 11 Comments

While it’s the ideal choice for mass production, injection molding is simply no good for prototyping. The molds are expensive and time-consuming make, so unless you’ve got the funding to burn tens of thousands of dollars on producing new ones each time you make a tweak to your design, they’re the kind of thing you don’t want to have made until you’re absolutely sure everything is dialed in and ready. So how do you get to that point without breaking the bank?

That’s not always an easy question, but if you’re working with silicone parts, the team at OpenAeros thinks they might have a solution for you. As demonstrated through their OpenRespirator project, the team has developed a method of 3D printing single-use molds suitable for large silicone parts that they’re calling Digital-to-Silicone (D2S).

In the video below, [Aaron] and [Jon] explain that they started off by simply printing injection molds in the traditional style. This worked, but the molds can get quite complex, and the time and effort necessary to design and print them wasn’t a great fit for their iterative development cycle. They wanted to be able to do from design to prototype in a day, not a week.

Eventually they realized that if they printed the mold out of a water-soluble filament, they could simplify its design greatly. They’ve documented the design process in detail, but the short version is that you essentially subtract the 3D model of the design you want to produce from a solid shape in your CAD package, and add a few holes for injecting the silicone. Once the silicone has cured, the mold can be dissolved away in warm water to reveal the finished part.

They then took this concept a step further. Thanks to the multi-material capabilities offered by some of the latest 3D printers, it’s possible to print structures within the mold. Once the silicone is injected, these structures can become part of the finished part. For the OpenRespirator, this lets them add PETG stiffening rings around where the filters to snap into the silicone mask body.

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CCFL Scanner Bulb Makes A Cool Desk Lamp

August 31, 2024 by Alexander Rowsell 12 Comments

The bulbs inside scanners (before transitioning to LED, anyway) were cold cathode fluorescent tubes that emit a fairly wide bandwidth of light. They were purpose-built to produce a very specific type and shape of light, but [Julius Curt] has taken this in a new, upcycled direction. Instead of just producing light, the light itself is also part of the aesthetic. A very cool 3D printed case houses the bulb and power supply and smartly hides the connecting wires to achieve a very clean look.

Part of the design involves adding a DC-DC converter before the lamp driver, allowing fading of the light. This isn’t anything new in lamps, but [Julius] noticed an interesting effect when dimming the vertically oriented lamp: as the power was reduced, the column of light would start to extinguish from one end, leading to an elongated teardrop-shaped light source.

This leads to a very interesting look, and the neat case design leads to an extremely unique lamp! The emitted light’s color temperature seems to vary a bit as the voltage drops, going from what appears to be a pretty cold white to a slightly warmer tone.

The design process is detailed on the project page, with a quick look at the CAD design process for the case. A neat touch was using a greeble (part of a coffee grinder) to add some different textures and break up the plastic-only look. That’s one we’ll have to note in our design books!

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Make Your Own Point Contact Transistor

August 31, 2024 by Jenny List 22 Comments

Beyond the power variant, it sometimes seems as though we rarely encounter a discrete transistor these days, such has been the advance of integrated electronics. But they have a rich history, going back through the silicon era to germanium junction transistors, and thence to the original devices. if you’ve ever looked at the symbol for a transistor and wondered what it represents, it’s a picture of those earliest transistors, which were point contact devices. A piece of germanium as the base had two metal electrodes touching it as the emitter or collector, and as [Marcin Marciniak] shows us, you can make one yourself (Polish language, Google Translate link).

These home made transistors sacrifice a point contact diode to get the small chip of germanium, and form the other two electrodes with metal foil glued to paper. Given that germanium point contact diodes are themselves a rarity these days we’re guessing that some of you will be wincing at that. The video below is in Polish so you’ll have to enable YouTube’s translation if you’re an Anglophone — but we understand that the contact has to be made by passing a current through it, and is then secured with a drop of beeswax.

A slight surprise comes in how point contact transistors are used, unlike today’s devices their gain in common emitter mode was so poor that they took instead a common base configuration. There’s a picture of a project using three of them, a very period radio receiver with bulky transformers between all stages.

If you’re interested in more tales of home made early transistors, read our feature on Rufus Turner.

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Why Use A Sensor When A Pseudo-Sensor Will Do?

August 28, 2024 by Lewin Day 30 Comments

Usually, when you need to sense something in a project, the answers are straightforward. Want to sense air temperature? There’s a sensor for that. Particulate content in the air? There’s a sensor for that, too. Someone sneaking up on you? Get yourself some passive infrared sensors (PIRs) and maybe a smart camera just to be sure.

But sometimes you can be sneaky instead, saving the cost of a sensor by using alternative techniques. Perhaps there’s a way to use the hardware you already have to determine what you need. Maybe you can use statistical methods to calculate the quantity you’re looking for from other measurements.

Today, we’ll examine a great example of a “pseudo-sensor” build in an existing commercial device, and examine how these techniques are often put to good use in industry.

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Supercon 2024: Show Off Your Unique Display Tech

August 26, 2024 by Tom Nardi 4 Comments

If there’s a constant in the world of electronics, it’s change. Advancements and breakthroughs mean that what was once state-of-the-art all too soon finds itself collecting dust. But there are exceptions. Perhaps because they’re so much more visible to us than other types of components, many styles of displays have managed to carve out their own niche and stick around. Even for the display types that we no longer see used in consumer hardware, their unique aesthetic qualities often live on in media, art, and design.

This year, to coincide with Hackaday Supercon, the folks at Supplyframe’s DesignLab want to pay tribute to display technology past and present with a special exhibit — and they need your help to make it possible. If you have a display you’d like to show off, fill out this form and tell them what you’ve got. Just be sure to do it by September 16th.

For the larger specimens, it would be ideal if you’re somewhat local to Southern California, but otherwise, they’re looking for submissions from all over the world. The exhibit will open on the first day of Supercon and run throughout November.

Don’t worry. They’re only looking to raid your parts bin temporarily. Any hardware sent in to be part of the exhibit will be considered on loan, and they’ll make sure it gets back to where it belongs by January 31st, 2025. The goal is to show the displays on and operational, so in most cases, that’s going to mean sending over a complete device. But if it’s possible to isolate the display itself and still demonstrate what it would look like in operation, sending along just the bare display is an option. Continue reading “Supercon 2024: Show Off Your Unique Display Tech” →