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Creating Lookalike Valves With Resin Casting

November 21, 2019 by 10 Comments

Valves (tubes) certainly have a die hard fan base in the electronic community, praised for their warm sound, desirable distortion characteristics and attractive aesthetic. However, sometimes you just want the look of a valve for a prop or a toy, without actually needing the functionality. For those cases, this project from [Ajaxjones] might be just the ticket.

The build consists of taking an existing valve, combining it with a 3D printed base, and using this to create a silicone mould. 3D printed parts and dressmaker’s pins are then used to create the internal parts of the valve, and are inserted into the mould. Clear resin is then degassed, and poured into the mould to create the part. Once cured, the part is removed and the base painted to complete the look. An LED is then installed into a void in the base to give the piece a warm glow as you’d expect.

It’s a simple tutorial to producing high-quality clear plastic parts, and one that should prove useful to many prop builders and cosplayers alike. If you’re wanting to take your resin game to the next level, consider trying some overmolded parts. Video after the break.

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Fast Fresnel Hack Embiggens The Smallest Of Heads

November 20, 2019 by 17 Comments

Aside from frightening small children, we have absolutely no idea why anyone would need a face-magnifying headpiece. But the video below gives us a chuckle every time we see it, and we figure a good laugh that incorporates a quick optics hack is worth a look.

When he’s not playing geek in a box, [Curious Marc]’s videos usually have more of a retrocomputing theme, like his recent conversion of a vintage terminal to a character set from a made-up language, or helping to revive an Apollo Guidance Computer. Given gems like those, we were surprised to learn that [Marc]’s background is physics – optics, to be precise – and that he studied at École Polytechnique, the same school famed physicist Augustin-Jean Fresnel attended. Which fits right into this build since it features one of those large, plastic Fresnel lenses. After a fascinating detour into the history of Fresnel’s namesake lens, [Marc] proceeds with the build.

It’s simplicity itself – a box big enough to wear on the head with one end replaced by the Fresnel lens. A strip of LEDs – warm white, please, lest the wearer takes on a deathly pall – lines the edge of the box just behind the lens. If you want to get fancy, maybe attaching a hard-hat suspension piece would make it more wearable, but even as is it’s just a hoot to see someone with a magnified and distorted head walking around. One probably should be careful not to look at the sun while wearing this, however, for reasons that become apparent beginning at the 3:24 mark of the video.

Thanks to [Marc] for perhaps the oddest YouTube face-reveal yet, and for a great idea for a quick cosplay hack.

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This RGB Tree Has Its Roots In A PCB

November 18, 2019 by 1 Comment

[Paczkaexpress]’s RGB tree is a mix of clever building techniques and artistic form that come together into quite a beautiful sculpture.

The branches of his tree are made from strands of enameled copper wire capped with an RGB LED and terminated in a female header. The separate wires are all wound and sculpted into the form of a tree. The wire is covered in a very thin layer of plastic, which we highly recommend observing under a microscope, that allow it to maintain a uniform and reflective copper color without shorting, adding to the effect.

The part we found an especially pleasing mix of form and function was how the “roots” of the tree clicked home in the PCB base. The PCB holds the STM32, power components, and an LED Driver. It doesn’t hide how the magic works, and the tree really does get its nutrients from the soil it’s planted in. This would be a fun kit to build. Very clever and you can see the final effect after the break.

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A Self-Expanding PWM Driver

November 15, 2019 by 8 Comments

For smaller microcontrollers, having enough outputs for the job is sometimes a challenge. A common solution is to do some sort of multiplexing with the available outputs or perhaps something more advanced such as Charlieplexing, but another good option is to use a specialized driver board. What’s even better is if you can daisy chain driver boards to get even more outputs.

[Eric] has been working on a 16 channel LED project but first wanted to build a driver board with 8 channels. Before building a full 16 channel version he realized that he could take the same 8 channel board, make a mirror image of it, and attach it underneath the first board with headers in order to double the number of channels available. Without having to build a separate 16-channel board, this shortcut saved [Eric] some time and a great deal of effort.

This is a great example of working smarter, not harder. Each of the 8 or 16 channels has full PWM support as well to support PWM dimming, and a similar board could be built for motor control as well. It’s a good illustration of how good design can end up working for you as well. And if you need even more outputs, Charlieplexing is one way to get them.

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Tindie Seller Reviews A Knock-Off Of His Own Product

November 13, 2019 by 66 Comments

If imitation is the sincerest form of flattery, online creators are being sincerely flattered at an alarming rate these days. We Hackaday scribes see it all the time, as straight copy-pastes of our articles turn up on other websites under different bylines. It’s annoying, but given prevailing attitudes toward intellectual property rights, there’s very little point in getting upset about it anymore. But what if it’s hardware that’s being infringed upon?

Hacker and Tindie store proprietor [Brian Lough] recently ran into this problem with one of his products, but rather than get upset, he did a remarkably fair and thoughtful review of the knock-off. The board in question, a D1 Mini Matrix Shield, makes it a snap to use LED matrix panels in projects like his Tetris-themed YouTube sub counter. The knock-off came via Ali Express, with the most “flattering” aspect being the copy and the images on the Ali Express listing, some of which are pulled straight from [Brian]’s Tindie store. While the board’s layout is different, it’s pretty clear that it was strongly inspired by the original. And the changes they did make – like terminal choices and undersizing some traces – only serve to lower the quality of the knock-off. Surely this was a cost-cutting move, so they could undercut sales of the original, right? Apparently not – the knock off is more expensive. Yes, [Brian]’s board is a kit and the imitator is fully assembled, but it still begs the question of why?

Hats off to [Brian] for not only making a useful product, but for taking the time to engineer it properly and having the ambition to put it on the market. It’s a pity that someone felt the need to steal his work, but it seems to be a rite of passage these days.

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Ambitious LED Cube Provides Endless Video Game Scrolling; Plays Castlevania

November 4, 2019 by 12 Comments

LED cubes are all the rage right now, and rightly so given the amount of work that goes into them and the interesting things people find to do with them. Not content to make yet another position-sensitive display or an abstract design, though, [Greig Stewart] opted for something a bit more ambitious: an LED cube with a playable game of Castlevania.

As ambitious projects often do, this one required leveraging the previous art, some of which we’ve featured before. [Greig] pulled inspiration and information from cube builders like [polyfloyd], [Greg Davill], and [kbob] to put the six 64-LED matrix panels to work. Getting the structural elements figured out was an early stumbling block, but [Greig] pulled it off with 3D-printed brackets and a hinge that’s a work of art in itself; the whole thing looks like something the Borg would have built. The Raspberry Pi inside made a Gameboy emulator possible, and his first stab at it was to have six different games running at once, one on each panel. He settled on just one game, the classic side-scroller Castlevania, played on just four of the panels. Some wizardry was required to de-scroll the game so that the character walks around the cube rather than having the background scroll; you can check out the results in the clip below.

Currently, the cube sits on a lazy susan with a small motor controlling the swiveling in response to a foot control. [Greig] wants to put the motor under control of the game so that physical scrolling is synced with gameplay; we heartily endorse that plan and look forward to the results.

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The Basics Of Persistence Of Vision Projects

October 29, 2019 by 6 Comments

Persistence of Vision (POV) is a curious part of the human visual system. It’s the effect by which the perception of an image lingers after light has stopped entering the eye. It’s why a spinning propeller appears as a disc, and why a burning sparkler appears to leave a trail in the air. It’s also commonly used as a display technology, where a series of flashing LEDs can be used to create messages that appear to float in the air. POV displays are a popular microcontroller project, and today, we’ll explore the basic techniques and skills required in such builds.

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