Edge-lit Pendants Show Two Layers Are Better Than One

Engraved acrylic lights up nicely with LED lighting. Simply engrave clear acrylic with a laser engraver, then edge-light the acrylic and watch the engraving light up. This badge made by [Solarbotics] shows how they used this principle when creating some pendants for an event that performed particularly well in the dark.

The pendants they created have two engraved acrylic panels each, and that’s about it. Two LEDs and a CR2032 battery nestle into pre-cut holes, and the engraved sides are placed face-to-face, so the outer surfaces of the pendant are smooth. By using some color-cycling RGB LEDs on one panel and blue LEDs on the other panel, the effect is that of an edge-lit outer design with a central element that slowly changes color separately from the rest of the pendant.

The design stacks the LED leads and coin cells in such a way that a simple wrap of tape not only secures things physically, but also takes care of making a good electrical connection. No soldering or connectors of any kind required. [Solarbotics] found that CR2032 cells would last anywhere between a couple of days to a week, depending on the supplier.

This design is great for using a minimum of materials, but if that’s not a priority it’s possible to go much further with the concept. Multiple layers of edge-lit acrylic were used to make numeric 0-9 display modules as well as a full-color image.

 

Make Your Own Reed Switches

[Lucid Science] shows us how to make some simple reed switches. Reed switches are simple components that detect a magnetic field and can close or open a circuit once detected. While not really a thing of beauty, these DIY reed switches should help you out if you just can’t wait to order some or you fancied trying your hands at making some components from scratch.

Reed switches normally come in very small form factors so if you need something small then this may not be for you however the video does show you on a macro scale the fundamental workings of a reed switch. To make your own reed switch you need only a few parts: some copper, enamelled wire and magnets. They really are simple devices however sometimes it’s easy to overlook how simple some things are when they are so small that you can’t really see how they work.

Making your own components from scratch is probably the best way to understand the inner workings of said component. In the past we have seen some pretty awesome self built components from these beautiful DIY Nixie tubes to even making your own LEDs

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DIY Illuminator For UV Fluorescence Photography

The image shown is the mineral Hackmanite, which fluoresces under ultraviolet lighting. However, not all UV is created equal, and that makes a difference if you’re into UV imaging. The image for this article is from [David Prutchi] and shows the striking results of using different wavelengths of UV. [David] goes into detail on how to make your own DIY Long, Medium, and Short-wave UV Illuminator complete with part numbers and wiring diagram. The device isn’t particularly complicated; the real work was determining the exact part numbers and models of lamp, filters, and ballasts required to get the correct results. [David] has done that work and shared it for anyone interested in serious UV fluorescence photography, along with a white paper on the process.

We’ve seen [David]’s work before. We featured his DIY short-wave UV imager in the past, and his DOLPi camera project was a 2015 Hackaday Prize finalist. It’s clear he really knows his stuff, and genuinely enjoys sharing his discoveries and work.

Push Button, Receive Beverage!

Here’s a rec-room ready hack: an automatic drink dispenser.

[truebassB]’s dispenser operates around a 555 timer, adjusted by a potentiometer. Push a button and a cup pours in a few seconds, or hold the other button to dispense as much as you want.

The dispenser is made from MDF and particle board glued together, with some LEDs and paper prints to spruce it up. Just don’t forget a small spill sink for any miscalculated pours. You needn’t fret over the internals either, as the parts are easily acquired: a pair of momentary switches, a 12V micro air pump, a brass nozzle, food-safe pvc tube,  a custom 555 timing circuit — otherwise readily available online — a toggle switch, a power supply plug plus adapter and a 12V battery.

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Microorganisms Can’t Hide From DropoScope

The DropoScope is a water-drop projector that works by projecting a laser through a drop of water, ideally dirty water crawling with microorganisms. With the right adjustments, a bright spot of light is projected onto a nearby wall, revealing a magnified image of the tiny animals within. Single celled organisms show up only as dark spots, but larger creatures like mosquito larvae exhibit definite structure and detail.

While simple in concept and requiring nothing more high-tech than a syringe and a laser pointer, getting useful results can require a lot of fiddly adjustment. But all that is a thing of the past for anyone with access to a laser cutter, thanks to [ingggis].  His design for a laser-cut a fixture lets anyone make and effortlessly adjust their own water-drop projector.

If you’d like to see some microorganisms in action, embedded below is video from a different water-drop projector (one identical in operation, but not lucky enough to benefit from [ingggis]’s design.)

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Improved Game Tokens With Laser Cutting And Clever Design

[Martin Raynsford] is a prolific project maker, especially when it comes to using a laser cutter. These laser-cut token counters for the board game Tigris & Euphrates demonstrate some clever design, and show that some simple touches can make a big difference.

In the digital version of the game, the tokens conveniently display a number representing their total power value. [Martin] liked this feature, and set out to design a replacement token for the tabletop version that could display a number while still keeping the aesthetic of the originals. The tokens were designed as a dial with a small cutout window to show a number, but the surface of the token showing color and icon is still mostly unchanged.

Magnets hold the top and bottom together, and because of the small size of the assembly, no detents are needed. Friction is enough to keep things from moving unintentionally. The second noteworthy design feature is the material for the top layer of the token. This layer is made from 0.8 mm birch plywood; a nice and thin top layer means a wider viewing angle because the number is nearer to the surface. If the top layer were thicker, the number would be recessed and harder to see.

[Martin] made the design file available should anyone wish to try it out. No stranger to games, he even once game-ified the laser itself, turning it into a physical version of Space Invaders. Be sure to check it out!

 

Sort Out Chemical Storage For Your Shop

There is one constant in the world of hardware hacker’s workshops, be they a private workshop in your garage or a public hackspace, and it goes something like this:

Everybody’s a safety expert in whatever it is they are working with, right up until the accident.

In other words, it is very tempting to harbour a cavalier attitude to something that either you are familiar with or the hazards of which you do not understand, and this breeds an environment in which mishaps become a distinct possibility.

As hardware people, we are familiar with basic tool safety or electrical safety. The chances are that we’ve had it drummed into us at some time in our growing up, by a lab supervisor, a workshop teacher, or a parent. That you as readers and I as writer have survived this long is testament enough to the success of that education. But what about those areas in which we may not have received such an education, those things which we either encounter rarely or seem harmless enough that their safety needn’t be our concern? Chemicals, for example: everything from glue through solvents and soldering consumables to PCB chemicals and even paint. It all seems safe enough, what could possibly go wrong? The answer to that question is probably something most of us would prefer never to find out, so it’s worth looking in to how a well-run workshop can manage its chemicals in as safe a manner as possible.

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