Sometimes the most important thing is getting something done.
[Alex Lao] was recently in such a situation. His sister was getting married and he designed, built, and delivered twenty RGB LED table centerpieces in a rush. There were no prototypes made, and when the parts arrived all twenty were built all at once over a single weekend. These table centerpieces are illuminated by RGB LEDs and battery-powered, but have an option to be powered by a wall adapter.
[Alex] helpfully shared some tips on reducing the production risks and helping ensure results in such a limited time frame. His advice boils down to this: reduce the unknowns. For Alex this meant re-using code and components from a previous project — even if they were not optimal — so that known-good schematic and footprint libraries could be used for the design.
From one perspective, the PIC32 microcontroller inside each lamp is overkill for an LED centerpiece. From another perspective, it was in fact the perfect part to use because it was the fastest way for [Alex] to get the devices working with no surprises.
The invention of the LED is one of the most important discoveries of our times. They are everywhere, from our flashlights to household lighting and television sets. We don’t need to tell you that a project with more blinkies is better than a project with fewer blinkies. But an LED is not simply an LED; the sheer variety of LEDs is amazing, and so in this write-up, we’ll take a closer look at how to choose the right LED for your next masterpiece. Continue reading “Know Thy LED”→
Not all projects are made equal. Some are designed to solve a problem while others are just for fun. Entering the ranks of the most useless machines is a project by [Vladimir Mariano] who created the 3D Printed Dancing Springs. It is a step up from 3D printing a custom slinky and will make a fine edition to any maker bench.
The project uses 3D printed coils made of transparent material that is mounted atop geared platforms and attached to a fixed frame. The gears are driven by a servo motor. The motor rotates the gears and the result is a distortion in the spring. This distortion is what the dancing is all about. To add to the effect, [Vladimir Mariano] uses RGB LEDs controlled by an ATmega32u4.
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.
Breadboarding is a great way to get started with electronics, and with the wide availability of those little wire jumpers, it’s never been easier – until you hit roadblocks due to poor connections and parasitic capacitance futzing with your signals. However, in today’s current climate, the latest and greatest modules are too often available only in SMD packages, and while breakout boards can help, it’s probably overcomplicating things a bit when it comes to SMD LEDs. It’s all good, though – [Simon Merrett] has a workaround, as part of his Yapolamp project.
[Simon] first took a flat strip of steel, and placed two neodymium magnets on top. The assembly was then wrapped in electrical tape for insulation, and two contacts were created with copper tape. The LEDs were then placed across the two contacts and wires were attached to join them to the breadboard. The 5630 LEDs [Simon] must contain some sort of ferrous material, because they were attracted to the magnets and sat neatly in place.
It’s a neat hack that would be particularly useful if you needed to quickly swap out LEDs, and saves them from damage by soldering. Meanwhile, check out this SMD LED matrix from 2009.
A high school graduation ceremony is well due the pomp and circumstance for making it through one of life’s many milestones. To commemorate the event with their own flair, redditor [PM_(cough)_FOR_KITTENS] hid a 32 x 32 GIF-playing LED matrix in their graduation cap!
The board is controlled by a Teensy hosting a SmartMatrix shield. With the shield’s assistance, the matrix enables scrolling text and GIFs to play across the LEDs, as well as an SD card slot to load up your favourites. Currently, it’s set to a 50-50 chance of playing a gif — one of sixty — or one of the twenty scrolling text lines loaded onto the SD card. [PM_(ahem)_FOR_KITTENS] co-opted his friend’s expertise to write the code — available here — while he designed the circuit and handled the assembly.
Carefully unwrapping his cap, [PM_(yep)_FOR_KITTENS] reinforced it with thinner and stronger cardboard, cutting slots into it, allowing the boards and wires to — barely — fit inside. A hole in the side of the cap is enough for a barely noticeable USB cable to run down his neck to a 2000 mAh battery which can power the cap for over five hours at 5V and 2A. Check out a demo video after the break!
By now it might seem like there’s no new way to build a binary clock. It’s one of the first projects many build to try out their first soldering irons, so it’s a well-traveled path. Every now and then, however, there’s a binary clock that takes a different approach, much like [Stephen]’s latest project which he calls the byte clock.
The clock works by dividing the 24-hour day into half and using an LED to represent this division, which coincidentally works out to representing AM or PM. The day is divided in half over and over again, with each division getting its own LED. In order to use this method to get one-second resolution it would need 16 LEDs, but since that much resolution isn’t too important for a general-use clock, [Stephen] reduced this to eight.
Additionally, since we’re in the Internet age, the clock has built-in WiFi courtesy of a small version of Python called WiPy which runs on its own microcontroller. A real-time clock rounds out the build and makes sure the clock is as accurate as possible. Of course an RTC might not have the accuracy as some other clocks, but for this application it certainly gets the job done.