Rushing The Design And Construction Of LED Centerpieces

August 11, 2017 by Donald Papp 7 Comments

‘Dragon Flame’ RGB LED table centerpieces, by [Alex Lao]

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.

For an added perspective on needing to get production right the first time on a much larger scale, be sure to check out getting an installation made up of 25,000 PCBs right the first time.

Dead Bug Soldered LED Ring Of Awesome

August 2, 2017 by Jack Laidlaw 54 Comments

Sometimes the simplest things in life are the most beautiful. [The Tweaker] has soldered an LED circle on the top of an ATmega328P chip, and it looks great.

Using nothing more than some solder, wire, 20 x Pico 0402 (1mm x 0.5mm) blue LEDs and an ATmega328P (7mm x 7mm), [The Tweaker] managed to cram 20 LEDs into a circle on the top of the chip soldered in dead bug style. The chip is running some Arduino code and is operating on the 8 MHz internal ~~crystal~~ oscillator, so that manages to keep the part count low. The soldering is done in a spiral so the LED terminals are hooked up to the right pins, but it seems to add to the aesthetics of the project and looks like it would take a really steady hand. Once you connect a power source it displays chasing lights as well as other light patterns.

There may not be much to this project but it does look great.

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Edge-lit Pendants Show Two Layers Are Better Than One

July 28, 2017 by Donald Papp 7 Comments

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.

No-Solder Breadboarding For SMD LEDs

July 12, 2017 by Lewin Day 19 Comments

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.

Graduation Cap Shows Us What It’s Got!

June 30, 2017 by James Hobson 15 Comments

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!

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A Table From Beyond Infinity

June 26, 2017 by James Hobson 10 Comments

Infinity mirrors are some far-out table mods and make a great centerpiece. Instructables user [bongoboy23] took a couple steps beyond infinity when designing this incredible table tailor-made for our modern age.

Poplar and pine wood make up the framing, and red oak — stained and engraved — make for a chic exterior. Programmed with Arduino and run on a Teensy 3.1, the tabletop has 960 LEDs in forty sections. There are, four USB ports hidden behind sliding panels, as well as a two-port AC outlet and an inductive charging pad and circuit. A hidden Adafruit TFT touchscreen display allows the user to control the table’s functions. Control is limited to changing lighting functions, but Pac-Man, Snake, and text features are still to come!

Weighing in at $850, it’s not a cheap build, but it looks amazing.

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Helix Display Brings Snake Into Three Dimensions

June 7, 2017 by James Hobson 7 Comments

Any time anyone finds a cool way to display in 3D — is there an uncool way? — we’re on board. Instructables user [Gelstronic]’s method involves an array of spinning props to play the game Snake in 3D.

The helix display consists of twelve props, precisely spaced and angled using 3D-printed parts, each with twelve individually addressable LEDs. Four control groups of 36 LEDs are controlled by the P8XBlade2 propeller microcontroller, and the resultant 17280 voxels per rotation are plenty to produce an identifiable image.

In order to power the LEDs, [Gelstronic] used wireless charging coils normally used for cell phones, transferring 10 W of power to the helix array. A brushless motor keeps things spinning, while an Arduino controls speed and position via an encoder. All the links to the code used are found on the project page, but we have the video of the display in action is after the break.

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