Make Your Own LED Lightbulb!

November 3, 2013 by James Hobson 43 Comments

LED lightbulb

Do you like saving electricity? Who doesn’t!

Do you have a lot of LED light strips lying around, destined for a project that you never quite got around to? We’re guilty!

Do you have an old DC power adapter? Of course you do.

Do you love soldering? Duh.

Do you have a dead fluorescent light bulb sitting around? Maybe…

If so, here’s a quick and silly guide to making your very own LED light bulb! The result is a bit ghetto we admit, but quite functional. Perhaps it could be improved by adding a glass Christmas bobble to make it look a bit more like a regular light bulb. And if you’re ambitious enough you could throw a microprocessor in there and add wireless control to it as well … but let’s be honest, smart LED light bulbs are getting quite affordable these days. But hey, you’ve got to do something for entertainment!

LED Bulb Reviews, Evaluations And Teardowns

November 1, 2013 by Todd Harrison 25 Comments

[ElectronUpdate] has posted many great reviews of commercial LED bulbs that one can purchase to replace standard E26 incandescent light bulbs. In his reviews he evaluates the light emitting performance and does a thorough and detailed teardown, evaluating and understanding the circuit technologies used. For the light emission evaluation he uses a light meter and some homemade graph paper to plot the lumens at different angles. Flicker is easily evaluated using a solar panel from a discarded solar path light connected to his oscilloscope. Any flicker will show up quite nicely and can be measured. Of course a kill-a-watt meter makes an appearance in most reviews to read watts and power factor.

Recently [ElectronUpdate] wanted to understand the meaning of CRI which is advertised on many of these commercial LED packages. CRI stands for color rendering index and deals with how colors appear when compared to a natural light source. After doing some researching he found that a CRI over 80 is probably good for LED lighting. The next dilemma was how to measure CRI without expensive scientific equipment. He found a website that we have featured before with free software and instructions on how to build a spectrometer. The web instructions include building a meter box from paper but he found it was much more reliable if built out of wood. We’ll let you follow [ElectronUpdate’s] recommended build if you like, but you’ll need a few items which he does detail.

After a short calibration procedure the final rig will measure power spectral line densities of your light source. [ElectronUpdate] is promising more details on how the colorful measurement data can be related to CRI ratings, but you can get a jump on the details at Full Spectrum Solutions. We also recommend you browse through all of [ElectronUpdate’s] LED bulb reviews on YouTube if the progressing performance and innards of LED bulbs fascinates you as much as it does us.

Hackaday Logo Projector From A Single LED

October 31, 2013 by Mike Szczys 11 Comments

Here’s another Trinket Contest entry that was interesting enough for its own feature. [Adam] made his own Hackaday version of the Bat signal. It’s not nearly as big, but the concept is the same. Using this single modified LED he’s able to project a 12″ image that seems quite well-defined (more pictures below).

The LED is one he pulled from an old flashlight. After sanding the dome flat he made a jig which positioned it inside of his laser cutter. From there he etched the 0.1″ logo and filled the negative space with some ink. The remaining surface was polished to help the light shine through, then positioned in front of a jeweler’s loupe to magnify the image.

There’s just a couple of hours left before the Trinket Contest draws to a close. Get your entry in for a chance to win!

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Light Controller Goes Overboard For Halloween

October 31, 2013 by Mike Szczys 15 Comments

floodbrain-halloween-light-controller

Yep, we said it. This Halloween decoration goes way overboard… and we love it! Not only does [Shelby Merrick] put on an incredible sound and light show for the neighborhood, but he keeps us happy by posting all the details for the lighting controller he designed. He calls the creation FloodBrain as it’s switching a set of flood lights to achieve the effects seen above. But for the full experience you’ll want to watch the demo videos below as well.

He needed a way to switch twelve RGB flood lights which pull 10 Watts. His controller was designed to communicate with them via RS485, with an AVR Xmega8E5 controlling the system. We like it that he included some images of the manufacturing process, using a stencil for solder paste before placing components for reflow.

The floodlights themselves are also an interesting hack. To get what he wanted at the best price he picked up 10W white LED flood lights for about eight bucks a piece, then swapped out the LED itself for an RGB version (same wattage) using the same heat sink and case.

More often that not we see this type of system controlling Christmas lights. [Shelby] mentions that he did get help from Christmas light controller forum We also think he should have no problem repurposing the controller for that type of application.

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LED Magic Staff Just In Time For Halloween!

October 29, 2013 by James Hobson 10 Comments

[Dave]’s been working pretty hard on his Arduino driven, LED-lit, magical staff for the past few months, and now it’s finally coming together.

He’s using 6 LED strips that contain 55 LEDs each — at full brightness the staff can suck up an impressive 20A @ 5V! To power it, he’s equipped the staff with 8 NiMH C size batteries (5000mAh @ 1.5V). This works out to about 15-20 minutes of runtime at full power (255, 255, 255, LED values) — to counter this he usually runs a sparkly LED algorithm that lasts much longer. Besides, at full power it’s really quite blinding.

The staff is controlled by an Arduino Uno and currently only has two different modes: random and full brightness. Not to worry though, he’s planning on adding a sound sensor to turn it into an equalizer, a shock sensor to give it a cool ripple effect while walking, and maybe a few other interesting patterns!

Stick around after the break to see the first test video!

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An Impressively Large LED Matrix

October 26, 2013 by Brian Benchoff 10 Comments

One of the more impressive projects a home-bound tinkerer can pull off is some sort of display. Not only does the final project result in a lot of blinky, glowey things, but driving hundreds of LEDs is an achievement in itself. [Fabien] decided he wanted to build his own LED display and ended up with something great (French, Google translation).

Instead of going off the deep end and making his own boards for this giant LED display, [Fabien] found a very cheap 16×32 LED display board on DealExtreme. Once these kits were pieced together, [Fabian] mounted them in a wooden frame and started connecting the displays together.

The original plan was to drive these with an Arduino, but with so many pixels he quickly ran out of RAM. Replacing the Arduino with a larger ATMega1284p, [Fabian] found the RAM he needed and started work on some interesting visualizations.

Of course, Conway’s Game of Life made a showing in the final build, but [Fabian] also managed to whip up a spectrograph using FFT. It’s a very nicely put together display that makes us want to buy a few of these displays ourselves.

Old Fax Machine Shows Signs Of Life

October 24, 2013 by Adam Fabio 5 Comments

fax1

[Dmitry] is a Moscow based artist. He’s also a an avid circuit bender and hardware hacker. His latest project is entitled “signes de vie” or signs of life. [Dmitry] started with an Arduino and an old thermal fax machine. He removed the thermal print head and replaced it with a row of 10 LEDs. These old fax machines would use rolls of paper, cutting each sheet of as it was printed. [Dmitry] kept the roll system, but treated his paper with fluorescent dye. As the paper passes under the LEDs, it pauses for a moment and the LEDs are flashed. This causes a ghostly glow to remain on the paper for several minutes as the next rows are printed.

While [Dmitry] could have made this the world’s biggest tweet printer, he chose to go a more mathematical route. Each printed row of dots represents a generation of one-dimensional cellular automata. Cellular automation is a mathematical model of generations of cells. All cells exist on a grid, and can be alive or dead. The number of neighboring live cells determines if any given cell will live on to the next generation. One common implementation of cellular automation is Conway’s Game of Life. In [Dmitry’s] implementation, a bank of switches select which of the 256 common cellular automata rules controls the colony. A second bank selects how long each generation lasts – from 1 to 18 seconds.

We really like how the paper becomes a printed, yet temporary history of the colony. [Dmitry] doesn’t say if he’s using a single long strip of paper, or if he created a loop. We’re hoping for the latter. Finally a useful implementation of the old black fax loop prank.

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