[Rick Osgood] wanted to build a color sensor that could be held up to any object to get RGB color values. He originally started with a photoresistor and a few LEDs, but couldn’t get that to work reliably. [Rick] finally completed his color sensor after finding a digital luminosity sensor on Adafruit, ending up with a pretty accurate piece of hardware to judge the color of something.

The idea behind the color sensor is to light up red, green, and blue LEDs and see how much light is reflected back from the object with a luminosity sensor. [Rick] chose an Arduino to do all the heavy lifting for the light sensor and activating the LEDs.

After a few tests [Rick] got his color sensor working, but it’s not up to par with what he had expected. This isn’t really a problem: the LEDs probably don’t have the same brightness and the luminosity sensor doesn’t respond evenly across the entire rainbow. Those things can always be fixed in software, though. It’s a nice project that could serve as part of a prototype for this color picker pen.

The sales team in [Chuck’s] office is a pretty competitive bunch as you might expect, and they decided that they wanted a system which would allow them to challenge one another during their weekly meetings. The competition involves answering questions posed by their manager, but hand raising only works for so long – they needed a definitive way to tell who “buzzed in” to answer a question first.

Since [Chuck] only had a short bit of time and a tiny budget to work on, he opted to find the easiest solution to the problem, which was an Arduino-based game show buzzer system. The game display is built from an Arduino, some LEDs and an Altoids tin, while the buzzer pushbuttons were salvaged from an old radio broadcast console.

Now, when a question is posed, the salesman can buzz in to answer, knowing that only the quickest person’s button click will be registered. When it’s time for another question, the host simply clicks his buzzer to reset the console.

While it’s not quite as fancy as this game buzzer system we featured a while back, [Chuck] says it does the job perfectly and was cheap to boot.

Continue reading to see a short video of the office game buzzer system in action.

LEDs and and cameras always make a fun mixture, and its not all that hard to have quite a bit of fun as well. The Light Painting Stick is similar to other long exposure camera tricks like LightScythe and gets about the same reults. The difference is the Light Painting Stick is self contained meaning you don’t have to drag nearly as much stuff along with you to have fun.

Hardware used is HL1606 controlled RGB led strip commonly found at Adafruit, the brains are a Leaf Labs Maple micro controller board with an SD card and some human interfaces attached, and is powered by a 6 volt lantern battery.

Images are 64*infinity 24 bit BMP files which means there is not much fuss preparing your graphics other than doing a simple rotate. You can select which image is displayed by using a 2 way switch and the LEDs on the stick. Select your images, dial in your speed with the potentiometer, and you’re  ready to hit the fire button for some photo fun.

[Martijn] is showing off his new clock which he calls a Light Spectrum Clock. We like to look of it, using RGB LEDs in five squares that remind us of some of those LED coffee table builds. From left to right this shows the week, day, hour, minute, and second. Simple, right?

We had to smile a little bit when looking through his write up. He chose an Arduino nano as a controller, using a TLC5940 chip to drive the LEDs. But it is the inclusion of a DS1307 real-time clock that we find amusing. It will keep quite accurate time (not quite as well as the DS3232 but still respectable) but the fuzzy display technique makes telling the time accurately an impossibility. But like other color-based clocks, that’s part of the fun. The real reason for using an RTC chip is that they usually include battery-backed operation so that you can shut off the LEDs when you’re not around and the clock will continue to tick.

You can watch the seconds pass by as fading colors in the clip after the break.

For his first big build with an MSP430, [Javon] decided to an RGB LED fader. Having worked with Arduinos in the past, he figured that his MSP430 would have a few PWM channels. After being proved wrong by the data sheet, [Javon] needed to figure out a way to switch a bunch of RGB LEDs with only one PWM channel on his microcontroller.

Because there was only one PWM pin on [Javon]‘s micro, he needed a way to multiplex his output. He ended up using a 74HC4052 mux/demux chip to drive 20 LEDs. The LEDs were mounted onto hard board and the main part of the circuit built on a bit of perfboard. While there’s no total cost for his build, we’re guessing [Javon] didn’t spend much on his project; certainty much less than this explosion of LEDs.

[Javon] put all the build pictures up as a Google+ album and a few video demos up. Check those out after the break (009 Sound System warning, you might want to hit mute).

The headlight enclosures on [Bill Porter's] 2004 Passat had yellowed with age and were not outputting the kind of light they should. He decided to replace them with some aftermarket modules that also incorporated LED strips. When they arrived he was surprised at how easy there were to drop into place. But when testing he was certainly not satisfied with how they worked. The day-driving mode used the HID bulbs at full power, where the factory assembly had dimmed them during the day. He set out to alter the electronics to work as he prefers.

Always the mad scientist, [Bill] started off by making a truth table showing how the lights reacted to the various states of the ignition and headlight switches. What he came up with is an AND gate built from a relay and diode. It allows him to have the LEDs on as the running lights (without the HIDs on at all), and leaves the rest of the functionality unaffected.

[George] just finished his first project: an 8×8 matrix “Board of Many Ping-Pong Balls” with 64 RGB LEDs. He started this project when he was 14 years old and finished the build over this last Christmas break. We won’t make any presumptions about [George]‘s age, but we couldn’t think of a better project to start out on.

For the build, [George] used a Colorduino LED driver shield for his Arduino. This made the wiring simple, but the finished product is where this project really shines. For the base, [George] got a board laser cut at his school and used ping-pong balls to diffuse the LEDs. We’ve seen this many times but with this build there’s a neat way to drill a hole in a ping-pong ball; simply put the drill into reverse. The friction is enough to open the ball up, and the chips of plastic come outside instead of remaining in.

We’re really impressed with [George] and his winter break project. He’s lucky enough to have access to a laser cutter at school, and from a look at his monitor, he’s reading the right websites. You can check out his demo rainbow pattern after the break.

[Asher Glick] wrote in to share a project he has been working on with his friend [Kevin Baker], a 4x4x4 RGB LED cube. The pair are students at Rensselaer Polytechnic Institute and also members of the newly-formed Embedded Hardware Club on campus. As their first collaborative project, they decided to take on the ubiquitous LED cube, trimming down the component count to nothing more than 64 LEDs, a protoboard, some wire, and a single Arduino.

Many cubes we have seen use shift registers or decade counters to account for all the I/O required to drive so many LEDs. Their version of the cube has none of these extra components, solely relying on 16 of the Arduino’s I/O pins for control instead. You might notice something a bit different about the structure of their cube as well. Rather than using a grid of LEDs like we see in most Charlieplexed cubes, they constructed theirs using 16 LED “spires”, tucking the additional wiring underneath the board.

The result looks great, as you can see in the videos below. The cube looks pretty easy to build, and with a cost around $60 it is a reasonably cheap project as well.

Nice job, we look forward to seeing all sorts of fun projects from the Embedded Hardware Club in the future!

Lots of people buy noise makers for New Year’s eve, others opt to sing Auld Lang Syne – then there’s these guys.

The crew at Stone Brewing Company throw an annual bash at their brewery in celebration of New Years, and while [Dino’s] countdown timer is great for intimate settings, they needed something bigger to wow the crowd. A busted half barrel was all the inspiration they needed to build the “Doomsday Keg of Radness”.

[Mike Palmer], the Creative Director at Stone handed the keg off to the maintenance crew for some remodeling, and got ready to fit it with all sorts of lights and other goodies. Holes drilled in the keg were fitted with bright pulsing LEDs, while additional LED light strips were laid out around the perimeter. The bottom was cut out to accommodate a Moonflower LED module, and a 24” monitor was strapped to the side in order to display a countdown timer. An old Macbook jammed inside the keg runs the video display, while the rest of the lighting is remotely controlled with an RF transmitter.

Now mind you this all went down last year, but since the display was such a hit, they will be busting it out again for the 2011 celebration.

Check out the short demo video below to get a look at the Doomsday Keg in action.

With 8 drives working in concert, this “floppy drive array orchestra” takes drive music to a whole new level!  As if that wasn’t enough, [SileNT] decided to use the16x64 LED array that he’s been working on in concert with the drives.

For those that remember, we’ve actually featured [SileNT], AKA [Pawel]‘s, work before, where we were impressed that he was able to play the Imperial March from Star Wars on 2 floppy drives. He’s planning more information about his floppy drive music making in the future and maybe even instructions on building your own personal disk drive orchestra. Apparently [SileNT] has an abundant supply of 3 1/2 inch drives, so maybe even this feat can be topped…

Be sure to check out the video after the break of these 8 drives in action. In the video, more tunes are promised “soon”, so be sure to check back or subscribe to him on Youtube for more sweet melodies.

[Ytai Ben-Tsvi] wrote in to share a little holiday project that he and friend [Al Linke] put together, a dynamic light display that takes its cues from his Android-powered smartphone.

The display fits in a vase that sits in [Ytai’s] family room, and while it wasn’t exactly cheap to build, it sure looks nice. The vase is full of feathery decorative bits which help hide an addressable RGB LED strip. The lights are controlled by an IOIO board which the pair tucked away inside the vase as well.

The IOIO board was also fitted with a USB Bluetooth dongle, allowing it to communicate with just about any handset running a relatively recent flavor of the Android OS. When connected, the phone samples its surroundings with the onboard camera, commanding the vase to mix the colors seen by the phone into its twinkling display.

As you can see in the video below it works pretty well when used with solid, brightly colored objects. While just a fun toy in its current form, [Ytai] and [Al] have more than a few ideas on how to expand its usability.

There’s not much to be gained by living in a discotheque but colored lights are awesome, especially when they’re as well implemented as [michu]‘s StripInvaders.

The StripInvaders project takes a gigantic 5 meter LED strip with WS2801 controllers and turns it into an Ethernet-enabled 24 bit display with the new Arduino Ethernet. While the Ethernet-enabled may seem a little superflous, [michu] implements it quite nicely. The entire 5 meter LED strip can be controlled from a tablet or smartphone.

Apart from a tablet/smartphone interface with OSC, there’s also mDNS support so we’re sure the StripInvaders could make for an interesting LAN party with the appropriate scripts. While the cost of the LED strip itself is fairly high, we’re sure some Hack a Day commenter will come up with a cheaper solution.

The firmware for StripInvaders has been posted on Github, but for a real treat, check out the demo after the break.

One step closer to Robot Santa

Here’s an interesting way to spice up your seasonal headwear. [Mark] took a Santa hat and added a string of multicolored LEDs to the brim. The lights were picked up at a drug store for a dollar. Control is through a simple push button connected to an ATtiny13. Press the button, the lights cycle in a different pattern. Very cool, so check out the video.

A holographic holiday tree

[Auger] posted this very cool light up Christmas tree decoration on Instructables. This tree is made up of three pieces of acrylic. Different designs were laser cut into each piece of plastic – candy canes for the ‘red’ piece, stars and tinsel for the ‘yellow’ piece, and the tree for the ‘green’ piece. LEDs of the respective colors are cemented to the bottom of each bit of plastic. It’s called light piping and is used everywhere. This is the first time we’ve seen three colors, though.

This is what nerds do, and it’s awesome

[Rickard Dahlstrand] was playing around with his phone trying to take deliberately fuzzy pictures of his tree. He noticed the dashes produced from the LED Christmas lights must be produced from PCM dimming. Going through the EXIF data in the picture, he found the exposure time was 1/17th of a second. 1/17 of a second = ~ 58 ms / 5 (cycles on the picture) = ~11 ms per cycle = ~100 Hz frequency on the PCM dimming. Of course this is just about 2 times the line frequency in [Rickard]‘s native Sweden, so we’ll call this confirmed. There’s no blog post for this, but we’ve never seen a clearer example of applied geekery. Simply awesome.

Yeah, we measured [Rickard] on a nerd meter

In the spirit of giving, [Johannes] decided to tell the entire world exactly how nerdy he is. He built a ‘Nerd Alert’ meter out of an old 1950s Japanese multimeter. The old guts of the meter were chucked, and a simple amp made out of a transistor amplifies the current flowing through the user’s fingers. A neat scale ([Johannes] measures somewhere between Amiga Workbench and Space invaders) replaces the old, boring, number-based one. Again, no write-up, but here’s some awesome build pictures.

Finally a use for all those old radio tubes

[AUTUIN] took apart a vacuum tube with a blow torch and a diamond cutting wheel. Surprisingly, he was able to put it back together, but not before making a wonderful Christmas ornament. There are two copper wires inside the envelope that are the leads to a single orange-red LED. The whole thing is powered by a watch battery. We’ll be sure to reference [AUTUIN] next time we have to take apart a glass bulb, because he managed not to burn, cut or blind himself.

Six things in a links post? It’s a Christmas miracle!

[Darryl] sent in a nice tool to select and display all of the hacker/maker merit badges available from Adafruit. Oh, we’re still trying to figure out who to give 10 badges to. We’re giving away skull ‘n wrench badges to the top ten hacks ever featured here. Leave a note in the comments, or tell us who should win.

Holiday wishes

Now put the computer down and go spend some time with your families, or failing that, strangers. Of course there’s an all day Doctor Who marathon, and that thing isn’t going to watch itself…

[LucidMovement] was looking for some crystal-based artwork and just couldn’t seem to find anything that fit the bill, so he decided to build something himself.

The inspiration for his desk lamp came from something we’re all familiar with, a DNA double-helix. To grow the crystals he built a helix-shaped growing substrate out of nichrome and EL wires, submerging them in a warm alum solution. Once he had a nice set of crystals, he mounted it in an acrylic tube, filling the air space with clear silicone to seal off the display. He then mounted the silicone-filled tube on top of a rotating acrylic stand that he had cut for the project. The stand is made from several sheets of acrylic and contains both the gearing for movement as well as RGB LEDs to light the display from the bottom.

The lamp looks great when sitting idle, but when he powers it on it really shines (no pun intended). [LucidMovement] put a ton of work into the lamp, and offers up all sorts of tips, tricks, and considerations for anyone looking to build their own. Be sure to check out his writeup for plenty more details, and stick around to see a short video of the lamp in action.

[Ben Krasnow] wrote in, saying that every so often a news story appears covering a project in which researchers embed a single pixel LED display inside a contact lens. The most recent article he saw featured a contact-wearing rabbit, and not being one to shy away from damaging his own body in the name of science, he decided to try the experiment on himself.

He started out by soldering a tiny 0402 SMD LED to a hand wound coil, laminating the display between a pair of regular contact lenses. After trying to adhere the lenses to one another using water, he opted to tack the edges together with a pair of hot tweezers, making for a more secure but uncomfortable piece of eyewear. The LED is powered by a simple inductive coil he put together, which uses a spark gap transmitter to flash the LED on and off.

If you’re not freaked out by people sticking things in their eyes, be sure to check out the video below to see [Ben’s] augmented contact lens in action. While it might not give him Terminator-like vision, it’s pretty awesome considering he pieced it together in his workshop in his spare time.