Status Light Tells You The Code Is Borked Again

December 12, 2013 by Adam Fabio 5 Comments

status light

[Arthur] is teaching himself product development. Rather than create a few mock-up products, he’s taking the path of designing real devices he can use. His current device is a status light for automated software tests. We’ve seen test and GitHub status lights before, however this is the first one to integrate with an outside web service. The status light’s state is based upon output from CodeShip, an online continuous deployment test engine.

The electronic design is simple. An Electric Imp retrieves test status data from CodeShip. The Imp then sends the status data over two GPIO lines to an AdaFruit Trinket. The Trinket controls a NeoPixel ring. A green ring indicates all tests are passing. Purple means tests are in progress. A spinning red ring (of death) means one or more tests have failed. Power is supplied via a mini USB connector.

[Arthur] spent quite a bit of time on the mechanical design of the status light as well. All the parts are 3D printed. This allowed him to quickly go through several revisions of each part. We like the use of white PLA for a frosted effect on the top section of the light, as it diffuses the eye piercing glow from all those RGB LEDs. As a finishing touch, [Arthur] created a fake product page for his light. He doesn’t have any plans to sell it, but we hope he drops the source and STL files so we can create one of our own.

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Finally, An Animated GIF Light Painter

December 12, 2013 by Brian Benchoff 6 Comments

led_strips_dragon-flap

Light painting, or taking a picture of a moving RGB LED strip with a very long exposure, is the application du jour of Arduinos, photography, and bright, glowey, colorful things. Hackaday alumnus [Phil Burgess] has come up with the best tutorial for light painting we’ve seen. It’s such a good setup, it can be used to create animated .gifs using multiple camera exposures.

The build uses an Arduino Uno, SD card shield, and Adafruit’s new NeoPixel strip with 144 RGB LEDs per meter. Despite a potentially huge mess of wires for this project, [Phil] kept everything very, very neat. He’s using an Altoids case for the ‘duino, an 8 AA-cell battery holder and 3A UBEC for the power, and a wooden frame made out of pine trim.

Part of the art of light painting involves a lot of luck, exponentially so if you’re trying to make a light painted animated .gif. To solve this problem, [Phil] came up with a very clever solution: using a rotary encoder attached to a bicycle. With the rotary encoder pressed up against the wheel of a bike, [Phil] can get a very precise measurement of where the light strip is along one dimension, to ensure the right pixels are lit up at the right time and in the right place.

It’s a wonderful build, and if Santa brings you some gift certificates to your favorite electronics retailer, we couldn’t think of a better way to bring animated .gifs into the real world.

LED Concert Dress

December 7, 2013 by James Hobson 13 Comments

[Geri] has an awesome brother. He made this amazing LED dress for her to wear at the [Taylor Swift] concert last weekend!

As you may or may not know, she encourages her fans to bring “glowy” things to wave around at her concerts. A quick check of the exhibition arena’s conditions of entry, and it seemed like LEDs would be allowed, so [Patrick] got to work.

He’s using a set of waterproof red LED strips and a cheap controller ordered from China. They needed a rather beefy battery pack so [Patrick] threw together a switchmode buck converter to drop a 19.8V 4.5A/h battery pack to a constant 12V for the LED controller. Not wanting to mess up the red cocktail dress, their mom sewed the strips into place. The dress is super bright and looks great — it draws about 25W, so the battery pack should last for the entire duration of the concert.

Unfortunately about a week before the concert they discovered Vector Arena is not allowing LED lights into the concert, which as you can imagine, was quite heartbreaking.

Thankfully, someone reached out to the organizers and they made an exception for them! [Geri] even ended up on the front page of their local newspaper! Stick around after the break to see a video of the dress in action!

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Tiny 3x3x3 SMD LED Cube

December 4, 2013 by James Hobson 12 Comments

led cube

LED cubes are cool, but they’re usually pretty big and clunky. [One49th] set out to make one of the smallest LED cubes we’ve seen yet, and he’s shared how he did it in his Instructable!

His first LED cube was the traditional kind, and it turned out pretty nice. But he wanted to go smaller — what about using SMD’s? What he did next was no simple feat — in fact, we’d be willing to call him an artist with a soldering iron. The array is just over one centimeter across.

Using a combination of vices and pliers he soldering each SMD onto his structure one by one. Each LED anode is tied together on each horizontal layer. Each cathode is tied together on each vertical column. This allows the TinyDuino to control any one LED by knowing which of the 9 columns and 3 layers the LED is on. Send a high signal to chosen layer, and a low signal to the column to light the LED. Doing this quickly allows you to create the illusion of different LEDs being on at the same time. Take a look through his image gallery to see just how tight the soldering quarters were, it’s definitely not something we’re planning on doing anytime soon!

Looking for a bigger cube? Check out this gorgeous 7x7x7 one that is capable of 142 frames per second!

Fabricate Your Own 7-Segment Displays

December 3, 2013 by Mike Szczys 10 Comments

We see more and more projects that use custom molds and casting materials. The latest is this custom seven segment display which [Ray74] put together. The idea of making your own LED displays couldn’t be much easier than this — everything but the LEDs and wire is available at the craft store.

He started by making models of each segment out of pink erasers. The lower left image of the vignette above shows the eraser segments super glued to some poster board. The decimal is a pencil eraser, with a fence of wood to contain the molding material. Amazing Mold Putty was mixed and pressed into place resulting in the mold shown in the upper right.

From there, [Ray] cast the clear epoxy three times. Once dried the clear pieces were sanded, which will shape them up physically but also serves to diffuse the light. They were then placed inside of another mold form and an epoxy pour — this time doped with black enamel paint — finishes the 7-segment module. The final step is to glue the LEDs on the back side and wire them up.

This definitely trumps the build which Hackaday Alum [Kevin Dady] pulled off using hot glue sticks as light pipes.

Advice About Over-Driving LEDs

December 3, 2013 by Mike Szczys 64 Comments

advice-about-overdriving-leds

We usually stay within the recommended Amperage with LEDs, but multiplexed displays provide an interesting opportunity to push them outside of that range. Because multiplexing scans a set of LEDs, they are not on all of the time. If your multiplexing setup allows you to remain within a certain time frame and duty cycle they can be driven past the constant current specifications. [Bryanduxbury] decided to take a look at the best way to overdrive LEDs.

The example that he gives is that his 30 mA constant current rated parts can accept up to 185 mA but only for 0.1ms with a duty cycle of 10%. If you know how to apply these figures you can get them to shine much brighter. This becomes especially useful when your multiplexed display already has the light off for the majority of the time because the resulting average luminosity will be much higher. His side-by-side test is shown above. With a current limited LED on the left of each color group, a multiplexed LED driven at normal voltage in the middle, and multiplexing with overdrive on the right.

The biggest drawback that [Bryan] mentions is that if your firmware hangs for more than the spec’ed time you’ll definitely fry these diodes.

Energy Harvesting Peltier Ring

December 2, 2013 by James Hobson 51 Comments

[Sean] is by no means an electrical engineer, but when he discovered the magic of Peltier plates he knew he had to make a project with them. This is his Energy Harvesting Peltier Ring.

The effect he is harnessing is called the SeeBeck Effect — the process of generating electricity through temperature differentials. He has shown how peltier plates work to many people, and, as you can guess, most people think they are amazing (free energy wow!). Unfortunately, most peltier plates are rather large and bulky, so [Sean] decided he wanted to try to design something small enough that could fit on a ring. Just a proof of concept, to light a tiny SMD LED.

The tiny Peltier plate he found generates about 0.3V with a temperature differential of about 20C — not bad, but it won’t light up any standard LEDs at that voltage! He started looking into voltage steppers and discovered Linear Technology’s 3108 Ultralow Voltage Step-up converter and Power Manager — a surface mount chip capable of scaling 0.3V to 5V. The only problem? [Sean’s] never done surface mount soldering.

His first circuit was built on a prototyping board, and after it worked successfully, he designed a PCB using Fritzing. Another success! Prototyping complete, it was now time to try to downsize the PCB even more to fit on a ring. Realizing there was no way he was going to fit it on a single ring, he decided to make a double ring out of CNC machined aluminum. He made use of his school’s CNC shop and the ring came out great. It works too! The room has to be fairly cool for the LED to light, but [Sean] definitely proved his concept. Now to make it even smaller!