The Butt Lamp: Light From Where The Sun Don’t Shine

January 23, 2014 by Adam Fabio 28 Comments

[Trent] is one of those guys who can make things happen. A friend of his gifted him a mannequin derriere simply because he knew [Trent] would do something fun with it. “Something fun” turned out to be sound reactive LED butt. At first blush, this sounds like just another light organ. This butt has a few tricks up its …. sleeve which warrant a closer look. The light comes from some off the shelf 5050 style RGB LED strip. The controller is [Trent’s] own design. He started with the ever popular MSGEQ7 7 Band Graphic Equalizer Display Filter, a chip we’ve seen before. The MSGEQ7 performs all the band filtering and outputs 7 analog levels corresponding to the amplitude of the input signal in that band. The outputs are fed into an ATTiny84, which drives the RGB strip through transistors.

The ATTiny84 isn’t just running a PWM loop. At startup, it takes 10 samples from each frequency band. The 10 samples are then averaged, and used to create a noise filter. The noise filter helps to remove any ambient sound or distortions created by the microphone. Each band is then averaged and peak detected. The difference between the peak and the noise is the dynamic range for that band. The ATTiny84 remaps each analog sample to be an 8 bit value fitting within that dynamic range. The last step is to translate the remapped signal values through a gamma lookup table. The gamma table was created to make the bright and dark colors stand out even more. [Trent] says the net result is that snare and kick drum sounds really pop compared to the rest of the music.

Without making this lamp the butt of too many jokes, we’d like to say we love what [Trent] has done. It’s definitely the last word in sound reactive lamps. Click through to see [Trent’s] PCB, and the Butt Lamp in action.

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A Light-Up Dress For A New Year’s Dance Party

January 15, 2014 by Marsh 5 Comments

wearableLedress

Don’t let the above picture’s lack of blinking colors fool you, the light-up dress [Sam] fashioned for his girlfriend is rather eye-catching; we’d just rather talk about it than edit the gifs he’s provided. [Sam’s] been a busy guy. His last project was a Raspberry Pi digital photo frame, which we featured just over a week ago, but wearable hacks allow him to combine his favored hobbies of sewing and electronics.

If you’re looking to get started with wearable electronics, then this project provides a great entry point. The bulk of the build is what you’d expect: some individually-addressable RGB LEDs, the ever-popular FLORA board from Adafruit, and a simple battery holder. [Sam] decided to only use around 40 of the LEDs, but the strips come 60 to a meter, so he simply tucked the extra away inside the dress and set his desired limits in the software, which will allow him to preserve the entire strip for future projects. If you’ve ever attempted a wearable hack, you’re probably familiar with how delicate the connections can be and how easily the slightest bend in the wiring can leave you stranded. Most opt for a conductive thread solution, but [Sam] tried something different and used 30 AWG wire, which was thin enough to be sewn into the fabric. As an added bonus, the 30 AWG wire is insulated, which permits him to run the wires close to (or perhaps over) each other while avoiding shorts. [Sam’s] guide is detailed and approachable, so head over to his project page if you think you’ve caught wearables fever, and check out his GitHub for the source code.

504 Segment Clock

January 14, 2014 by Kevin Darrah 34 Comments

Trying to reinvent the clock has been done over and over again, but it’s always fun to see how over-engineered and complex these designs can get. [Bertho’s] last working clock in his house was the built-in clock on the VCR, so he decided it was finally time to build his own 504 Segment clock.

Yep, that’s right, 504 Segments! This clock uses 72 7-Segment displays to tell time. The video after the break shows the clock in action, but time is read by looking at each ring of displays: outer=seconds, middle=minutes, and inner=hour. [Bertho] could’ve just stopped there, but he decided to load the display up with sensors, so hand-waiving can change modes, and brightness can be regulated based on ambient light conditions. And since he has individual control over each segment, he has implemented some pretty cool mind-melting animations. Oh, and did we mention that the display synchronizes with an NTP server?

The display is divided into 4 quadrants, each containing 18 7-Segment displays. The control architecture is interesting because each quadrant is controlled by its own PIC microcontroller, which handles the continuous multiplexing and modulation of the 18 7-Segment displays. A main control board contains another (more powerful) PIC to update the 4 quadrants via a serial bus. This board also handles the Ethernet connection, sensor interface, and local RTC(real time clock). This isn’t the first time we’ve seen [Bertho’s] amazing work, so make sure you check out his useless machine and executive decision maker.

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A Simple LED Flashlight Composed Of A Relay And A Magnet

January 13, 2014 by Mathieu Stephan 22 Comments

In our tips line we sometimes receive hacks that are amazing just because of their ingenuity. This relay-powered flashlight is definitely one of them. It has been named RattleGen by its creator [Berto], who apparently often makes simple hacks used in his everyday life (have a look at his YouTube channel).

To understand this hack, you first need to know (in case you didn’t already) that a magnet moving near a conductor (here a coil) induces a voltage at its terminals. This is called electromagnetic induction. In the picture you see above, you may distinguish a disassembled relay with a magnet located on the lever’s end. As a ferromagnetic metal is already placed inside the coil, the lever is by default ‘stuck’ in this position. By continuously pressing the latter on its other end, important voltage spikes are created at the coils terminals. [Berto] therefore used a bridge rectifier to transform the AC into DC, and a 1000uF capacitor to smooth the power sent to his super bright LED. A video of the system in action is embedded after the break.

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Saving $20,000 USD With A Single LED

January 12, 2014 by Adam Fabio 81 Comments

carrier

[N8Mcnasty] is a HVAC tech who works on some big machines. One of his charges is a Carrier 19EX Chiller, rated at 1350 tons of cooling. 1 ton of cooling = 12,000 BTU. This particular chiller contained an odd LCD screen. It used a fiber optic bundle and a halogen light for backlight illumination. The system worked fine for over a decade. Now though, the halogen bulb has begun melting the glue on the fiber bundle, causing a dim display. The display in question shows some very important operating parameters, such as oil temperature, current draw, and process temperatures. Since they couldn’t easily see the display, the machine’s operators weren’t running the machine, placing stress on the other chillers in the building’s physical plant. [N8Mcnasty] tried repairing the bundle, however the glue kept melting.

A replacement display was no longer available, meaning that the entire chiller control system would have to be upgraded to a newer system. The new control system uses different sensors than the old one. This is where things start getting expensive. Replacing the sensors would also require draining the 15-20 gallons of oil, 4500 lbs of R134a refrigerant, and bringing the whole system down for almost two weeks, a $20,000 job. Rather than go this route, [N8Mcnasty] found an alternative. LED’s have come a long way since 1996, when the chiller was built. He simply replaced the halogen bulb with an LED and appropriate resistor. [N8Mcnasty] was even able to reuse the halogen bulb bracket. A bit of heat shrink tube later, and the fix looks like it was a factory option. He’s documented his fix here on reddit.

I Am The Midnight Message Board What Messages At Midnight

January 11, 2014 by Kristina Panos 15 Comments

Photoluminescent stars on your bedroom wall or ceiling are pretty cool, though the stationary shapes can become boring. [Adi] felt this way, too. While doodling with a bright white light on some glow in the dark vinyl, it occurred to him that this could make for an interesting display. He set about making GLO, the midnight message board and RSS display.

[Adi]’s light writer uses 12 UV LEDs on a linear axis powered by a stepper motor to write RSS headlines, Twitter trends, or custom text on his wall. He finds the slow fade of the text very soothing to fall asleep by, and it’s easy to see why. The LED array imprints a section of a character consisting of a 6×5 bit pattern. The 12 LEDs are split into two groups, so it can write two lines at 45-50 characters each. [Adi] designed his own pixel font for this project, and advises that only upper case letter forms be used.

[Adi]’s write-up is quite admirable and comprehensive. In the circuit build section, he advises that the LEDs must be very close to the vinyl for optimum results, but that they should protrude farther than the shift registers so the chips don’t rub the vinyl. Of course you could opt for more intense light sources, like laser. See it in action after the break.

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