The Band’s Name In Lights, RGB LEDs To Be Exact.

November 8, 2012 by Brian Benchoff 18 Comments

A few of [michu]’s friends formed a band named Kalikut Now and needed an awesome stage show. The band made a few 80cm-high letters of their band name, cut a few pieces of acrylic, and wired them up with a few LED modules. The work of connecting these letters to a computer and programming them fell on [michu], and we’ve got to say he did a pretty good job.

You may remember [michu] from his StripInvaders and PixelInvaders projects, basically a few RGB LED modules that can communicate with an Arduino over an SPI interface. With these huge letters, [michu] ran into a problem: he had 11 meters of cabling between the clock and data lines, far beyond the maximum recommended length for any datasheet.

[michu] looked around the Internet for common problems with SPI interfaces and found a lot of good advice from a lot of very smart people. The issue with the SPI bus was eventually solved by correctly wiring the grounds of his LED modules, building a few dead-simple SPI buffers, and reducing the clock speed of the SPI bus.

After countless hours, the band’s name is in lights, and RGB LEDs to boot. Everything can be controlled with Abelton Live, and looks absolutely fantastic as seen in the video after the break.

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Nyan Cat Built Into The Wall Of A House

November 7, 2012 by Mike Szczys 13 Comments

You’re going to need your best negotiating skills if you want to convince your significant other to let you add your own Nyan Cat to the kids’ room. This goes a bit deeper than just mounting something on the wall. The LEDs which light up this Nyan Cat installation are actually in the wallboard itself.

Luckily, this is actually a ‘playground for grown-up kids’. [Schinken] and his fellow hackerspace members built it at their location in Bamberg, Germany. It started as a Nyan Cat scarf, which was easy enough to hang on the wall. To make it sparkle they added sixteen LEDs. But you won’t see the wires from either side. A hole was drilled at the location of each diode, with a trench chiseled between them. This makes room for the wires, and was covered with spackle before painting. It turned out to be a pretty simple way to add a focal point to the room, and it certainly has the appropriate level of geekiness for a hackerspace.

Do Not Look Into 12 Watt UV Lamp With Remaining Eye

November 7, 2012 by Brian Benchoff 33 Comments

We’ve seen a couple of UV lamp builds for exposing photosensitive PCBs and erasing EPROMs, but [John] over at pcboard.ca decided if it’s worth doing, it’s worth overdoing. They designed a UV exposure board using twelve 1 Watt UV LEDs, an impressive amount ultraviolet light that you probably shouldn’t look at for too long.

We’ve seen UV exposure boxes before, usually made with a bunch of 5mm UV LEDs soldered to a piece of protoboard. These projects do their job, but the exposure time is on the order of minutes. The PCboard.ca UV lamp can expose a PCB in just 20 seconds.

The build began with four pieces of aluminum bar, 1 inch wide and 1/8″ thick. The 12 star LEDs were glued down to this bar with thermal adhesive and serve their purpose as a rather large heat sink.

[John] performed a little test to determine how long it would take this monstrous UV source to expose a PCB. By copying a PCB mask four times and placing it over an unexposed board, [John] made a PCB with exposure times of 60, 45, 30, and 15 seconds. After developing and etching, all but the 15-second exposure was fully etched, an amazing result that will probably lead to some very, very rapid prototyping.

All the more impressive is the fact that only four 1-watt LED drivers were used for this build. That’s right, this UV lamp is actually operating at about a quarter of its maximum rating, or about 285mA per LED. We’d hate to see this thing operate at full power, protective eyewear or not.

Beginner Project: Color Sensing With RGB LEDs And A Photocell

November 5, 2012 by Caleb Kraft 16 Comments

I’ve seen the concept art for “real world eyedroppers” several times. I haven’t noticed any of the products come to market though. It isn’t the technology stoping them, color sampling can be done a million ways. I picked one of the easiest ways and tossed something together pretty quickly.

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LED Fun And Light Painting With The PyMCU

November 5, 2012 by Jeremy Cook 2 Comments

Recently [Richard] at [pyMCU] was nice enough to send me one of their units to try out. As featured here before, this little board allows you to control physical things using your computer and the Python programming language. After evaluating it and making a LED blink, there were a couple other LED projects I wanted to try.

The first idea was to make a LED chaser. This was quite simple, using a little code and plugging in a few LEDs. From this, since you can make the LEDs chase each other, then in the right sequence it should be able to be used to display images using long-exposure photography. Be sure to check out the video after the break of this 10 LED chaser/light bar being assembled.

The results of this LED light bar experiment were really cool, writing some simple text and image with 10 LEDs. Considering the low component count, this is one of the simplest light bar builds that we’ve seen. Programming was simple as well, since the computer using Python does all the processing of the drawing as well as physically turning the LEDs on and off. Of course this setup isn’t without its limitations, having to be connected to a computer being the most obvious. Continue reading “LED Fun And Light Painting With The PyMCU” →

Thinking Cap Is Also Party Hat

November 5, 2012 by Eric Evenchick 10 Comments

The Thinking Cap is a piece of wearable signage that lets you display what’s on your mind. The hat uses a Teensy 2.0 connected to a Bluetooth radio to allow the wearer to update the message on the fly, letting the room know what their thinking at that instant.

This hack is based off of LPD8806 controlled LED strips, which are becoming very popular for adding lots of LEDs to anything. There are five strips that need to be controlled over SPI, but the Teensy only has one SPI peripheral.

This lead to the use of multiplexer to allow for controlling each strip individually. The hat uses an interesting and low cost scheme to multiplex five channels using two 744052 dual 4 channel multiplexors and a 7400 inverter.

The Teensy can receive messages using the Bluetooth serial port protocol. The 5 x 7 pixel characters are stored in a framebuffer, and shifted around the hat to create the animation.

The result is a bright message circling around the user’s head, which can be updated with a smartphone over Bluetooth. Check out a video demo of the hat after the break.

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Bluetooth Control For Your DSLR Or Just About Any Other IR Operated Device

October 30, 2012 by Mike Szczys 8 Comments

Just the other day we were reading a Reddit thread asking about how to control a television with a smartphone. The conversation started by talking about adding an IR LED to the phone. Then it was suggested that there should be standalone Bluetooth devices that convert commands to IR, and came around to the ideas that TV’s should ship with native Bluetooth hardware. We couldn’t agree more but we’re also not about to replace our TV just for this option. That’s why we were delighted to find this project waiting on our tip line. It’s a method of controlling a camera shutter from a smartphone using Bluetooth. But the technique will work for any device which uses an infrared remote control.

The video after the break shows two different devices controlling the camera shutter. As you can see in the diagram above, the iPhone is the master controller, connecting to a Bluetooth headset mounted on the camera. That headset was altered to feed the speaker connections into an IR LED pointed at the camera’s receiver. The iPhone plays an encoded audio track matching the IR remote command, resulting in the properly formatted message flashing on the LED. The watch doesn’t have the ability to playback audio, but it can send a message to the phone, which then plays the proper audio track through the headset.

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