Webcam Images Processed And Played Back On LED Display

April 10, 2011 by Mike Szczys 13 Comments

[Mathieu] has bee working to refine the code running on an LED matrix, and added some neat display tricks along the way. He wanted to make the display directly addressable from a computer. The 96×64 bi-color LED display is powered by an Atmel FPSLIC and already used double-buffering. Enabling a PC to write directly to one of the buffers was not too hard, requiring just a bit of optimization to get the timing right. From the look of the video after the break, he nailed it.

The video feed is generated from a webcam stream using Matlab to process each image. Just 50 lines of code captures a frame, sizes it appropriately, converts the result to black and white for edge detection, then finishes the job by compressing image data for transmission to the embedded processor. We’d like to say it’s easier that it sounds but we’re pretty impressed with this work. The display manages about 42 Hz with the current setup.

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Sticky Sweet Animatronic Peep Show

April 7, 2011 by Mike Nathan 14 Comments

peeps_peep_show

With Easter quickly approaching, [Kyle] decided to finally build a project that is as tasty as it is wrong.

Behold, the Animatronic “Peep” show! Using nearly a dozen marshmallow Peeps, he constructed a stage for his “performers” and a seating area for their “clients”. The structure was built mostly from balsa wood and foamboard, featuring a retractable curtain, stage lighting, and music.

Once triggered, the embedded Arduino gets to work animating the stage lights and blaring “Cherry Pie” while the sugar-coated onlookers await their entertainment. The curtain is drawn back and a trio of winged dancers emerge one by one, ready to entertain the crowd. The onlookers even offer up dollar bills to the dancers via a servo-mounted arm.

The project uses a total of 10 servos driven by the Arduino, along with an audio decoder chip to provide the proper ambiance for the marshmallow debauchery. [Kyle] says that he put together about 650 lines of code to get the whole thing running, but there doesn’t seem to be any way to download it at the moment – hopefully we’ll see something posted soon.

It might not be high-brow, but it sure beats blowing up old, stale Peeps in the microwave!

Stick around for a trio of videos demonstrating the Peep show as well as revealing some of the stage’s inner workings.

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Reverse Engineering LED Vodka Bottle Displays

April 6, 2011 by Mike Nathan 10 Comments

wireless_led_marquee

When [Tyler] heard about the LED matrix display that Medea Vodka was building into their bottles, he immediately wanted to get his hands on one. Who could blame him? Someone had finally combined two things we love dearly: booze and LEDs.

He struggled to find a bottle at any of his local stores for the longest time, but was absolutely stoked when he finally came across one of their reps promoting the brand while he was out shopping.

Once he got home, he pulled the display off the bottle and began poking around to see what made it tick. The display is made from a flexible PCB, and attached to the bottle with some clear elastic film. It is powered by two CR2032 batteries and controlled by a PIC16F chip, which pulls stored messages from a small Atmel EEPROM.

Once he figured out how to control the LED matrix, he uploaded his own fonts and added a LINX wireless module to remotely send messages to the board. He mounted it in a wooden frame and now uses it as a simple marquee display.

If you have one of these displays hanging around your house, be sure to swing by his site for schematics of his wireless interface board as well as the code he uses to drive the marquee. You can check out a video of the display in action there as well.

Redeye Printer Interface

April 5, 2011 by Kevin Dady 6 Comments

This handy printer interface started out as a request on our very own forums when forum member [victorf] needed some output via thermal printers. He had scored a number of HP82240B thermal printers intended for use with HP calculators, but of course they used the somewhat arcane HP protocol first drafted in the 1960’s and needed some help.

Fellow forum member [wireb] started to look into it, found out it uses a standard 32KHz carrier signal, and started asking questions about its use. Grabbing a pdf of the manual he was able to find out all the details to what the printer was expecting in the form of communications.

After a few weeks, [wireb] was able to make a convenient, logic level serial to HP-IR adapter based around a PIC16F1824 who’s firmware supports 9600 8N1 or 2400 8N1 speeds, ASCII text, and the printer’s “advanced” graphical modes via escape sequences.

If you have not checked out our forums yet we suggest you do!

Retrofitting LCD Projectors With High-powered LEDs

April 4, 2011 by Mike Nathan 56 Comments

highpower_led

[Devon] recently repaired a handful of Phillips LCD projectors which he was quite excited to use. The only problem is that he didn’t want to mess with replacing the bulbs after every 2000 hours of use at $100 apiece. He was pretty confident that he could find a better way to drive the projectors, so he disassembled them once more and started looking around for bulb replacements.

He figured that a high-powered LED would do the trick, so he ordered a handful of parts and went about his first retrofit. Using his oscilloscope, he found that the control board pulses the high voltage board when the projector is powered on, and continues to pulse a signal until the machine is turned off. At this point, the HV board powers down the bulb.

He created a small circuit using a PIC that is used to interpret the initial pulse from the control board as well as watch for the steady “heartbeat” pulses that occur while the projector is powered on. This board is used to control the driver board for the high-powered LED he purchased.

His bulb replacement works well as far as color fidelity is concerned, but is not nearly as bright as he hoped for. He has plans to source some far brighter LEDs or automobile HID lighting in the very near future, and we look forward to seeing if he can match the brightness of the original bulbs.

Snuggle Up With The Softer Side Of Hacking

March 30, 2011 by Mike Nathan 19 Comments

led_quilt

Not all hacks need to be made up of servo motors, wireless radios, and PIR sensors. Sometimes hacking has a softer side, of which [Katie] reminds us with her latest creation.

Her LED quilt incorporates 64 hand-sewn LEDs, all of which were painstakingly attached with conductive thread. The same thread was used in a sewing machine to build the conductive grid that powers the LEDs. One half of the circuit was sewn into the front of the quilt in the form of 8 rows, while the columns are sewn into the back side. All of the rows and columns meet in the corner of the quilt, where they are attached to a Lilypad Arduino using simple metal snaps.

The LED matrix panel was then tested, then sewn into an actual quilt. The finished product looks completely innocuous until lit up, as you can see in the video below. We think it would make a great nightlight replacement for a child, especially if programmed to display soothing light patterns.

[via Make]

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Designing A Controllable RGB LED Driver Board

March 30, 2011 by Mike Szczys 16 Comments

[Paul] wrote in to tell us about this LED driver board he’s been working on with a few friends. The collaborators had been unhappy with the Lumens per Watt ratings (or lack of a rating) on low powered LEDs and set out to find a better solution. They picked up the beefy ASMT-MT00 which houses all three diodes in one package, with all the pins on one side of the surface mount package, a heat dissipating tab on the other side, and pushed 30 Lumens per Watt. With that in hand they set out to design a host board for the blindingly bright light.

The board includes a heat sink on the underside. To drive the LEDs [Paul] sourced an LM3407 constant current driver. The manufacture recommends using one of these chips for each of the colors in the LED package. [Paul] built a circuit that allows him to route power around each LED, making the system work with just one low-side driver. From there, an ATtiny2313 provides addressable control via the RS485 protocol. Screw terminals on either end of the PCB allow this to be chained along with other modules, and they’ve already worked out a basic PureData program that will be able to address multiple boards once they finish manufacturing them.