In the neighborhood

He had to appear at one time or another, here is our friendly neighbor Totoro making a special appearance in my apartment during the latest light painting session:

How it’s done v2

The liightbrush v2 is an interactive light painting tool. Made of a 1 meter long LED strip, it changes color based on where it is positioned in space according to a user selected picture. You can move the brush along, in whatever orientation/direction, and it will “paint” the global appearance of the target image.

Here is an example of a light painting session, and its result:

There are three main parts to the project:

The camera: used to take the pictures, in “bulb” mode in order to have an exposure time as long as necessary, with a remote to make operations simpler. I am currently using a Canon 550D.

The wiimote: the most basic part of it all, as it is a standard Nintendo wiimote

The computer: bluetooth enabled computer, that receives  from the Wiimote the current position of the liightbrush. A bit of C# code then computes what are the adequate colors to be displayed, and sends them over serial port to the liightbrush

The liightbrush itself is a combination of:

• a LED strip (with by the LPD8806 chip instead of the HL1606 of the first version), allowing control of individual LEDs with a wide spectrum of colors
• an Arduino Mega, receiving data from the Serial link to the PC and sending it properly to the LED strip. I use the great SPI libraries to pilot the LEDs (http://forums.adafruit.com/viewtopic.php?f=47&t=22982)
• a bluetooth module connected to the Arduino in order to make the Serial link wireless
• Infrared emitters, extracted from a wireless Wii sensor bar, placed at each extremity of the liightbrush in order to allow the wiimote to “see” it
• An aluminum rod, a plastic box, a battery pack, duct tape, bolts and wire

Watch Out

The design is complete, the software has a brand new GUI to set up the liightpainting, so watch out for a lot of new stuff as soon as I get a minute for it!

Malynx!

The last bug has been identified (I was sending messages over the serial link simultaneously from separate threads, mixing their data). I now have a fully loaded and operational liightbrush to have fun with. Malynx Le Lynx !

Not on a plane

It’s done! I now officially have a working version 1 of the liightbrush. I have cut it down to 32 LEDs as I was having issues over that number, but it now works in a fully wireless way. As you can see on the picture below, I would highly recommend against trying to board a place with such a device on yourself

Wireless Squarepants

I unfortunately do not have an appartment large enough to use a 2 meters wide lightpainting appartus, but I still managed to run a few tests that are showing great promises, even with some significant day light. It appears that there is a “ghost” duplicate image, I have not figured out yet if that was due to the reflection of the IR emitters, the source image, or my code. I’ll have to look into that in more details.

Version 2

Took me quite some time, but here is at last v2 of the liightbrush. There are the main improvements:

LEDs using the newer LPD8806 chips allowing built in handling of a much wider scope of colors

2 meters long, with 64 LEDs (instead of 8 previously)

Wireless bluetooth for serial input

Built in IR emiters powerd through the Arduino (ripped from a Nintendo Wii sensor bar)

Much optimized Arduino code

Foldable aluminium design for easy transportation of the Liightbrush

But it is still not over yet as I still need:

To power the device without relying on the USB chord (which kinds of defeat the whole bluetooth work)

To find a proper material to scatter the LED lights, that are a bit too bright

Think Big

Back to work, the time I can spend on the liightbrush is now seriously limited. Nonetheless, the v2 is on the way, with almost 7 times more LEDs (as shown below) and wireless connection to the PC through bluetooth. I am still looking around for proper material to scatter the light. Most parts should be in late this week, and I am targeting to get the work done by the end of next week.

Music at the crossing

A request for an animal crossing character came in, which I couldn’t refuse. This picture teaches something valuable: a black background on a picture isn’t always as black as I would want it to be. I need to ensure that it is true black in order for it to be completely transparent, otherwise there might be some lost pixels, basically black to the eye but that get translated to colored LEDs nonetheless, as seen with the blue dots below.

As a bonus (lucky you), here is a mix of yesterday’s two pictures.

Moonwalker

Confined spaces make the picture that much more real thanks to the reflections, but at the same time that much more surreal (go figure). The picture below is named “got lost?”, because giving it a name just make it seem like it’s art.

Neighbors are beginning to wonder what are these flashing lights at night. And when there’s something strange in the neighborhood, who are you gonna call? (thanks Nicolas for the idea).