Light Graffiti with Servos and Python

servo-laser-light-graffiti

Light Graffiti is can be lots of fun if you have a decent amount of artistic ability, and a keen sense of timing. If you don’t have the necessary skills, you can always compensate by using Python-controlled servos to move everything automatically. The Python code can be found here, and makes use of the Python Image Library to process the images into a “drawable” form. A [pyMCU] with firmware capable of simultaneous servo control was used to move the laser fixture around.

One of the more difficult aspects of this experiment was getting the timing correct between each laser pulse. The timing routine involes a bit of geometry, calculating the distance between each using trig. As explained in the article, this may be a bit of overkill.  It still didn’t compare to the trig involved in a previous experiment drawing a circle with this laser-servo fixture.  Be sure to check out the video of this laser-setup in action after the break.  I’ve been quite pleased with the results, and look forward to what can be done with it in the future!

Thanks to [pyMCU] for letting me have a few of these boards to play with!

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LED fun and Light Painting with the pyMCU

pymcu-led-pov-writing

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. [Read more...]

LED wand brings ergonomics to light painting

Quit struggling with hastily patched together electronics for your light painting images. Follow [Madox's] example and build a light painting wand designed with your hand in mind.

You wield it much like a sword, but the only damage it does is to the long-exposure camera pointed its way. The RGB LED strip is controlled by the guts of a tiny little wireless router, a TP-Link TL-WR703N. This lets [Madox] connect using an Android device to upload different images. It also lets you tweak the settings like adjusting the timing between columns to match your exposure settings. The custom handle design provides a home and mounting plan for everything involved. It was 3D printed at the Sydney Hackerspace.

This isn’t the first light painting device running Linux. We’ve actually seen the Raspberry Pi used in much the same way but that final project involved using an entire recumbent tricycle to move the colored lights.

Cloning a water-based light wall project

A few weeks ago, we featured this water-based LED graffiti art installation that allows anyone to paint in light using only a bottle of water. When one of [Chris]‘ friends saw the video of this build, he immediately asked him how it worked. One thing led to another, and now [Chris] and a few other members at the BUILDS hackerspace at Boston University are building their own water LED installation.

The basic premise of this build is allowing water to serve as a conductor between the anode and cathode of a LED. Without spraying or painting water on the circuit [Chris] whipped up, there is an infinite resistance between the two pins of the LED and current cannot flow. After applying water to the anode and cathode pads, a small amount of current is conducted through the water and the LED lights up.

Right now, [Chris] is working on a test board with different sizes of pads and spacing to get the best water graffiti LED effect for his future build. The plan is to build a single one-meter panel out of one hundred 10 cm x 10 cm boards connected together with jumpers.

All of [Chris]‘ work is up on GitHub, and even though [Chris] hasn’t begun designing the production boards, it’s more than enough to get you started if you’d like your own water LED painting panel.

Light painting with the Raspi

The art of taking long exposure photographs with blinking RGB LEDs has improved greatly over the years, mostly due to the extremely easy to use Arduino and hundreds of tutorials on the web. If there’s one problem with light painting with a ‘duino, it’s that large, full color images take up a ton of storage space, much more than the flash memory on an Arduino can provide. Wanting fancier and more colorful light painted images, [Phil] over at Adafruit used a Raspberry Pi to make some very awesome light painted images.

Like any Adafruit tutorial that uses LEDs, the build begins with a digital RGB LED strip wired to the GPIO pins on the Raspi. After loading up the Adafruit educational Raspi Linux distro for hardware SPI support, the only thing left to do was writing a Python script to display images in the air.

[Phil] says vertical, hand-held LED bars are old hat, so he took a hula hoop and a few bits of PVC pipe, attached the LED strip, and put it on his bike. The results are really impressive – we’re loving the flames in the title pic – and considering the Raspi is a full-fledged computer, light paintings larger than what [Phil] made are very possible.

Simple light painting bar build

[SkyWodd] took the easy route when it came time to build this light painting bar. But he was still met with great success. Thanks to his well-documented work you should be able to throw this together for yourself in about an hour.

The idea here is to build a full-color display that will draw a picture in a long-exposure photograph. We’ve seen the concept used with 64 discrete RGB LEDs, but there’s almost no soldering to be done with this project. Instead, [SkyWodd] used an addressable RGB LED strip. It has 64 pixels, all taking commands via the SPI protocol. This helps keep the number of microcontroller connections to a minimum. He lashed the entire system onto a long hunk of wooden dowel and grabbed a camera.

You’ll need a DSLR as each image needs to have an exposure time approaching 10 seconds. One thing to note is that it may be best to leave the LED bar stationary and move the camera. If you use a tripod it should help keep the vibrations to a minimum.

Laser light painting includes camera control

This laser light painting setup can even control the camera. But it probably will not work with your average point-and-shoot. The exposure time used is somewhere around 2 seconds long, a feature which is hard to find on anything but DSLR cameras.

The setup relies on a red laser diode to do the painting. When viewed in real time you only see a dot tracing out a cryptic pattern and occasionally switching on and off. But with a long exposure the intense light persists to achieve an image like the one seen above. Note the ghosting around the rig as it has moved while the shutter was open.

The Arduino controlled device consists of a base which pivots the diode horizontally, with a servo for aiming on the vertical axis. Since the sketch is divided up by letter, we wonder how hard it would be to adapt this for use with a point-and-shoot? Perhaps you could capture one letter at a time and layer the frames in post production?

It seems this is a lot easier to build than some of the LED plotters we’ve looked at. If you do make your own don’t forget to send a link our way.

[Read more...]

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