Light painting Nyan Cat with an Arduino

You too can paint your favorite meme in light with just a few tools. [Skywodd] brought together a couple of different projects to make this happen. He had already built a large POV display and now uses a DSLR with long exposure to create light paintings (translated).

The Arduino-powered display is built from a strip of 35 RGB LEDs. Now, that’s four pins per LED but one of is ground, leaving just 105 pins that need to be addressable. A couple of things make this manageable. First, he etched his own circuit boards for the LED strips. This breaks out the contacts to the edge of the boards and simplifies the soldering a bit by taking care of the ground bus. Secondly, he’s using M5450 LED display drivers for addressing. After the break you can see the video of the prototype hardware (in French but blinky action starts at about 2:30).

If you’re looking for an easier way to do this, check out the light painting that uses manufactured LED strips.

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Cheap Acoustic Panel DIY

[Eric Wolfram] wrote in to let us know about a simple and cheap acoustic panel DIY he put together.  When installing a home theater acoustics are often neglected (especially if you spend so much on the TV you cannot afford any furniture for the room) resulting in reduced listening quality and poor spacial sound imaging from your surround system (also responsible for the furniture problem). The addition of sound absorbing panels helps control the acoustics of the room and may even class up the place a bit.  These are also come in handy for home studio usage where a low level of reverberation is preferred.

The panels are relatively simple to produce on a budget, just a sheet of 2″ thick dense fiberglass board glued into a wooden frame and covered in a sound-transparent fabric. [Eric] goes into a lot of the material selection process to help you along your way. The best part about the project (aside from its obvious utility) is that all of the materials can be found cheaply at your average home improvement store, with the exception of the fabric.  [Eric] mentions that you can substitute colored burlap if need be.  Once the panel is assembled and glued it just has to be hung on the wall of your choice like a large heavy picture frame. This could certainly help the acoustics and reduce some slap-back echo in your warehouse/shop. We might have to try this one over the weekend.

Thanks [Eric]!

A very simple Android recon vehicle

Desperately in need of a graduation paper, [Andrei] decided to build a few computer controlled recon vehicles (PDF warning), and we’re really impressed with the minimalist approach [Andrei] took.

The Computer Operated Recon Entity (C.O.R.E.) mk. I is based around a laptop. Instead of an Arduino, [Andrei] used a car stereo amp to control the motors. The two channel amp [Andrei] picked out has four outputs. Tying a motor to each output gives a four-wheel drive robot that’s really clever in its simplicity. With an onboard webcam, [Andrei] can do live video streaming from his remote vehicle. Outputting a specific tone with the sound card allows for full control of the robot.

The C.O.R.E. mk. II uses a Samsung Galaxy I5500 phone – the cheapest Android phone [Andrei] could find. The setup is similar to the mk. I C.O.R.E. with a WiFi connection sending video back to a base station. Control of the two motors is still handled by playing sound files and sending that to a stereo amp connected to the motors.

Check out the C.O.R.E. mk. II going Bach and forth after the break.

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Extending battery life while taking time lapse photos


[Peter] loved using his GoPro HD camera, but he found the time lapse functionality a bit lacking. It wasn’t that there were not enough settings to satiate his needs, but that the camera would run through its batteries in just a few short hours.

He found that the camera did not turn off or enter any sort of sleep mode between shots, wasting precious battery life. He could have simply added a bigger external battery pack to the camera, but for the sake of portability, he had a far better idea in mind.

The GoPro has a pretty well documented interface called the “Hero Bus”, so all it took was a little bit of online research before [Peter] had all the information he needed. The camera has a neat feature that immediately snaps a picture when it is powered on, so he decided that he would use a microcontroller to turn the camera on and off at specific intervals, rather than using its built-in time lapse function. He chose a Texas Instruments MSP430 for the job, since it is very well known for being a power miser.

Once he had his code up and running, he connected it to his camera and found that it worked perfectly right off the bat. Now, he can take anywhere between 1,500 and 2,000 shots before the batteries run out, instead of the measly 200 he was getting without the modifications – quite an improvement!