Month: May 2016

Using An FPGA To Generate Ambient Color From Video

May 20, 2016 by 4 Comments

We should all be familiar with TV ambient lighting systems such as Philips’ Ambilight, a ring of LED lights around the periphery of a TV that extend the colors at the edge of the screen to the surrounding lighting. [Shiva Rajagopal] was inspired by his tutor to look at the mechanics of generating a more accurate color representation from video frames, and produced a project using an FPGA to perform the task in real-time. It’s not an Ambilight clone, instead it is intended to produce as accurate a color representation as possible to give the impression of a TV being on for security purposes in an otherwise empty house.

The concern was that simply averaging the pixel color values would deliver a color, but would not necessarily deliver the same color that a human eye would perceive. He goes into detail about the difference between RGB and HSL color spaces, and arrives at an equation that gives an importance rating to each pixel taking into account its saturation and thus how much the human eye perceives it. As a result, he can derive his final overall color by looking at these important pixels rather than the too-dark or too-saturated pixels whose color the user’s eye will not register.

The whole project was produced on an Altera DE2-115 FPGA development and education board, and makes use of its NTSC and VGA decoding example code. All his code is available for your perusal in his appendices, and he’s produced a demo video shown here below the break.

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Networked Solar Birdhouses Deep In The Woods

May 20, 2016 by 6 Comments

[Oitzu] in Germany wrote in to let us know about a series of short but very informative blog posts in which he describes building a series of solar-powered, networked birdhouses with the purpose of spying on the life that goes on within them. He made just one at first, then expanded to a small network of them. They work wonderfully, and [Oitzu]’s documentation will be a big help to anyone looking to implement any of the same elements – which include a Raspberry Pi in one unit as a main gateway, multiple remote units in other birdhouses taking pictures and sending those to the Pi over an nRF24L01+ based radio network, and having the Pi manage uploading those images using access to the mobile network. All with solar power.

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Toy Piano Gets Synth Overhaul

May 20, 2016 by 7 Comments

The Peanuts cartoon character Schroeder liked to bang out Beethoven a toy piano. Now, thanks to this hack from [Liam Lacey], Schroeder can switch to Skrillex. That’s because [Liam] built a polyphonic synth into a toy piano. It’s an impressive build that retains the look and feel of the piano, right down to a laser-etched top panel with knobs that match the glossy black styling.

The brains of the synthesizer is a Beaglebone Black using the Maximillian synthesis library. To capture the key presses, he used Velostat, a pressure-sensitive material that changes resistance under pressure. This is probably the only toy piano in the world with fully polyphonic velocity and aftertouch. The build also includes MIDI support, with two ports on the back. [Liam]’s build log is full of more details than we can even summarize here.

This beautiful build won [Liam] first place in the Element 14 Music Tech competition, and it is a well-deserved prize for a clean and elegant way to update a vintage piano.

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Evolving Storytelling To Marry The Ancient Skills With The Digital Age

May 20, 2016 by 50 Comments

Storytelling is an art. It stretches back to the dawn of man. It engages people on an emotional level and engages their mind. Paulina Greta Stefanovic, a user experience researcher and interaction designer is on the cutting edge of bringing our technology together with the best human aspects of this long tradition.

The information age is threatening storytelling — not making it extinct, but reducing the number of people who themselves are storytellers. We are no longer reliant on people in our close social circles to be exquisite story tellers for our own enjoyment; we have the luxury (perhaps curse?) of mass market story-telling.

Paulina’s work unlocks interactive storytelling. The idea isn’t new, as great storytellers have always read their audience and played to their engagement. Interactive storytelling in the digital age seeks to design this skill into the technology that is delivering the story. This is a return from passive entertainment.

This breaks down into interactive versus responsive. At its simplest, think of responsive as a video that has a pause button. You can change the flow of the story but you can’t make the story your own. Surprisingly, this is a new development as the ability to pause playback is but a few decades old. So you can pause a responsive medium, but true interactive experiences involve creation — the audience is immersed in the story and can make substantive changes to the outcome during the experience.

This equates to a power transfer. The creator of the media is no longer in complete control, ceding some to the audience. We are just at the start of this technology and it looks like the sky is the limit on what we can do with algorithmic interactions.

Video games are the forerunners of this change. They already have branching stories that let the users make choices that greatly affect the storyline. This industry is huge and it seems obvious that this active aspect of story consumption is a big part of that success. Even more intriguing is a “drama management system” (a new term to me but I love it) that results in a story whose ending nobody knows until this particular audience gets there. What a concept, and something I can’t wait to see for myself!

If you find these concepts as interesting as I do, check out Paulina’s talk below, which she presented at the Hackaday Belgrade conference.

Hackaday Dictionary: Lithium Ion Batteries

May 20, 2016 by 36 Comments

Battery technology is a constant chemical war between the laws of physics and the desire of engineers to make devices smaller. On one side, the laws of physics declare that there are limits to how much energy you can store inside a battery, and on the other side are the engineers looking for ways to sneak around these laws. For many devices, the best compromise between these two sides is the lithium ion battery, usually abbreviated to Li-ion.

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A Better Mousetrap, At Least For The Mouse

May 20, 2016 by 61 Comments

No mice were harmed in the making of this non-lethal soda bottle mousetrap.

Depending on your opinion of these little critters, that could be a good thing or a bad thing. We don’t deny that mice are cute as all get-out, but when they do damage to foodstuffs that you’ve put an entire summer’s effort into growing, harvesting and preserving, cute isn’t worth much.

Our preference for taking care of rodent problems is either bioremediation or rapid cervical dislocation, but if you’re more of the catch-and-release type, this trap is for you. It’s just a 2-liter soda bottle on a wire pivot and mounted to a scrap wood frame; when the offending critter unwisely enters the neck of the bottle, its weight flips the bottle down and blocks the exit. Release is as simple as removing the bottle from the frame and letting Monsieur Jingles wiggle free. The questions of where to release and how many times you’ll keep catching the same mouse are left as an exercise for the reader.

Remember – a live catch trap is only humane if it’s checked regularly. To that end, maybe something like das Katzetelegraf could be added to this trap.

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Virtually Free Rapsberry Pis

May 20, 2016 by 54 Comments

One of the nice things about the Raspberry Pi is that it runs Linux and you can do a lot of development right on the board. The converse of that is you can do a lot of development on a Linux desktop and then move things over to the Pi once you get the biggest bugs out. However, sometimes you really need to run code on the actual platform.

There is, however, an in-between solution that has the added benefit of upping your skills: emulate a Pi on your desktop. If you use Linux or Windows on your desktop, you can use QEMU to execute Raspberry Pi software virtually. This might be useful if you don’t have a Pi (or, at least, don’t have it with you). Or you just want to leverage your large computer to simplify development. Of course we would be delighted to see you build the Pi equivalent of the Tamagotchi Singularity but that’s a bit beyond the scope of this article.

Since I use Linux, I’m going to focus on that. If you insist on using Windows, you can find a ready-to-go project on Sourceforge. For the most part, you should find the process similar. The method I’ll talk about works on Kubuntu, but should also work on most other Debian-based systems, including Ubuntu.

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