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.
Continue reading “Using An FPGA To Generate Ambient Color From Video”
If there’s a better use for Raspberry Pi Zero than a shuffler for episodes of “The Simpsons”, we haven’t heard about it.
Creator [Stephen Coyle] took inspiration from [Will Smith]’s mention of the burning need for such a device on the Tested podcast years back. The gadget is just a Zero with a familiar yellow button – hopefully it’s Pantone 116 C – that randomly selects an episode from the SD card. [Stephen] is clear on his opinion of over half of the program’s oeuvre, having found only seasons 2 through 10 worthy to load on the card. As an aside, we feel pretty old after seeing that all 593 episodes can easily fit on a 128GB SD card – we started out religiously recording every episode on VHS tapes, but had to stop after a few seasons when the collection got too big to handle.
If ripping episodes from DVDs isn’t your style, or you’re still into the first-run stuff, you might want to check out this confusingly named Smart Homer so you never miss an episode.
Continue reading “Rasberry Pi Zero Plays Every Simpsons Episode Ever at Random”
[Kevin Darrah] put together a good video showing how to control a stepper motor with, not a motor driver, but our fingers. Taking the really low-level approach to do this sort of thing gave us a much better understanding about the features of our stepper driver chips. Such as, for example, why a half step needed twice the current to operate.
[Kevin] starts with the standard explanation of coils, transistors, and magnets that every stepper tutorial does. When he hooks up simple breadboard with passives and buttons, and then begins to activate the switches in sequence is when we had our, “oh,” moment. At first even he has trouble remembering the correct sequence, but the stepper control became intuitive when laid out with tactile switches.
We set-up our own experiment to see if we remembered our lessons on the subject. It was a fun way to review what we already knew, and we learned some more along the way. Video after the break.
Continue reading “Get Really Basic With Steppers and Eight Buttons”
Even though VGA is an outdated and becoming somewhat deprecated, getting this video output running on non-standard hardware is a rite of passage for some hackers. [Andrew] is the latest to take up the challenge. He got VGA output on a Freescale i.MX233 and also got some experience diving into the Linux kernel while he was at it.
The Freescale i.MX233 is a single-board computer that is well-documented and easy to wire up to other things without specialized hardware. It has video output in the form of PAL/NTSC but this wasn’t quite enough for [Andrew]. After obtaining the kernel sources, all that’s needed is to patch the kernel, build the kernel, and build a custom DAC to interface the GPIO pins to the VGA connector.
The first thing that [Andrew] did was load up the Hackaday home page, which he notes took quite a while since the i.MX233 only runs at 454 MHz with just 64 MB of RAM. While our retro page may have loaded a little faster, this is still an impressive build and a great first step to exploring more of the Linux kernel. The Freescale i.MX233 is a popular chip for diving into Linux on single-board computers, and there’s a lot going on in that community. There are some extreme VGA hacks out there as well if that’s more your style.
This great old video (embedded below the break) from Tektronix in the mid-60s covers a topic that seems to confuse folks more than it should — transmission lines. We found it on Paul Carbone’s blog, a great site for aficionados of old analog scopes in its own right.
As with many of these older videos, the pacing is a bit slow by today’s standards, but the quality of the material eventually presented more than makes it worth the effort to reign in your ADHD. For a preview, you can skip to the end where they do a review of all the material.
They start off 5:31 with a pulse travelling down a wire pair, and take a very real-world approach to figuring out the characteristic impedance of the line: if the pulse was created by a battery of 9V, how much current is flowing? If the DC resistance of the wire is zero then there should be an infinite current by Ohm’s law, and that’s clearly not happening. This motivates the standard analysis where you break the wire down into distributed inductance and capacitance.
Of course they do the experiment where you inject a pulse into a long loop of coaxial cable and play around with the termination at the other end of the line. They also measure the velocity factor of the line. Our only gripe is that they don’t tap the line in different places to demonstrate standing waves. The good news is that we’ve got YouTube (and [w3aew]) for that.
If you’ve got 23 minutes to spare, and are curious about transmission lines or just enjoy the soothing voice of a trained radio announcer reading out values of various termination resistors, this old gem is just the ticket. Enjoy!
Continue reading “Retrotechtacular: Transmission Lines”
[Saulius Lukse] has a really interesting way of turning a couple of buildings into his own addressable display. The effect is not seen in real life, but is a clever video rendering with stock he pulled from time-lapse cameras. Now if you want to play Tetris using the windows of a building you add wireless lightbulbs to every window. But that’s a lot of work. You can fake playing Tetris (or scrolling messages in this case) if you just show a video of the buildings and swap in your own image manipulation.
[Saulius] starts with a time lapse sequence of a city scape. It needs to be one with a large building or two to provide a good scrolling surface. The building is extracted from the scene with the background transparent. The really time consuming part is creating a distinct image with one window lit for each window that is going to be used. This set of windows are the ‘pixels’ used to create the scrolling images. This is accomplished by masking out one image of the building with every office light turned off, then masking out each window individually with the office illuminated. This masking means everything going on around the building (traffic, weather, people) will be preserved, while the windows can be individually manipulated.
Next the program jinx is used to create the building animation. This program is designed to create scrolling messages on LED panels. [Saulius] provides a Python script that takes the images, the output of jinx, and combines them to create the final set of moving images.
The result is a city wishing you a “Happy New Year!”
Continue reading “Scrolling a Message on a Building in a Time Lapse Video”
Spend enough time on YouTube, and you’ll eventually find yourself in one of the many dark corners hiding within it. No, I’m not talking about the comments. In this case, I mean the many videos dedicated to free energy, overunity devices, perpetual motion machines, or anything else that violates the laws of thermodynamics by trying to get out more energy than is put in. The human race has been reaching for impossible dreams of perpetual motion and free energy for just about all of recorded history. Now it’s convenient to find them all in one place.
Browsing the tubes, it’s easy to break free energy videos down into two major groups: enthusiasts and scammers. Catching a scammer is easy – they’re looking for money. Somewhere in the video or description will be a link to a website with more information. Eventually that will lead you to a place where the scammer attempts to part you and your hard-earned money.
Names like John Searl, Muammer Yildiz, and M. T. Keshe go here. Searl especially deserves note because he’s been at it for decades. Supposedly, his “Searl Effect Generator” SEG has been built several times, but the prototypes generate so much power they create their own anti-gravity field and fly off into space. Obviously this man and his staff need your money to continue their work. Scammers deserve disdain and public shaming. These are the folks who know their “discoveries” are nothing more than snake oil.
On the other side of the coin lie the enthusiasts. These are the backyard tinkerers, the ones who put down their computers, pick up their tools, and try to build something. Sounds a lot like the average Hackaday reader, doesn’t it? I have to admit I went into this article with the same disdain for the enthusiasts that I have for the scammers, possibly even more. In some cases, these are the folks who truly believe they can have a chance to violate the laws of thermodynamics. Inevitably these folks fail to build free energy generators, overunity devices, or whatever their pursuit is, but they all do seem to learn something in the process. A lot can be said about the builds themselves. Some of these are awesome devices. Even if they don’t work for their intended purpose, they are great demonstrations of magnetism or chemistry. This is where I had a change of heart. If someone wants to spend their time working on an impossible hack, then more power to them. I may not think they have any chance of success, but at the very least, they’ll learn how to build.
Continue reading “Overunity, Free Energy and Perpetual Motion: The Strange Side of YouTube”