TV Ambient Lighting Built For Awesome Performance

June 11, 2021 by Lewin Day 36 Comments

[AndrewMohawk] had seen all kinds of ambient lighting systems for TVs come and go over the years, and the one thing they all had in common was that they didn’t live up to his high standards. Armed with the tools of the hacker trade, he set about building an Ambilight-type system of his own that truly delivered the goods.

The development process was one full of roadblocks and dead ends, but [Andrew] persevered. After solving annoying problems with HDCP and HDMI splitters, he was finally able to get a Raspberry Pi to capture video going to his TV and use OpenCV to determine the colors of segments around the screen. From there, it was simple enough to send out data to a string of addressable RGB LEDs behind the TV to create the desired effect.

For all the hard work, [Andrew] was rewarded with an ambient lighting system that runs at a healthy 20fps and works with any HDMI video feed plugged into the TV. It even autoscales to work with video content shot in different aspect ratios so the ambient display always picks up the edge of the video content.

With 270 LEDs fitted, the result is an incredibly smooth and fluid ambient display we’d love to have at home. You can build one too, since [Andrew] shared all the code on Github. As an added bonus, he also gave the system an audio visualiser, and tested it out with some Streetlight Manifesto, the greatest third-wave ska band ever to roam the Earth. The Fourth Wave still eludes us, but we hold out hope.

We’ve seen plenty of hacks in this vein before; one of the most impressive hacked a smart TV into doing the video processing itself. Video after the break.

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TV Detector Vans Once Prowled The Streets Of England

January 18, 2021 by Lewin Day 307 Comments

The United Kingdom is somewhat unique in the world for requiring those households which view broadcast television to purchase a licence for the privilege. Initially coming into being with the Wireless Telegraphy Act in 1923, the licence was required for anyone receiving broadcast radio, before being expanded to cover television in 1946. The funds generated from this endeavour are used as the primary funding for the British Broadcasting Corporation.

A typical TV licence invoice. Separate licences for black and white and color sets still exist, with 6000 B&W licences issued in 2019.

Of course, it’s all well and good to require a licence, but without some manner of enforcement, the measure doesn’t have any teeth. Among other measures, the BBC have gone as far as employing special vans to hunt down illegally operating televisions and protect its precious income.

The Van Is Coming For You

To ensure a regular income, the BBC runs enforcement operations under the TV Licencing trade name, the entity which is responsible for administering the system. Records are kept of licences and their expiry dates, and investigations are made into households suspected of owning a television who have not paid the requisite fees. To encourage compliance, TV Licencing regularly sends sternly worded letters to those who have let their licence lapse or have not purchased one. In the event this fails, they may arrange a visit from enforcement officers. These officers aren’t empowered to forcibly enter homes, so in the event a homeowner declines to cooperate with an investigation, TV Licencing will apply for a search warrant. This may be on the basis of evidence such as a satellite dish or antenna spotted on the roof of a dwelling, or a remote spied on a couch cushion through a window.

Alternatively, a search warrant may be granted on the basis of evidence gleaned from a TV detector van. Outfitted with equipment to detect a TV set in use, the vans roam the streets of the United Kingdom, often dispatched to addresses with lapsed or absent TV licences. If the van detects that a set may be operating and receiving broadcast signals, TV Licencing can apply to the court for the requisite warrant to take the investigation further. The vans are almost solely used to support warrant applications; the detection van evidence is rarely if ever used in court to prosecute a licence evader. With a warrant in hand, officers will use direct evidence such as a television found plugged into an aerial to bring an evader to justice through the courts.

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Haunted TV Does Mirror Scares With Raspberry Pi

November 13, 2020 by Lewin Day No comments

Hallowe’en may be over for another year, but that just means you’ve got more time to prepare your build for next time. [gocivici] has a fun twist on the classic mirror scare that might be just up your alley.

The build starts with an old black and white TV, hooked up to a Raspberry Pi 3. The Pi films the scene in front of the television through a camera secreted into the screen’s headphone jack, and displays it on screen. The camera feed is run through OpenCV, which runs face and eye detection algorithms to determine when a person is looking at the screen. Based on a basic timer script, when a viewer has looked long enough, a ghostly apparition is displayed, lurking behind the viewer. When the user looks over their shoulder, the apparition quickly disappears, as per the classical horror trope.

It’s a fun build that would make an excellent set piece for your next Hallowe’en party. For extra effect, be sure to secret it down a dark hallway with some IR LEDs illuminating the scene for the camera only. If you prefer something with a little more whimsy, consider these animated singing pumpkins instead. Video after the break.

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VR Technology Helps Bring A Galaxy Far, Far Away To Our TV

August 27, 2020 by Roger Cheng 18 Comments

Virtual reality is usually an isolated individual experience very different from the shared group experience of a movie screen or even a living room TV. But those worlds of entertainment are more closely intertwined than most audiences are aware. Video game engines have been taking a growing role in film and television production behind the scenes, and now they’re stepping out in front of the camera in a big way for making The Mandalorian TV series.

Big in this case is a three-quarters cylindrical LED array 75 ft (23 m) in diameter and 20 ft (6 m) high. But the LEDs covering its walls and ceiling aren’t pointing outwards like some installation for Times Square. This setup, called the Volume, points inward to display background images for camera and crew working within. It’s an immersive LED backdrop and stage environment.

Incorporating projected imagery on stage is a technique going at least as far back as 1933’s King Kong, but it is very limited. Lighting and camera motion has to be very constrained in order to avoid breaking the fragile illusion. More recently, productions have favored green screens replaced with computer imagery in post production. It removed most camera motion and lighting constraints, but costs a lot of money and time. It is also more difficult for actors to perform their roles convincingly against big blank slabs of green. The Volume solves all of those problems by putting computer-generated imagery on set, rendered in real time via video game engine Unreal.

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Trick From 1903 Makes An Old Monochrome TV Spit Some Colours

July 28, 2020 by Adil Malik 26 Comments

Its safe to say that colour television is taken for granted nowadays. Consumed by the modern marketing jargon of colour dynamic range, colour space accuracy and depth, it is easy to overlook the humble beginnings of image reproduction when simply reconstructing an image with the slightest hint of colour required some serious ingenuity and earned you a well deserved pat on the back!

[anfractuosus] revisited an old gem of a technique, first patented in 1903 and used it to successful make an old monochrome TV produce a colour image. The idea in essence, is actually similar to what cheap image sensors and LCDs still use today. Rather than relying on true RGB colour generation by individually integrating colour sources as AMOLED does, we take an easier route: Produce a simpler monochrome image where each colour pixel is physically represented by four monochrome sub-pixels, one for each colour component. Now light up each of the sub-pixels according to the colour information of your image and rely on an external colour filter array to combine and spit out the correct colours.

He first used some image processing to convert a standard colour video into the aforementioned monochrome sub-pixel representation. Next, a Bayer colour filter array was printed on some acetate sheets using an inkjet printer (the original inventors used potato starch!), which when overlaid on top of the monochrome monitor, magically result in colour output.

There are some problems associated with this technique, mainly to do with the difficulty in measuring the size of the TV pixels and then producing and perfectly aligning a filter sheet for it. You should check out how [anfractuosus] went about solving those issues.

So now you know a bit more about colour image generation, but how about colour TV transmission? Check out an earlier piece to learn more.

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Turn Your Old-school CRT Into A YouTube Media Player

October 20, 2019 by Sharon Lin 40 Comments

Ever wish you could enjoy modern conveniences like YouTube in a retro world of CRTs and late 20th century graphics?

[Johannes Spreitzer] happened to find an old VIENNASTAR CRT (cathode-ray tube television) made by the Austrian brand Kapsh at a flea market. The CRT dates back to 1977 and uses just RF input, making it useless as a modern television set since most TV stations nowadays broadcast primarily in digital.

However, HDMI-to-RF transmitters do exist, making it possible to convert HDMI signals to RF or coaxial cable output to replace an antenna signal. What [Spreitzer] did next was to plug in a Chromcast and essentially convert the CRT into an old-school monitor. You can see some of the trippy graphics in the video below – the video samples shown fit the retro aesthetic, but I’m sure there’s video combinations that would seem pretty out of place.

HDMI-to-RF adapters are pretty easy to pick up at a hardware store, and they allow you to project videos onto specific channels on a CRT. Needless to say, they don’t work the other way around, although since there are still televisions that only pick up RF broadcasts, coaxial to HDMI adapters do exist.

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Retrotechtacular: History Of Sony Mini Doc Bursts With 1970s Style

May 10, 2019 by Drew Littrell 16 Comments

The 1970s, it was a time when cameras needed film, phones had cords, and televisions masqueraded as furniture. A time where hi-fi systems were judged by the volume knob feel, and thanks to YouTube user [nefesh22] we have a behind-the-scenes glimpse of what the era was like from the Sony corporate perspective in this mini documentary of the company’s history below. The film was originally created for internal use at Sony’s US manufacturing facilities in San Diego, however, now it now can be watched by anyone with an internet connection.

Sony’s corporate ethos of allowing its engineers to drive business innovation is on full display here. For instance how in 1950 Sony introduced the first magnetic tape recorder, the G-Type, in Japan and followed that up with the first portable television, the TV8-301, a decade later. Throughout the 1970s Sony became an innovator in the video space. In fact, the Sony Trinitron brand of color TVs garnered so much notoriety in the television industry that the company was awarded an Emmy in 1973. Though the most telling feature is the documentary’s focus on the 3/4-inch U-Matic videocassette format, a precursor to VHS and Sony’s own Betamax videotapes. Highlighting the “superiority” of those VTR systems of the day really does date the film as those hulking decks failed to penetrate the market beyond early adopters and media companies.

It’s interesting to see how hands-on quality assurance testing used to be. Whether it’s glancing at NPN transistors under a microscope, dialing in the focus on a Super 8 camera, or a quick wave of the degaussing wand before a tube leaves the line, each of the QA tasks were carried out by individual employees rather than the automated methods of today. On an unrelated note, the brief overview of the Sony’s on-site “fiefdom” for its young workforce is a reminder that some ideas may be better left in the past… Google’s Mountain View campus anyone? If anything is to be gleaned from this retrotechtacular retrospective is that we could all use a little more wood-grain in our electronics these days.

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