TVs are usually something you sit and passively watch. Not so for [Nate Damen’s] interactive, wearable TV head project, aka Atltvhead. If you’re walking around Atlanta, Georgia and you see him walking around with a TV where his head should be, introduce yourself! Or sign into Twitch chat and take control of what’s being displayed on the LEDs which he’s attached to the screen. Besides being wearable technology, it’s also meant to be an interactive art piece.
For this, his third version, the TV is a 1960’s RCA Victor Portable Television. You can see some of the TVs he found for previous versions on his hackaday.io page. They’re all truly vintage. He gutted this latest one and attached WS2812 LED strips in a serpentine pattern inside the screen. The LEDs are controlled by his code and the FastLED library running on an ESP8266. Power comes from four NiMH AA-format batteries, giving him 5 V, which he regulates down to 3.3 V. His phone serves as a WiFi hotspot.
[Nate] limits the commands so that only positive things can be displayed, a heart for example. Or you can tweak what’s being displayed by changing the brightness or make the LEDs twinkle. Judging by the crowds we see him attracting in the first video below, we’d say his project was a huge success. In the second video, Nate does a code walkthrough and talks about some of his design decisions.
With little more than pen, paper, dice, and imagination, a group of friends can transport themselves to another plane for shenanigans involving dungeons and/or dragons. An avid fan of D&D and a budding woodworker, Imgurian [CapnJackHarkness] decided to build gaming table with an inlaid TV for their inaugural project.
The tabletop is a 4’x4′ sheet of plywood, reinforced from underneath and cut out to accommodate a support box for the TV. Each leg ended up being four pieces of 1’x4′ wood, laminated together with a channel cut into one for the table’s power cable. An outer ledge has dice trays — if they’re even needed in today’s world — ready for all those nat 20s, cupholders because nobody likes crying over spilled drinks, and electrical outlets to keep devices charged. Foam squares cover the tabletop which can be easily removed and washed if needed — but more on that in a second. [CapnJackHarkness] painted the table as the wood rebuffed many attempts at staining, but they’re happy with how it turned out.
[LittleTern] — annoyed by repetitive advertisements — wanted the ability to mute their Satellite Box for the duration of every commercial break. Attempts to crack their Satellite Box’s IR protocol went nowhere, so they thought — why not simply mute the TV?
Briefly toying with the idea of a separate remote for the function, [LittleTern] discarded that option as quickly as one tends to lose an additional remote. Instead, they’re using the spare RGYB buttons on their Sony Bravia remote — cutting down on total remotes while still controlling the IR muting system. Each of the four coloured buttons normally don’t do much, so they’re set do different mute length timers — customized for the channel or time of day. The system that sends the code to the TV is an Arduino Pro Mini controlling an IR LED and receiver, with a status LED set to glow according to which button was pressed.
What is it about remote controls? They’re like some vortex of household chaos, burrowing into couch cushions while accusations fly about who used it last. Or they land in just the right spot on the floor to be stepped on during a trip to the bathroom. And don’t get us started about the fragility of their battery case covers; it’s a rare remote in a house with kids whose batteries aren’t held in by strips of packing tape.
But [Alex Rich]’s Bose radio remote discovered another failure mode: imitating a dog chew toy. Rather than fork out $90 for a replacement, [Alex] undertook a 3D-printed case to repair the chewed remote. He put an impressive amount of reverse engineering into the replacement case, probably expending much more than $90 worth of effort. But it’s the principle of the thing, plus he wanted to support some special modifications to the stock remote. One was a hardware power switch to disconnect the batteries entirely, hidden in the bottom shell of the case. The second was the addition of a link to his thermostat to adjust the volume automatically when the AC comes on. That required a Trinket inside the remote and a few mods to make room for it.
When you acquired your first oscilloscope, what were the first waveforms you had a look at with it? The calibration output, and maybe your signal generator. Then if you are like me, you probably went hunting round your bench to find a more interesting waveform or two. In my case that led me to a TV tuner and IF strip, and my first glimpse of a video signal.
An analogue video signal may be something that is a little less ubiquitous in these days of LCD screens and HDMI connectors, but it remains a fascinating subject and one whose intricacies are still worthwhile knowing. Perhaps your desktop computer no longer drives a composite monitor, but a video signal is still a handy way to add a display to many low-powered microcontroller boards. When you see Arduinos and ESP8266s producing colour composite video on hardware never intended for the purpose you may begin to understand why an in-depth knowledge of a video waveform can be useful to have.
The purpose of a video signal is to both convey the picture information in the form of luminiance and chrominance (light & dark, and colour), and all the information required to keep the display in complete synchronisation with the source. It must do this with accurate and consistent timing, and because it is a technology with roots in the early 20th century all the information it contains must be retrievable with the consumer electronic components of that time.
We’ll now take a look at the waveform and in particular its timing in detail, and try to convey some of its ways. You will be aware that there are different TV systems such as PAL and NTSC which each have their own tightly-defined timings, however for most of this article we will be treating all systems as more-or-less identical because they work in a sufficiently similar manner.
If you’re old enough to remember Cathode Ray Tube (CRT) Televisions, you probably remember that Sony sold the top products. Their Trinitron tubes always made the best TVs and Computer Monitors. [Alec Watson] dives into the history of the Sony Trinitron tube.
Sony Color TVs didn’t start with Trinitron — for several years, Sony sold Chromatron tubes. Chromatron tubes used individually charged wires placed just behind the phosphor screen. The tubes worked, but they were expensive and didn’t offer any advantage over common shadow mask tubes. It was clear the company had to innovate, and thanks to some creative engineering, the Trinitron was born.
All color TV’s shoot three electron guns at a phosphor screen. Typical color TVs use a shadow mask — a metal sheet with tiny holes cut out. The holes ensure that the electron guns hit only the red, green and blue dots of phosphor. Trinitrons use vertical bars of single phosphor color and a picket fence like aperture grille. The aperture grill blocks less of the electron beam than a shadow mask, which results in a much brighter image. Trinitrons also use a single electron gun, with three separate cathodes.
[Alec] is doing some amazing work describing early TV systems and retro consumer electronics over on his YouTube channel, Technology Connections. We’ve added him to our Must watch subscription list.
Television has been around for a long time, but what we point to and call a TV these days is a completely different object from what consumers first fell in love with. This video of RCA factory tours from the 1950s drives home how foreign the old designs are to modern eyes.
Right from the start the apparent chaos of the circuitry is mindboggling, with some components on circuit boards but many being wired point-to-point. The narrator even makes comments on the “new technique for making electrical connections” that uses a wire wrapping gun. The claim is that this is cleaner, faster, and neater than soldering. ([Bil Herd] might agree.) Not all of the methods are lost in today’s manufacturing though. The hand-stuffing and wave soldering of PCBs is still used on lower-cost goods, and frequently with power supplies (at least the ones where space isn’t at a premium).
It’s no surprise when talking about 60+ year-old-designs that these were tube televisions. But this goes beyond the Cathode Ray Tube (CRT) that generates the picture. They are using vacuum tubes, and a good portion of the video delves into the manufacture and testing of them. You’ll get a glimpse of this at 3:20, but what you really want to see is the automated testing machine at 4:30. Each tube travels along a specialized conveyor where the testing goes so far as to give a few automated whacks from corks on the ends of actuators. As the tube gauntlet progresses, we see the “aging” process (around 6:00) when each tube is run at 3-4 times the rated filament voltages. Wild!
There’s a segment detailing the manufacture of the CRT tubes as well, although these color tubes don’t seem to be for the model of TV being followed during the rest of the films. At about 7:07 they call them “Color Kinescopes”, an early name for RCA’s CRT technology.
During the factory tours we get the overwhelming feeling that this manufacturing is more related to automotive than modern electronic. These were the days when televisions (and radios) were more like pieces of furniture, and seeing the hulking chassis transported by hanging conveyors is just one part of it. The enclosure plant is churning out legions of identical wooden consoles. This begins at 11:55 and the automation shown is very similar to what we’d expect to see today. It seems woodworking efficiency was already a solved problem in the ’50s.