Send a Raspberry Pi Back in Time to 1980

One of our favorite hacker-scavengers on YouTube, [The Post-Apocalyptic Inventor], has been connecting his Raspberry Pi up to nearly every display that he’s got in his well-stocked junk pile. (Video embedded below.)

Modern monitors with an HDMI input connect right up to the Pi. Before HDMI came VGA, but the Pi doesn’t do that natively. One solution is to use a composite-to-VGA converter and pull the composite signal out of the audio jack. Lacking the right 4-pole audio cable, [TPAI] soldered some RCA plugs directly onto the Pi, and plugged that into the converter. On a yet-older monitor, he faced a SCART adapter. If you’re European, you’ll know these — it’s just composite video with a different connector. Good thing he had a composite video signal already on hand.

online-with-my-1980-tv-set-huc2ls56hwimkv-shot0004The pièce de resistance, though, was attaching the Pi to his 1980 Vega TV set. It only had an antenna-in connector, so he needed an RF modulator. With a (presumably) infinite supply of junk VCRs on hand, he pulled an upconverter out of the pile, and got the Pi working with the snazzy retro TV.

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Never Twice the Same Color: Why NTSC is so Weird

Ever wonder why analog TV in North America is so weird from a technical standpoint? [standupmaths] did, so he did a little poking into the history of the universally hated NTSC standard for color television and the result is not only an explanation for how American TV standards came to be, but also a lesson in how engineers sometimes have to make inelegant design compromises.

Before we get into a huge NTSC versus PAL fracas in the comments, as a resident of the US we’ll stipulate that our analog color television standards were lousy. But as [standupmaths] explores in some depth, there’s a method to the madness. His chief gripe centers around the National Television System Committee’s decision to use a frame rate of 29.97 fps rather than the more sensible (for the 60 Hz AC power grid) 30 fps. We’ll leave the details to the video below, but suffice it to say that like many design decisions, this one had to do with keeping multiple constituencies happy. Or at least equally miserable. In the end [standupmaths] makes it easy to see why the least worst decision was to derate the refresh speed slightly from 30 fps.

Given the constraints they were working with, that fact that NTSC works as well as it does is pretty impressive, and quite an epic hack. And apparently inspiring, too; we’ve seen quite a few analog TV posts here lately, like using an SDR to transit PAL signals or NTSC from a microcontroller.

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ESP8266 Transmits Television on Channel 3

We’ve seen a lot of ESP8266 projects in the past, but this one most definitely qualifies as a hack. [Cnlohr] noticed that the ESP8266, when overclocked, could operate the I2S port at around 80MHz and still not lose DMA data. He worked out how to create bit patterns that generate RF around 60MHz. Why is that interesting? Analog TVs can receive signals around that frequency on channel 3.

As you can see in the video below, the output is monochrome only and is a little snowy. It also will lose frames on some WiFi events, but this is all forgivable when you consider this very inexpensive module isn’t meant to do video output at all.

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Spectrum Analyzer on the Cheap

Provided you have an NTSC-compatible TV you can build yourself a really inexpensive spectrum analyzer. From there you just need one trivial piece of hardware to complete this build. [Bruce Land] has come up with a spectrum analyzer that shouldn’t cost any more than $5, if that’s what’s been keeping you from adding this tool to your workbench!

The spectrum analyzer is based on a PIC32 microcontroller which was previously proven in his Oscilloscope project. [Bruce] has managed to squeeze quite a bit out of this robust chip; the spectrum analyzer has 450 kHz bandwidth and runs a 256 Hz TV display and can output over 30 updates per second. The microcontroller runs the Fast Fourier Transform (FFT) to do calculations, with great results.

[Bruce] notes that the project was based on TV framework from another project, and that the FFT was added on top of that. Be sure to check out the source code on the project site if you’ve been on the hunt for an inexpensive spectrum analyzer, and if you need something with more processing power but only slightly more money, check out the FFT that runs on the Raspberry Pi’s GPU.

Build an analog TV station

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With the transition to digital TV, the FCC has abandoned the old analog format. Luckily, you can take advantage of this and set up your own analog TV station. The FCC has a tool on their site to see what channels are open in your area to broadcast in. To broadcast, you need a TV transmitter, but cheap short-range models can be found on eBay or made at home [pdf]. Once you have a transmitter, you can pump in a video source, either your own content or videos from youtube. One group, OMGimontv is showcasing popular youtube clips on channel 14 in New York. On their site, users can vote for what clips they want to see. Although this isn’t as simple as making a radio station, it still has a lot of potential.

[via BoingBoing]