Making A Tape Echo The Traditional Way

September 14, 2022 by Dave Walker 12 Comments

[Juan Nicola] has taken inspiration from the musician hackers of old and re-purposed a reel-to-reel tape recorder into a tape-echo for his guitar with a built-in valve amplifier (video in Spanish).

The principle is to record the sound of the guitar onto a piece of moving magnetic tape, then to read it back again a short time later. This signal is mixed with the live input and re-recorded back onto the tape further back. The effect is heard as an echo, and this approach was very popular before digital effects became readily available.

[Juan] installed a new read-head onto his Grundig TK40 and managed to find a suitable mechanical arrangement to keep it all in place. He has since updated the project by moving to a tape loop, allowing an infinite play-time by re-using the same piece of tape over and over.

Turning tape machines into echo effects is not a new idea, and we’ve shown a few of them over the years, but every one is slightly different!

Both versions are shown after the break. YouTube closed-caption auto-translate might come in handy here for non-Spanish speakers.

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Neon Lamps — Not Just For Pilot Lights

September 13, 2022 by Dan Maloney 30 Comments

It’s easy to see why LEDs largely won out over neon bulbs for pilot light applications. But for all the practical utility of LEDs, they’re found largely lacking in at least one regard over their older indicator cousins: charm. Where LEDs are cold and flat, the gentle orange glow of a neon lamp brings a lot to the aesthetics party, especially in retro builds.

But looks aren’t the only thing these tiny glow lamps have going for them, and [David Lovett] shows off some of the surprising alternate uses for neon lamps in his new video. He starts with an exploration of the venerable NE-2 bulb, which has been around forever, detailing some of its interesting electrical properties, like the difference between the voltage needed to start the neon discharge and the voltage needed to maintain it. He also shows off some cool neon lamp tricks, like using them for all sorts of multi-vibrator circuits without anything but a few resistors and capacitors added in. The real fun begins when he breaks out the MTX90 tube, which is essentially a cold cathode thyratron. The addition of a simple control grid makes for some interesting circuits, like single-tube multi-vibrators.

The upshot of all these experiments is pretty clear to anyone who’s been following [David]’s channel, which is chock full of non-conventional uses for vacuum tubes. His efforts to build a “hollow state” computer would be greatly aided by neon lamp circuits such as these — not to mention how cool they’d make everything look.

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This Vintage Alphanumeric Display Was Huge, Hot, Heavy, And Expensive

September 4, 2022 by Donald Papp 20 Comments

It’s easy to take display technology for granted nowadays, but the ability to display data in a human-readable way was not always easy. This is demonstrated well by the Pinlite 30003 Alphanumeric Display Module, a four-character display that was pure luxury for its time.

Each display is a rectangular vacuum tube containing 17 incandescent light filaments.

Not only were the 17 segments that make up each display capable of showing any letter or number, but they were even daylight-readable! Each of those 17 segments is an incandescent lamp filament, which is how the required brightness was achieved. The sturdy module shown here holds four such displays, each of which is on its own pluggable board with a dedicated character decoder chip directly behind it.

As [AnubisTTL] points out, the resulting unit is bulky, has terrible character spacing, and was no doubt very costly. By today’s standards, it is almost unimaginably heavy, hot, and impractical. But before high-brightness LEDs were a thing, a daylight-readable alphanumeric character display was really something special. It would absolutely have been worth the money and effort to the right people.

Before small and efficient displays were commonplace, the solution to the problem of how to display data efficiently and in an easy-to-read format took a lot of really unusual (and clever) turns as engineers worked around the limitations of the time. This resulted in oddities like the SD-11 Sphericular Display, which is mostly empty space on the inside. Another great example is the Eidophor, a projector from before projectors were even a thing.

Knight Rider Keeps On Truckin’

August 21, 2022 by Adam Fabio 39 Comments

[AJ] and [Joe], collectively the [Knight Rider Historians] are bringing back one of the most iconic vehicles of the 1980’s. Everyone remembers KITT driving into the F.L.A.G. truck. Even the Mythbusters re-enacted the stunt back in 2007. The duo managed to track down the original tractor and trailer from the show for restoration, and part of that process means uncovering the Hollywood hacks used to make the car-driving-into-trailer stunt work.

Back in the ’80s when a movie or TV show wrapped up, the props were often re-used in other productions or sold off. The 1975 Dorsey trailer used on Knight Rider was eventually purchased, stripped down, and painted white. It spent the last 30 years serving as a racing trailer. Carrying cars, and tools, and serving as a mobile shop at the track.

Unsurprisingly, most of the custom parts from Knight Rider are gone – but some hints remain. Specifically, [KRH] are trying to figure out how the drive-up door operated. Originally they assumed it was a hydraulic ram system that pulled the cables. However, above a dropped ceiling they found a welded hard mount and a 24-foot rail running down the trailer roof.

They believe the hard mount was for a winch, and the rail was used as a cable guide for two winch cables. A set of pulleys just behind the door directed these cables down to the ramp itself.

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A Particularly Polished ATX Bench Power Supply

August 18, 2022 by Tom Nardi 43 Comments

Let’s be real, yanking the ATX power supply out of an old desktop computer and turning it into something you can use on the workbench isn’t exactly an advanced project. In fact, you could probably argue it’s one of the first DIY builds a budding electronic hobbyist should tackle — after all, you’re going to need a reliable bench supply if you want to do any serious work anyway.

But of course, there’s a big difference between doing the minimum and really giving something your all, and we think this ATX bench supply from [Steve Thone] of The Neverending Projects List is a phenomenal example of the latter. It not only looks impressive, but it’s been tricked out with plenty of bells and whistles to make it as capable as possible. What was once a basic 230 watt PSU pulled from an old Dell is now a piece of gear that any hacker or maker would love to have in their collection. Continue reading “A Particularly Polished ATX Bench Power Supply” →

RollBack Breaks Into Your Car

August 17, 2022 by Elliot Williams 68 Comments

Rolling codes change the signal sent by car keyfobs unpredictably on every use, rendering them safe from replay attacks, and we can all sleep well at night. A research team lead by [Levente Csikor] gave a presentation at Black Hat where they disclose that the situation is not pretty at all (PDF).

You might know [Samy Kamkar]’s RollJam attack, which basically consists of jamming the transmission between fob and car while the owner walks away, fooling the owner into clicking again, and then using one of the two rolling codes to lock up the car, keeping the other in your back pocket to steal it once they’re getting coffee. This is like that, but much, much worse. Continue reading “RollBack Breaks Into Your Car” →

Back To The Future Prop Can Tell When It Hits 88 MPH

August 17, 2022 by Tom Nardi 8 Comments

Obviously, the most iconic piece of fictional hardware from the Back to the Future films is Doc Brown’s DeLorean DMC-12 time machine. But we’d have to agree with [Jason Altice] of CodeMakesItGo that the second-most memorable gadget is the modified Futaba remote control used to control the DeLorean from a distance. Now, thanks to his detailed build guide, you can build your own version of the time machine’s controller — complete with working speed readout.

Now to be clear, [Jason] isn’t claiming that his build is particularly screen accurate. It turns out that the actual transmitter used for the prop in the film, the Futaba PCM FP-T8SGA-P, has become difficult to find and expensive. But he argues that to the casual observer, most vintage Futaba transmitters are a close enough match visually. The more important part is recreating the extra gear Doc Brown bolted onto his version. Continue reading “Back To The Future Prop Can Tell When It Hits 88 MPH” →