Building A Cassette Deck Controller To Save A Locked Out Car Stereo

July 9, 2024 by Lewin Day 27 Comments

Cars have had DRM-like measures for longer than you might think. Go back to the 1990s, and coded cassette decks were a common way to stop thieves being able to use stolen stereos. Sadly, they became useless if you ever lost the code. [Simon] had found a deck in great condition that was locked out, so he set about building his own controller for it.

The build relies on the cassette transport of a car stereo and a VFD display, but everything else was laced together by Simon. It’s a play-only setup, with no record, seeing as its based on an automotive unit. [Simon]’s write up explains how he reverse engineered the transport, figuring out how the motors and position sensors worked to control the playback of a cassette.

[Simon] used an Atmega microcontroller as the brains of the operation, which reads the buttons of the original deck via an ADC pin to save I/O for other tasks. The chip also drives the VFD display for user feedback, and handles auto reverse too. The latter is thanks to the transport’s inbuilt light barriers, which detect the tape’s current status. On the audio side, [Simon] whipped up his own head amplifier to process the signal from the tape head itself.

Fundamentally, it’s a basic build, but it does work. We’ve seen other DIY tape decks before, too. There’s something about this format that simply refuses to die. The fans just won’t let Compact Cassette go down without a fight. Video after the break.

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Build Your Own Tape Recorder/Player

June 21, 2024 by Al Williams 14 Comments

If you want to read something from magnetic tape, you need a tape head, right? Or you could do like [Igor Brichkov] and make your own. It looks surprisingly simple. He used a washer with a small slot cut in it and a coil of wire.

The first experiment, in the first video below, is using a commercial tape head connected to a preamp. Music playing “through” the homemade head is readable by the commercial tape reader. This is a prelude to creating an entire tape deck using the head, which you can see in the second video below.

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Building A Tape Echo In A Coke Can Tape Player That Doesn’t Really Work

April 15, 2024 by Lewin Day 6 Comments

Back in the 1990s, you could get a tape player shaped like a can of Coca Cola. [Simon the Magpie] scored one of these decks and decided to turn it into a tape echo effect instead. It didn’t work so well, but the concept is a compelling one. You can see the result in the video below.

The core of the effect is a tape loop, which [Simon] set up to loop around a pair of hacked-up cassette shells. This allows him to place one half of the loop in the Coca-Cola cassette player and the other half in a more conventional desktop tape deck. A 3D-printed bracket allows the two decks and the tape loop to be assembled into one complete unit.

The function is simple. The desktop tape deck records onto the loop, with the Coca-Cola unit then playing back that section of tape a short while later. Hey, presto — it’s a tape delay! It’s super lo-fi, though, and the tape loop is incredibly fragile.

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2023 Cyberdeck Challenge: CyberTapeDeck

August 23, 2023 by Tom Nardi 9 Comments

There seem to be two schools of thought when it comes to picking an enclosure for your cyberdeck project: you either repurpose the carcass of some commercially produced gadget, or you build a new case yourself. The former can lead to some very impressive results, especially if your donor device is suitably vintage, but the latter is far more flexible as the design will be based on your specific parameters.

But for the CyberTapeDeck, [Matthew] decided to take a hybrid approach. The final product certainly looks like it’s built into a 1980s portable tape deck, but on closer inspection, you’ll note that the whole thing is actually 3D printed. The replica doesn’t just nail the aesthetics — it also includes the features you’d expect from the real thing, including an extendable handle and functional buttons which the internal Raspberry Pi 3 sees as a macropad thanks to an Arduino Pro Micro.

A seven inch LCD stands in for the tape door, and while it unfortunately doesn’t look like [Matthew] was able to replicate the opening mechanism to angle the display, you can at least stand the whole thing on its end to provide a more comfortable viewing experience.

[Matthew] says one of the intended purposes for this cyberdeck is to get his son excited about working with electronics and programming, so in a particularly nice touch, he’s mounted a terminal block over the “speaker” that ties into the Pi’s GPIO pins. This provides a convenient interface for experimenting on the go, without getting tangled up in exposed wiring.

We appreciate that [Matthew] has released the STL files for all of the printed parts, because even though it makes a great cyberdeck, the design is begging to house a faux-retro media player.

Simple Universal Modem Helps Save And Load Data From Tape

July 27, 2022 by Lewin Day 22 Comments

Back in the early days of the home computer revolution, data was commonly saved on tape. Even better, those tapes would make an almighty racket if you played them on a stereo, because the data was stored in an audio format. The Simple Universal Modem from [Anders Nielsen] is built to work in a similar way, turning data into audio and vice versa.

The project consists of a circuit for modulating data into audio, and demodulating audio back into data. It’s “universal” because [Anders] has designed it to be as format-agnostic as possible. It doesn’t matter whether you want to store data on a digital voice recorder, a cassette deck, or an old reel-to-reel. This build should work fairly well on all of them!

On the modulation side of things, it’s designed to be as analog-friendly as possible. Rather than just spitting out rough square waves, it modulates them into nice smooth sine waves with fewer harmonics. On the demodulation side, it’s got an LM393 comparator which can read data on tape and spit out a clean square wave for easy decoding by digital circuitry.

If you find yourself trying to recover old data off tapes, or writing to them for a retrocomputing project, this build might be just what you need. [Anders] even goes as far as demonstrating its use with an old reel-to-reel deck in a helpful YouTube video.

There really were some weird ways of storing data way back when. Just ask IBM. Video after the break.

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Pitch Sequencer Turns Tascam Tape Deck Into Instrument

May 11, 2022 by Lewin Day 4 Comments

The cool thing about magnetic tape is that by varying the speed at which you play it back, you can vary the pitch of the output. [Issac] decided to take advantage of this, executing a fancy digitally-controlled pitch mod on his Tascam Porta 02 tape deck.

The build uses a Raspberry Pi Pico, which employs PWM to control the speed of the tape drive’s motor. This is achieved with the use of an NPN transistor driven by the PWM output of the Pico. This allows accurate control of motor speed, and thus pitch.

With that sorted out, the project was fleshed out with an OLED screen and a rotary encoder. These allow various patches or scripts to be run on the Pico, controlling the motor speed of the tape player in various ways. With a bit of work, [Issac] was also able to create a function that converted MIDI note values into PWM values that determine various motor speeds.

The natural thing to do next was to put in a tape with a looping sample at a set pitch, and then vary it in a sequence controlled by the Pico. The 8 steps of the sequence can be manually set with the rotary control, and in future, [Issac] even plans to add a real MIDI input, allowing the system to act as a monophonic synth.

If you prefer other routes to pitch shifting shenanigans, check out this project. Video after the break.

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Know Audio: Mixtapes, Tape Loops, And Razor Blades

December 20, 2021 by Jenny List 16 Comments

In our no-nonsense journey through the world of audio technology we’ve so far have looked at digital audio and the vinyl disk recording. What’s missing? Magnetic tape, the once-ubiquitous recording medium that first revolutionised the broadcast and recording industries in the mid-20th-century, and went on to be a mainstay of home audio before spawning the entire field of personal audio. Unless you’re an enthusiast or collector, it’s likely you won’t have a tape deck in your audio setup here in 2021 and you’ll probably be loading your 8-bit games from SD card rather than cassette, but surprisingly there are still plenty of audio cassettes released as novelties or ephemeral collectables.

The Device That Made The Sound Of The Latter Half Of The 20th Century

"Like a travelling razor blade", a Blattnerphone steel-strip tape recorder at the BBC in 1937. Douglas Hallam, Jr., Public domain. — “Like a travelling razor blade”, a Blattnerphone steel-strip tape recorder at the BBC in 1937. Douglas Hallam, Jr., Public domain.

The first magnetic recordings were made directly on metal wires, but metal fatigues as it bends. By coating a flexible plastic tape in ferrous particles, the same simple technique of laying down an audio signal as variations in the magnetic field could be made smaller, lighter, and more robust. But the key to the format’s runaway success is the technical advancements that differentiate those 1950s machines from their wire recorder ancestors.

Whether it is a humble cassette recorder or a top-end studio multitrack, all tape recorders are very similar. There are two reels that hold the tape: the playback reel that houses the recording, and the take-up reel that stores the tape as it plays in the machine. The take-up reel is lightly driven to run faster than the tape speed, and the playback reel has a slight braking force to keep the tape under tension at all times. Continue reading “Know Audio: Mixtapes, Tape Loops, And Razor Blades” →