Cassette players and tapes are fertile hacking ground. One reason is that their electromechanical and analog nature provides easy ways to fiddle with their operation. For example, slow down the motor and the playback speed changes accordingly. As long as the head is moving across the tape, sound will be produced. The hacking opportunities are nicely demonstrated by [Lara Grant]’s cassette player mod project.
The device piggybacks onto a battery-powered audio cassette player and provides a variety of ways to fiddle with the output, including adjustable echo and delay, and speed control. At the heart of the delay and echo functionality is the PT2399, a part from the late 90s capable of some pretty impressive audio effects (as long as a supporting network of resistors and capacitors are in place, anyway.)
[Lara] provides a schematic for the PT2399’s interface to the cassette player’s output, which is handy should anyone want to try a similar modification. Speed of playback is controlled by adjusting the cassette player’s motor with PWM. Volume control swaps a photocell in place of a rotary volume potentiometer, and additional audio jacks provide flexibility for mixing and matching input and output with other equipment.
You can see it in action in the video embedded below. Intrigued, and want a few more examples of modified tape players? How about a strange sort of cassette synth, or this unique take on a mellotron that uses a whopping 14 modified tape players under the hood? And really out there is the Magnetotron, which consists of a large rotating cylinder with tape loops stuck to it — the magnetic read head is mounted on a wand which the user manually moves across the tapes to create sounds.
Tape players are accessible, hackable things, so remember to drop us a line if you make something neat!
While packing merch for a recent gig, I realised I had the opportunity to do something a little fun. I’d released an album on tape, and spent a little extra to ensure the cassette itself was a thing of beauty. It deserved to be seen, rather than hidden away in a case on a shelf. I wanted to turn this piece of musical media into a necklace.
Of course, cassette tapes aren’t meant to be used in this way. Simply throwing a chain through the cassette would lead to tape reeling out everywhere. Thus, I fired up some CAD software and engineered a solution to do the job! Here’s how I built an adapter to turn any cassette tape into a cool necklace.
For [ke4mcl], this whole cassette craze of late is not a new discovery so much as it is a personal nostalgia machine. Since [ke4mcl] sees a lot of basic questions go unanswered, they made an incredible beginner’s guide to all things cassette deck. This concise wealth of information covers everything from terminology to operation, basic maintenance like repairing the belt and lubricating the motor, and appropriate cleaning methods for the various parts. Yep, we’re pretty sure this covers everything but the pencil winding technique, which you probably already knew about.
You don’t need a lot of tools and supplies to maintain a cassette deck or twelve (apparently they’re addictive) — mostly just head cleaning fluid, isopropyl, window cleaner, and a bunch of cotton swabs. And given this guide, you’ll enter the enclosure confidently, armed with knowledge about everything from the belts to the capstan to the head. This is valuable information, the kind of stuff your older brother wouldn’t take the time to explain to you in the 80s. But maybe he didn’t know reverse bias from the holes in the top of the tape.
Don’t care for the quality of audio cassettes? Tapes are good for lots of stuff, like data storage and decoration.
In the early 1980s cassette tapes were the standard storage medium for home computer users; readers of a certain age will remember fiddling with audio jacks, tape counters and signal levels, then waiting for several minutes while a program (hopefully) loaded correctly. While most people happily upgraded to much more reliable floppy disks, [Zack Nelson] decided to go back in time and add a suitably classic storage medium to a retrocomputing project, in the form of a cassette interface. The cassette player he had available was a Pearlcorder L400, which uses the smaller microcassette instead of the familiar audio tapes used in your Walkman or boombox.
[Zack] designed the entire thing from the ground up: first he decided to use differential Manchester encoding, which provides immunity against common disturbances like speed variations (which cause wow and flutter). The data is encoded in the frequency range from 1 kHz to 2 kHz, which suits the bandwidth of the cassette player. Next, he designed the interface between the computer and the tape recorder; built from an op-amp and a comparator with a handful of discrete components, it filters the incoming signal and clips it to provide a clean digital signal to be read out directly by the computer.
The system is demonstrated by hooking it up to an Arduino Nano, which reads out the data stream at about 3000 baud. The noise it makes should bring back memories to anyone brought up with the “PRESS PLAY ON TAPE” message; if it inspires you to make your own, we’re happy to report that full schematics and source code are available. [Zack] is not the first one to make his own cassette interface; we’ve seen a somewhat more complicated analog design before, as well as one based on an FPGA.
It has been a long time since we stored software and computer data on audiotape. But it used to be the de facto standard for hobby computers and [Noel] has a great video about the Amstrad’s system (embedded below) which was pretty typical and how the process could be sped up since today, you have perfect audio reproduction, especially compared to consumer-grade audiotape.
The cassette tapes suffered from several problems. The tape had an inherently low bandwidth, there was quite a bit of noise present from the analog circuitry and heads, and the transport speed wasn’t necessarily constant. However, you can easily digitally synthesize relatively noise-free sound at high fidelity and rock-solid frequency. So basically a microcontroller, like an Arduino, can look like an extremely high-quality tape drive.
My DEF CON Safe Mode badge just arrived in the mail this afternoon. The Vegas-based conference which normally hosts around 30,000 attendees every year has moved online in response to the global pandemic, and the virtual event spins up August 6-9. Known for creative badges, North America’s most well-known infosec con has a tick-tock cycle that alternates electronic and non-electronic badges from year to year. During this off-year, the badge is an obscure deprecated media: the audio cassette.
This choice harkens back to the DEF CON 23 badge which was an vinyl record — I have the same problem I did back in 2015… I lack access to playback this archaic medium. Luckily [Grifter] pointed everyone to a dump of the audio contents over at Internet Archive, although knowing how competitive the badge hacking for DEF CON is, I’m skeptical about the reliability of these files. Your best bet is to pull the dust cover off your ’88 Camry and let your own cassette roll in the tape deck. I also wonder if there are different versions of the tape.
But enough speculation, let’s look at what physically comes with the DEF CON 28 badge.
A lot of projects we feature use video in some form or other, but that video is invariably digital, it exists as a stream of numbers in a computer memory or storage, and is often compressed. For some of us who grew up working with composite video there is a slight regret that we rarely get up-close and personal with an analogue stream, so [Kris Slyka]’s project putting video on a conventional audio cassette is a rare opportunity.
Readers with long memories may recall the Fisher-Price PixelVision toy from the late 1980s which recorded black-and-white video on a conventional cassette running at many times normal speed. This system does not take that tack, instead it decreases resolution and frame rate to a point at which it can be recorded at conventional cassette speeds. The result is not particularly high quality, but with luminance on one side of a stereo recording and chrominance on the other it does work.
The video below the break is a run through the system, with an explanation of how video signals work. Meanwhile the code for both encoder and decoder are available through the magic of GitHub. If you’re interested further, take a look at our examination of a video waveform.