Transform Your Old Walkman Into a Musical Instrument
John Park's Adafruit guide presents two ways to make a cassette tape instrument.
In the 1980s, one might say that radio still ruled the personal listening space, but if you wanted to play a specific song or album on-the-go, a Walkman tape player was the thing to have. On certain units it was actually possible to vary the motor speed in order to modify how fast it played. which also meant modifying the pitch. John Park's hack, or pair of hacks, take advantage of variable speed playback to modify the sound of a pre-recorded sine wave tritone.
The first hack, the “Walkmellotron," wires a DAC up to the GE 3-5362A portable cassette player/recorder’s speed potentiometer interface. The DAC is controlled by a QT Py RP2040 dev board, which can be hooked up to any MIDI device as a user interface. As shown in the video below, the effect is quite eerie. Without a bit of context – e.g. knowing that the keyboard is varying the tape speed – what's going on might not be immediately evident.
The second Walkman mod requires a bit more in the way of soldering and additional hardware, as it forgoes the tape player’s controls altogether. A QT Py RP2040 still provides processing power, but it uses a new motor, along with an L9110H H-bridge motor driver. This allows the tape to run at variable speeds, and even go backwards as needed, though you'll need to use a modified "loop tape" to avoid damage when it runs out.
The device is set up to be played manually via a potentiometer and 3D-printed crank. With a bit more work, it would seem possible to use it as a MIDI device as well.
