Mike from SISKworks showed us the Modified Tape Player Prototype, a motor-controlled cassette instrument developed from his earlier "poor man's Mellotron" idea.
He explained that the original version uses one continuous tape loop with a constant tone. Five buttons trigger playback, and each button has a knob that tunes motor speed for a different pitch. The newer prototype keeps that five-key approach and adds a Daisy microprocessor for delay, reverb, filter, harmonizer and reverse grain effects.
The control knobs adjust the last effect engaged, and the filter can self-oscillate slightly. The unit also includes a step sequencer with normal, reverse, bounce and random directions. Steps can be switched on or off, and tempo, length, glide and swing are adjustable. A hold mode latches the last key for drone use.
The prototype includes gate, CV and clock inputs, and it is planned for 1V/oct tuning. It can use tape loops or full-length cassettes, but it does not record to tape. Pricing is not set, and the final version is likely to be desktop rather than Eurorack.
A lovely collection of hand made custom sound devices here:
https://www.siskworks.com/
https://www.etsy.com/shop/SISKworks