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This Instructables will teach you how to make a programmable pitch sequencer for any cassette tape machine, using Pulse Width Modulation (PWM) from a Raspberry Pi Pico. By the end of the project you will be able to add pitch and volume automation to your tape loops, using a custom OLED interface and a single rotary controller.

If you have been wanting to add a pitch mod to your tape machine but haven’t been sure how, or if you’re looking to upgrade your existing pitch mod, this tutorial will guide you through the process from start to finish, including some background theory, and links to scripts and resources.


Raspberry Pi Pico ~ £3
Rotary Encoder KY-040 ~ £1.5
OLED SSD-1306 ~ £4
2N7000 N-Channel MOSFET ~ £1

Micropython Code Available Here


If you want to add a volume gate you will need:
LED (doesn’t matter what colour/size)
Heatshrink or Electrical Tape

If you want to make a case:

Any material you like!

You could look at making a 3D printed case, or even look at ways of mounting the circuit into the tape machine. If you end up making it an external module, then I suggest using 3.5mm jack cables to connect between the module and the tape machine.

You will also want:

Wire/Jumper cables
Soldering Iron”

Link to article