with a grain of granular.

For Simple Touch Board, Daisy Seed and MPR121 touch sensor.

About

Simple Touch Looper is an ongoing project. It is an unconventional looper Roey and I designed for the Simple Touch board. It’s not exactly a conventional looper à-la guitar pedal but rather an experimental instrument. Nevertheless it’s easily convertible in the classical looper with couple of small changes. Although at a first glance a looper might seem relatively simple kind of music gear, programming it revealed fair amount of challenges which in their turn inevitably led to some learnings, ideas and design decisions which I’d like to share below.

I’d be glad to hear your questions, suggestions, corrections on Synthux Academy Discord (thatvlad_).

Along the way we’ll learn how to:

• Work with DaisySeed’s SDRAM
• Read/write to audio buffer
• Modify playback speed and direction in different ways
• Prevent sonic artefacts when changing loop start during playback
• Start recording upon receiving input signal
• Reuse same knob to control different parameters and route parameter to different destinations
• Use programming concepts like classes, references, declaration and definition, dependency injection etc.

Overview

The instrument we’re talking about has three independent layers which are being fed from the shared audio buffer of sixty seconds length so from a single piece of audio recording it can produce three layers of loops played with different parameters.

Record and monitor

To begin the recording you need to tap pad R. If there’s no input signal or it’s below the threshold, the built in LED is going to blink signifying stand-by mode. Default threshold is -45dB. It can be changed by holding “TO” in “TOuch” (marked as Mod on the diagram) and adjusting the left fader. Once there’s signal exceeding the threshold the recording starts and LED lit constantly.