KLIPTOR screenshot 1

KLIPTOR

Shipped

Tremolo and filter pedal with an 8-step beat-locked filter sequencer, 3 gate shapes, and zero-latency operation.

CTO at Keystone Musical Instruments. Sole engineer and technical decision-maker.

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Tech Stack

MCU: STM32H750 (ARM Cortex-M7, 480MHz) via Daisy SeedMemory: 128KB Flash + 480KB SRAM + 64MB SDRAM + 8MB QSPI FlashAudio: 24-bit/96kHz stereo codec, DMA-managed buffersLanguages: C++, ARM assembly (VTOR/FPU setup)Build: GNU Make, ARM GCC toolchainLibraries: libDaisy, DaisySP, CMSIS-DSPI/O: 6 pots, 2 footswitches, 3 rotary switches, MIDI (5-pin DIN + USB), expression pedal, RGB LEDs

Stats

8
Sequencer steps
0.1Hz – 20Hz
Gate rate
3 (Square / Envelope / Ambient)
Gate shapes
128
Presets
20Hz – 20kHz
Filter sweep
9
MIDI CCs

Overview

A hardware tremolo and filter sequencer pedal built on the STM32H750 (ARM Cortex-M7, 480MHz) via Daisy Seed. Three gate shapes: Square for sharp cuts, Envelope for musical feel, and Ambient for pad-like S-curve swells with zero clicks. The step sequencer modulates filter frequency independently of gate rate, creating melodic filter patterns locked to quarter notes. 128 presets, expression pedal mapping via APEX mode, and configurable I/O modes (mono true bypass, mono-to-stereo, stereo buffered). 24-bit/96kHz stereo audio with custom QSPI bootloader for OTA firmware updates. Part of the Keystone Musical Instruments pedal line, launched January 2026.

Engineering Highlights

  1. 018-step beat-locked sequencer — Filter frequency modulation runs independently of gate rate, enabling complex rhythmic patterns with a simple interface.
  2. 02Zero-latency gating — Gate envelope applied directly in the audio callback with no lookahead buffer, preserving transient response.
  3. 03Cross-platform DSP core — Same C++ algorithm compiles for both STM32H750 firmware (ARM) and VST3 plugin (x86_64/ARM64) without modification.
  4. 04Custom QSPI bootloader — Firmware exceeds 128KB internal flash, boots from 8MB QSPI. OTA updates via USB MIDI SysEx.
  5. 05APEX expression pedal learning — Runtime parameter mapping without recompilation. Users assign expression pedal to any parameter with custom min/max/inversion, saved to flash.