🎛️ FM Drum panel art
coming soon

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Hold BOOTSEL on the module while connecting USB, then click Flash and pick the RP2 device.

Maddie MOD2

FM Drum

Drums · FM

A two-operator FM percussion voice — six parameters across two modes with smooth pickup switching.

Width
4 HP
Depth
28 mm
Power
+12V / −12V / +5V
MCU
Seeed XIAO RP2350
Controls
3 pots · button · LED
I/O
2 gate in · 1 CV in · PWM audio out

Overview

A two-operator FM percussion voice. The three pots double up across two modes for six parameters total — pitch, operator ratio, modulation index, decay, and ratio envelope. A “pickup” feature means parameters don’t jump when you switch modes, and all six are saved to flash. An accent input cuts the level by 6 dB.

Panel & I/O

Control Pin Mode 0 Mode 1
POT1 A0 Pitch Decay time
POT2 A1 Operator ratio Ratio envelope
POT3 / CV A2 Modulation index Modulation index
IN1 GPIO7 In — Trigger
IN2 GPIO0 In — Accent (−6 dB)
BUTTON GPIO6 Mode toggle & save
OUT GPIO1 Out — 10-bit PWM audio
LED GPIO5 Mode indicator

Features

  • Two-operator FM synthesis, wavetable-based
  • Six parameters via two pot modes
  • Pickup feature for jump-free mode switching
  • Parameters stored in onboard flash
  • Click-free cosine fade in/out

© 2026 Maddie Synths · firmware based on work by Hagiwo · original firmware CC0 1.0 · hardware design by Hagiwo