PO-33 K.O! for ESP32-S3
A pocket-sized sampler on a $5 dev board. AMY-powered, 16-step, 16 punch-in effects, 40 s of sampling. Flash from your browser — no toolchain required.
⚡ Flash from your browser
Plug in your ESP32-S3 dev board, click the button, and
ESP Web Tools
will do the rest. No esptool, no Python, no PlatformIO.
firmware.bin shipped on this site is a
placeholder. Build the firmware from source with
idf.py build and replace the placeholder files in
public/firmware/ before flashing for real.
See the docs page.
Features
Everything you need to make beats in a coffee cup.
Mono @44100 Hz × 16-bit,
PSRAM-backed, 16 slots split into 8 drum + 8 melodic voices.
16 patterns, 128-song chain mode, 2 parameter locks per step, chromatic pitch shifting on melodic slots.
Loop variants, unison, octave, stutter, scratch, reverse, retrigger, 6/8 quantize, filter sweep, bitcrush — and more.
Built on AMY — Juno-6, DX7, partial-breakpoint, and PCM sampler. All your synth voices live next to your samples.
ILI9341 240×320 SPI display with custom 2D draw API. Shows step position, pattern, BPM, slot, FX, and clock.
Or LiPo with deep-sleep wake-on-button. 5 min idle → 10 µA standby. PO-33 battery life, ESP32-S3 horsepower.
Quick start
- Wire up the dev board — DAC, mic, TFT, button matrix + modifier keys. See the hardware guide.
- Flash the firmware from this page, or build from source.
- Press REC + STEP 1 to record a sample into slot 1. Press REC again to stop.
- Press STEP N to add the recorded sample to step N. Press PLAY to start the sequencer.
-
Connect UART @ 115200 for the shell:
help,bpm 140,pattern 5,save.