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2 layers94 × 46 mmSamplooler stack top, the printed circuit board in 3D

Samplooler stack top

willbearfruits/samplooler

A small looper you play by tilting it, and instruments for the same board: ESP32-S3 firmware, circuit boards, a browser flasher and a desktop app

Size
94 × 46 mm
Copper layers
2
Thickness
1.6 mm
Parts
12
Nets
9
Pads
67
Tracks, vias
73, 46
Pours
7
Routed
Yes
KiCad
KiCad 10.0 (file 20260206)
Created
25 Sep 2026
Updated
19 Oct 2026

Overview

Samplooler stack top is an open-source printed circuit board by willbearfruits, from the willbearfruits/samplooler repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 94 × 46 mm with 12 parts on 9 nets, routed with 73 tracks and 46 vias.

Its parts include 3 capacitors, 2 ICs and 1 connector. It belongs with the audio and music boards and the ESP32 boards of this library.

README

README.md

Samplooler

build

A small looper you play by tilting it. Hold the button and make a sound; let go and it loops. Tip the box forward and the loop runs faster, tip it back and it runs backwards, roll it sideways for a tape delay or a stutter.

The Samplooler screen: a tape between two reels with a stick-figure operator running on it, forwards, backwards, with delay echoes, stuttering, juggling grains and flung off its feet at 8x

PHOTO: the Stack in a hand, tipped forward, screen lit (media/photos/stack-hand.jpg)

Try it and flash it from the browser · Manual · Build one · Get one

The loop is a tape between two reels, and a small operator runs on it, as fast as you tip the box. The screen above is the firmware's own drawing code, run on a computer.

VIDEO: someone playing a Stack, filmed, with its sound, about 60 s

What it does

RecordHold the button and make a sound, up to 20 s at 32 kHz. Let go and it loops.
TiltForward plays faster, back plays backwards. Snap rounds the speed to octaves and fifths.
RollLeft adds a tape delay, right a stutter.
ModesTAPE (speed and pitch move together) and GRAIN (they move apart).
VoiceOptional: SING's 18 voices on the input before it records (autotune, harmonies, choir, vocoder, echo).
SpeakerCan be switched off, so only the line out plays, when the speaker feeds back into the mic.
Slots8 loops saved on the board, kept when you update it.
TogetherOver the radio with the other instruments: a take sets their tempo or lands on their beat; key and scale are shared.
With a computerUSB MIDI and a USB sound card on one cable, and a VST3 plugin that shows and sets everything.
Other instrumentsMore firmwares for the same box: a breakcore-to-doom machine, a singing Buddha with a wall of amps, a flute you blow.

Other instruments

The same Stack can be flashed with WRECK, MANTRA or HUFF, and flashed back. Install them from the page or with the desktop app in app/. More are in progress (instruments/, ROADMAP.md). Anyone can add one (CONTRIBUTING.md).

Get one

  • Buy one: built by hand in Haifa. Write and ask about price and shipping: Dogme84@gmail.com · WhatsApp.
  • Build it in the workshop: the ESP32 workshop, 7 meetings at MEZO, Haifa, 2,200 ₪, kit included.
  • Build it yourself: order the boards, solder the modules on, flash it: docs/BUILD.md.

Status

Early. The current Stack is rev C: it has been made and runs the firmware (screen, microphone, tilt, line out and USB MIDI/audio work). The board files here are rev D, which is being tested now (October 2026); rev C's files are at the git tag checkpoint/boards-rev-c. The three other instruments on the list have run on a board; eight more are in progress. What comes next is in ROADMAP.md. Reports of builds, good or bad, are welcome in the issues.

What is where

PathWhat
ROADMAP.mdwhat is done and what comes next
docs/the manual and the build guide
firmware/the Samplooler's ESP-IDF 5.5 project
instruments/the other instruments, each a complete ESP-IDF project
core/the code the instruments share
hardware/the Stack's schematics, boards and JLCPCB order files
plugin/the VST3 and standalone plugin (JUCE)
app/the desktop app: the library, one-click install of any instrument on a board, and the Samplooler back
media/pictures and screen grabs
site/the project page and the browser flasher
tools/flash.sh, sl_midi.py (log and MIDI from a shell), release.sh, library.py

Licence


Part of Serious S.H.I.T.: instruments, tools and workshops made in Haifa by Yaniv Schonfeld (Willbear). If Samplooler is useful to you, support it on Patreon.

Parts

12
QtyValueFootprintReferences
4M3MountingHole:MountingHole_3.2mm_M3_Pad_ViaH1, H2, H3, H4
2100nCapacitor_SMD:C_0805_2012MetricC2, C3
110uCapacitor_SMD:C_0805_2012MetricC1
1INMP441 (under)samplooler:INMP441_Round_UnderU2
1OLED 0.96in (under)samplooler:SSD1306_0.96in_I2C_UnderU1
1OLED pin 1Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm_NumberLabelsJP1
1OLED pin 2Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm_NumberLabelsJP2
1To bottom boardConnector_PinHeader_2.54mm:PinHeader_2x04_P2.54mm_VerticalJ1

Questions

How big is the Samplooler stack top PCB?

It measures 94 × 46 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Samplooler stack top use?

12 parts. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Samplooler stack top KiCad files?

From the willbearfruits/samplooler repository on GitHub, at the commit this page was made from: the board is hardware/stack-top/samplooler-stack-top.kicad_pcb and its schematic hardware/stack-bottom/samplooler-stack-bottom.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Samplooler stack top design in my own project?

Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

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