
Samplooler panel stack
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

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
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.
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.

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
| Record | Hold the button and make a sound, up to 20 s at 32 kHz. Let go and it loops. |
| Tilt | Forward plays faster, back plays backwards. Snap rounds the speed to octaves and fifths. |
| Roll | Left adds a tape delay, right a stutter. |
| Modes | TAPE (speed and pitch move together) and GRAIN (they move apart). |
| Voice | Optional: SING's 18 voices on the input before it records (autotune, harmonies, choir, vocoder, echo). |
| Speaker | Can be switched off, so only the line out plays, when the speaker feeds back into the mic. |
| Slots | 8 loops saved on the board, kept when you update it. |
| Together | Over the radio with the other instruments: a take sets their tempo or lands on their beat; key and scale are shared. |
| With a computer | USB MIDI and a USB sound card on one cable, and a VST3 plugin that shows and sets everything. |
| Other instruments | More firmwares for the same box: a breakcore-to-doom machine, a singing Buddha with a wall of amps, a flute you blow. |
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).
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.
| Path | What |
|---|---|
| ROADMAP.md | what 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 |
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.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | M3 | MountingHole:MountingHole_3.2mm_M3_Pad_Via | H1, H2, H3, H4 |
| 2 | 100n | Capacitor_SMD:C_0805_2012Metric | C2, C3 |
| 1 | 10u | Capacitor_SMD:C_0805_2012Metric | C1 |
| 1 | INMP441 (under) | samplooler:INMP441_Round_Under | U2 |
| 1 | OLED 0.96in (under) | samplooler:SSD1306_0.96in_I2C_Under | U1 |
| 1 | OLED pin 1 | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm_NumberLabels | JP1 |
| 1 | OLED pin 2 | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm_NumberLabels | JP2 |
| 1 | To bottom board | Connector_PinHeader_2.54mm:PinHeader_2x04_P2.54mm_Vertical | J1 |
It measures 94 × 46 mm and has 2 copper layers, 1.6 mm thick.
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.
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.
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).

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

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

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