- Sequencer lanes 16
- Maximum pattern length 256 steps
- 16×16 layout 16 steps × 16 pages
- 32×16 layout 32 steps × 8 pages
- Pattern slots 999 + session recovery
- Sample kits 999 numbered folders + scratch kit 0
- Song mode 64-slot page chain
- Voice mode Per-voice pattern length
- FIRE Playhead sparks (ETC menu)
- Trigger probability 0%, 25%, 50%, 75% or 100%
- Trigger conditions Supported
- Performance controls Mute, solo and transpose
- Live saving Patterns and sample packs without stopping playback
- Sample browser MicroSD folders with live preview
TŒRN
by warft_labs
ABOUT
Hi, I'm Jan aka warft_labs - a musician and maker based in Hamburg. TŒRN started as a personal itch: I wanted a sequencer and sampler that feels like an instrument first, and a computer last - less buttons, less screen, less cables and less studio-feeling. Over the last years I’ve been prototyping, breaking, rebuilding, and testing it until it became something I genuinely love to play.
TŒRN is small-batch and still evolving. If you jump in now, you're joining early: you’ll find a few rough edges, but also a project with heart, openness, and lots of room to grow. If you like building, tweaking, or adding features, I’d love your help - feel free to contribute.
TŒRN is a standalone, open-source live performance sequencer - ready to operate on battery. Built to be played in motion - not prepared in advance.
It’s also a creative platform for your own ideas. The PCB brings sound, MIDI, light, touch, storage, and control together on one board, giving you a head start on fast prototypes. Build an interactive art installation, a theater cue player, a backing-track player, a fruit-touch instrument, or your own MIDI and lighting controller.
Tinker, build, and make it yours. Add sensors, switches, and faders; connect compatible I²C devices or another Arduino or microcontroller. Write your own behavior, build your own enclosure, and turn everyday objects into interfaces. The connector docs and source files are there to help you get started.
No laptop. No DAW. No preparation freeze. Build patterns. Break them. Save them. Keep playing. Everything happens while the clock is running. Patterns and sounds evolve inside the performance, not before it.
Start with the first beat guide, or explore the simulator. Its controls illustrate the workflow; browser sound and timing are approximate.
Key Features
A groovebox.
A starting point
for something else.
TŒRN is a groovebox, but it can be so much more than an instrument. Its Teensy 4.1 runs at 816 MHz in the current firmware build, with JST expansion headers exposing 17 GPIO pins and easy access to onboard 3.3 V and 5 V power.
Make it the heart of an interactive installation, a companion in your live setup, or an instrument nobody has imagined yet. Your project. Your code. Your way.
What will you make?
Sound, MIDI, light, touch, storage, and control on one board. Start with the instrument, or use the PCB as the foundation for your own project.
The PCB already has the building blocks you might need.
Less time assembling the basics.
More time making your idea work.
On stage.
In a gallery.
On your kitchen table.
One platform, many possible projects. Bring your own idea, add the interfaces it needs, and make the firmware your own.
Built with open-source, Arduino-compatible libraries and familiar tools. No reverse engineering or firmware hacking needed—start with the source, use the libraries you already know, and build from there.
A cue for the next scene. A sculpture that reacts to visitors. An instrument made from fruit. Choose a starting point below to explore what you could build.
Your next performance.
Build a band backing-track player, a theater cue system, or a portable sound-effects box. Record MIDI ideas and keep instruments moving together with MIDI clock.
Add a sensor.
Move a fader.
IF YOU CAN THINK IT, YOU CAN ADD IT.
Connect sensors, switches, faders, and compatible I²C devices. Add another Arduino or microcontroller. Write your own behavior, build a different enclosure, or turn an everyday object into an interface.
Tinker-friendly. DIY-friendly.
A head start for your next prototype.
Specifications
- Sample voices 8
- File format WAV
- Sample rate 44.1 kHz
- Bit depth 16-bit
- Channels Mono
- Maximum sample length 12 seconds per voice
- Editing Trim, reverse and TIME stretch
- Level control Per sample voice
- Per-voice processing ADSR, multimode filter, bitcrusher and WSOLA time-stretch
- TIME (stretch) Independent of pitch; 11 = off, ± about 10%
- Polyphonic engines 1
- Polyphony 3 voices
- Oscillators per polyphonic voice 3
- Monophonic engines 2
- Oscillators per monophonic engine 2
- Waveforms Sine, saw, square and triangle
- Polyphonic controls ADSR, filter envelope, waveform and pan
- Polyphonic tuning Cents and semitones
- Polyphonic presets Bass, Keys, Chiptune, Pad, Wow, Organ, Flute, Lead, Arp and Brass
- Mono LFO controls Rate, depth and filter modulation
- Mono arpeggiator controls Step and span per synth
- Mono reverb send None
- Envelope ADSR per voice
- Filter Low-pass, high-pass and band-pass with resonance
- Bitcrusher Adjustable bit depth and sample rate
- Reverb controls Room, damping and send
- Reverb sources Sample voices 1, 2, 4 and 6 to 8, plus the polyphonic synth
- Real-time editing Available while the sequence is running
- Recording destinations 8 sample voices
- Maximum recording length 12 seconds per voice
- Sources Built-in microphone, external microphone and line input
- Recording modes Hold-to-record and one-shot
- Monitoring Live input monitoring
- Level controls Input and output
- Recording during playback Supported
- Post-recording workflow Recordings can be sequenced immediately
- MIDI connectors 3.5 mm TRS Type A input and output
- MIDI transmission Notes, clock or both
- Clock sources Internal BPM or external MIDI
- Analog PPQN output 5 V pulse (J25), 1–32 PPQN
- Analog clock in 3–5 V pulse (J26, rev H+)
- Sidechain / gate out 5 V logic (J27, rev H+)
- CV Not provided (digital pulse / gate only)
- Clock routing PPQN output follows the active internal or external clock
- USB-C Power, USB audio output and serial data
- Codec SGTL5000
- Audio output 6.35 mm line out
- Headphone output 6.35 mm
- Microphone input 6.35 mm
- Line input 6.35 mm
- Built-in microphone Yes
- Controller Teensy 4.1
- Firmware environment Arduino
- Firmware license MIT
- Hardware design license CC BY-NC
- External RAM 16 MB
- Storage MicroSD, up to 64 GB
- Expansion connections JST
- Available rails 3.3 V, 5 V and ground
- Color schemes User-editable
- Clock / gate headers (rev H+) CLK-IN, CLK-OUT 5V, SIDEC-5V
- Expansion uses WS2812 lighting, additional inputs, switches, triggers, clocks and gates
No laptop. No freeze.
Standalone. Battery ready. Built to move. Extendable and accessible. Add what you need - use it your way.
HARDWARE
Fully assembled custom made PCB including SGTL5000 Audio IC, BQ24075 charging unit, PAM8403 amplifier and additional integrated support circuitry for TŒRN operation. This is the heart of TŒRN.
If you want to make your own: all files on GitHub → INCLUDED
The current firmware runs the Teensy 4.1 ARM Cortex-M7 at 816 MHz. It handles the audio engine, sequencing, MIDI and controls, with floating-point and DSP support.
PJRC Teensy 4.1 → ca. €45 INCLUDED
Two 8 MB PSRAM chips provide 16 MB of external working memory for sample buffers, effects and live processing. Samples and saved patterns are stored on the microSD card.
PSRAM module details → ca. €5 (with Teensy) INCLUDED
The standard build uses one 32×16 addressable RGB LED panel (512 LEDs). A smaller 16×16 build remains optional. Standard panel source →
Record and monitor line-level audio. 6.35mm (¼") stereo TRS jacks carry separate left and right channels. The current sampler records the left line-input channel as a mono WAV. Line out follows the selected 2-channel output routing.
INCLUDED
Sync and control synths, drum machines, and DAWs. Separate TRS MIDI Type A input and output ports support clock, notes, or both so you can drive external gear or be driven by a sequencer.
INCLUDED
Rigid enclosure and front panel in laser-cut smoke black acrylic. Easy to customize or re-cut from open-source files so you can tweak layout, add holes, or match your setup.
Housing DXFs and assembly files → INCLUDED
Parameter control, navigation, and visual feedback. Four DuPPa I2C Encoder V2.1 modules with illuminated RGB rotary-push encoders provide turning, push-to-select and visual feedback.
I2C rotary encoder devices → ca. 4x12€ INCLUDED
Sample storage and project data. The onboard microSD slot stores WAV samples, kits and patterns on a removable card. A microSD card is included with the unit. Use 32 GB FAT32 or 64 GB exFAT.
INCLUDED
Quick sampling from onboard mic or external mic/instrument via 6.35mm jack. Dual input lets you grab sounds on the fly without plugging in, or use a proper mic or line when you need it.
INCLUDED
Headphone monitoring on a 6.35 mm jack. The main mix is mono, so both ears hear the same signal. 2-channel mode can send voices 1–4 to the left and 5–8 to the right.
INCLUDED
Charging, firmware updates, USB audio output and serial access for the SD tool. Connect USB-C with a data cable and select TŒRN’s USB audio input in your DAW to record two channels. USB audio follows the same ETC → ADV → 2-CH routing as the headphone and line outputs. Use the separate TRS ports for musical MIDI. USB MIDI and USB host operation are not implemented on this connector in the current firmware.
INCLUDEDThe carrier includes a PAM8403 speaker amplifier. For a DIY build, solder a suitable 4 or 8 Ω speaker to a JST-PH 2.00 mm 2-pin mating lead and connect it to J10. Both leads are amplifier outputs; neither connects to ground. Switch the speaker on or off in VOL → SPKR.
Power TŒRN over USB-C or add a compatible single-cell LiPo for portable use. The carrier includes a BQ24075 charging circuit and power switch. Purchase the battery separately and check its connector polarity and enclosure fit before connecting it.
Five capacitive touch buttons provide single, menu, record, current-voice audition and FN shortcuts. Touch 4 + touch 5 requests a live fill during playback. Their actions also adapt to the active screen.
INCLUDED
Expandability for LEDs, triggers, clocks, gates, or custom hardware. JST connectors bring out 5 V, 3.3 V, GND, and free I/O — and on rev H+, dedicated CLK-IN (3–5 V), CLK-OUT (5 V) and SIDEC-5V headers — so you can add modules without soldering.
INCLUDEDBuild it yourself
Build a personal rev H unit from the open hardware files. Fit a Teensy, four DuPPa encoders, the matrix and a case. A finished TŒRN ordered from the shop arrives ready to play.
01 Fabricate the PCB yourself
Only if you did not buy the pre-assembled circuit board (PCB only) beside this step. That board is populated and nothing else: you still add the Teensy, encoders and the rest.
Order the 4-layer, 1.6 mm rev H PCB with the matching Gerbers, production BOM and CPL from the production package. Check every component match in the assembly quote before paying.
Pre-order or arrange sourcing for SGTL5000XNBA3 (C5196742), SJ1-3533 (C4991776), EG2219 (C3664594), EEE-FK1C102SV (C5686929), DM3BT-DSF-PEJS (C597972) and TLP2361 (C107626) before PCB assembly. The pre-order BOM gives quantities and sourcing routes. Use JLCPCB Parts Pre-order or an approved sourcing route, and verify the component matches in your quote.
JLCPCB assembles the carrier components, including the pogo pins, audio/MIDI jacks, encoder sockets, JST-PH headers, switch and microphone. CN1/CN2 pogo pins are included in the production BOM: C5157282, quantity 2. The BOM directory separates the assembled carrier parts from the sockets, modules and cables you fit yourself.
Don’t want to fabricate the PCB yourself? Buy a pre-assembled circuit board (PCB only) here
Shipping
Thank you for your PCB order.
Your payment was successful. This order is the pre-assembled circuit board (PCB only).
Sorry, something went wrong.
Please try checkout again, or get in touch and we will help you directly.
Secure checkout via PayPal (PayPal account or credit / debit card). Widerrufsbelehrung · Vertrag widerrufen
02 Add the Teensy
- Solder two compatible 8 MB PSRAM chips to the Teensy 4.1 underside for 16 MB total. Align pin 1 using PJRC’s placement photos, inspect for bridges and run the linked memory test. Confirm 16 MB is detected and passes before fitting the module.
- Solder two 1×24 male headers, 2.54 mm pitch, along the Teensy edges. Keep them straight. Fit four 1×12 female carrier sockets, 3M 929870-01-12-RA (DigiKey), at J28–J31. CN1/CN2 are already fitted by JLCPCB; check they contact the Teensy USB-device D−/D+ pads and allow clearance for the PSRAM.
- Inspect the JLCPCB-assembled carrier, including the jacks, JST-PH headers, encoder sockets, power switch, microphone and pogo pins. Match the assembled parts to the schematic before powering up.
- Bridge JP1 center to VYS for normal USB/battery operation. Center to VBUS is the USB-only option. Bridge one gap only. Bridging both joins raw USB power to the charger output. Check VIN/VUSB isolation if also plugging into the Teensy’s own USB socket while the carrier supplies VIN.
03 Add the DuPPa encoders
Solder each DuPPa V2.1 RGB encoder and its two 1×5 headers. Set the four module addresses from left to right to 0x01, 0x41, 0x20, 0x61: close A0; A6+A0; A5; A6+A5+A0 respectively. Leave other address jumpers open. Carrier encoder header pins are 1 GND, 2 +5 V, 3 SDA, 4 SCL, 5 INT; match module labels before seating.
04 Wire the matrix, clocks and speaker
Use the standard touchpads with inlay pieces fitted into the touchpad assembly. The build needs one 5-pin touch cable, four 2-pin speaker/clock-jack cables, and one 3-pin LED-panel cable, JST-PH 2.00 mm. Pin numbers are PCB pins, not wire colours.
| Connection | Wire it this way |
|---|---|
| Matrix · J9 | 1 → DIN, 2 → GND, 3 → +5 V. One 32×16 panel; firmware LED mode 2 addresses its 512 LEDs. |
| Clock out · J25 | 1 → TS jack tip, 2 → sleeve/GND. Buffered 5 V output (Teensy 37). |
| Clock in · J26 | 1 → TS tip, 2 → sleeve/GND. Buffered 3–5 V input (Teensy 38). |
| Sidechain out · J27 | 1 → TS tip, 2 → sleeve/GND. Buffered 5 V voice trigger (Teensy 28). |
| Speaker · J10 | 1 → ROUT−, 2 → ROUT+. Neither wire goes to GND. |
| Touch · J13 | Pin 1 touch 1 (GPIO 2), pin 3 menu (GPIO 3), pin 2 touch3 (GPIO 4), pin 4 audition (GPIO 6), pin 5 FN (GPIO 39). |
| Battery · J16 | 1 → GND, 2 → VBAT. Check the LiPo plug polarity first. |
05 Cut the case
- Choose 32_16.dxf plus COMMON.dxf for the standard desktop housing; 16_16.dxf is the smaller optional build. For the modular panel choose modular_2parts.dxf or its two separate base/front files. Import in millimetres at 1:1; do not cut both the combined file and its separate copies. The modular base is 182.5 × 128.5 mm and the front is 172 × 86 mm.
- Separate SCHNITT (cut) from GRAVUR (engrave). Exclude reference clearance guides. Convert text to outlines if your laser software cannot use Space Grotesk Bold.
- Start with a 0.125 mm offset into the waste: outside the outer perimeter and inside holes/cutouts. Software asking for full kerf width needs 0.250 mm for that offset. Check the preview and apply compensation only once.
- Cut a fit coupon in the actual laser-safe acrylic first. Adjust kerf to the machine/material and confirm sheet thickness against your stack. The modular illustration uses a 2 mm base, 8 mm LED and 2 mm front; verify the real clearances before ordering sheets.
- Engrave first, cut holes next, outer profiles last. Dry-fit everything and check the panel, PCB and LED clearances before final assembly. Mount the PCB flat underside toward the panel.
Follow the modular laser notes for the mounting orientation. The older browser case generator uses an older board template; verify rev H holes before cutting from it.
06 Power on
Leave the battery, Teensy and matrix disconnected for the first carrier check. With JP1 bridged and the switch on, check the 5 V, 3.3 V and 1.8 V rails. Power off, fit the tested Teensy, then reconnect and check again.
Build with pio run -d platformio from the repository root, or use the flashing instructions. The firmware uses USB Serial + MIDI + Audio. Add the microSD and matrix with power off, test the four encoders and headphone audio, then enable the optional speaker in VOL → SPKR. Connect the battery after the USB-powered checks pass.
Try the handbook’s first beat. For the display Demo, open ETC → INFO and press touch3 / BUTTON_C; press and release Touch 1 / BUTTON_A to return.
Parts list, BOMs and drawings
Full assembly guide Purchasing BOMs Housing DXFs
| Qty | Part | What to check |
|---|---|---|
| 1 | Assembled rev H PCB | Secure SGTL5000XNBA3 and all unavailable assembly parts before ordering. |
| 1 + 2 | Teensy 4.1 + 8 MB PSRAM chips | 16 MB total; two 1×24 male headers if the Teensy has no pins. |
| 4 sets | DuPPa I2C Encoder V2.1, RGB encoder, knob | Two 1×5 male headers each; check which accessories the bundle includes. |
| 1 | 32×16 RGB LED panel | Standard 512-LED display; J9 3-pin mating cable. 16×16 is optional. |
| 5 + 1 set | Touchpads + inlay | Fit the inlay into the touchpad assembly. Four grounded buttons are the external-panel alternative. |
| 4 | 1×12 Teensy carrier sockets | 3M 929870-01-12-RA, DigiKey; solder at J28–J31. |
| 3 | Clock/sidechain TS panel jacks (Amazon source) | Match panel holes; solder each jack to a 2-pin cable from the four-lead total below. |
| 1 | Speaker (optional) | Solder speaker leads to a JST-PH 2.00 mm 2-pin mating cable for J10. Neither terminal is GND. |
| 1 | JST-PH 5-pin cable | 2.00 mm pitch; five touchpads on J13. |
| 4 | JST-PH 2-pin cables | 2.00 mm pitch; one for the speaker and three for clock/sidechain jacks. |
| 1 | JST-PH 3-pin cable | 2.00 mm pitch; LED panel on J9. |
| 1 | Single-cell LiPo (optional) | JST-PH plug; verify polarity and case fit. |
| 1 each | microSD + USB-C data cable | 32 GB FAT32 or 64 GB exFAT; load the sample folders onto the card. |
| 1 set | Laser-safe acrylic | Match the housing and measured stack. |
Hardware files are CC BY-NC 4.0 for personal/non-commercial builds. Commercial hardware sales require written permission; see the license.
Open & Hackable.
Firmware is MIT. Hardware design files are CC BY-NC. The handbook is how you play it.
Contribute
TŒRN is open source. Use the firmware, and hardware files; build - and share what you make. PCB, source code, and docs are on GitHub.
See It In Action
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Buy TŒRN
- One TŒRN unit - sequencer, sampler and synth groovebox
- 17 × 17 × 5 cm, about 480 g
- DIY kit, partially assembled
- 32×16 layout. If you need a 16×16, contact me via the imprint.
- Standalone - no laptop or DAW needed to play
-
Powered via USB-C, also battery-ready — has to be ordered from 3rd party
Battery: 503759 3.7V 1500 mAh, PCM, JST PH2.0-2P Plug — example (Amazon). Max thickness 5 mm, up to 3000 mAh should work. Cut the foam so the cell fits. Plug pin 2 is positive (VBAT).
Power Supply: any suitable USB-C power supply with more than 2A should be fine, e.g. IKEA SJÖSS — IKEA SJÖSS
- When it arrives, open the handbook and play the first beat
- MicroSD card for samples is included
- Unit and packaging. Shipping for Germany and EU is added at checkout.
TŒRN is a small-batch instrument from an independent maker, not a mass-produced product. It is tested, and it can still have rough edges. Firmware is MIT. Hardware design files are CC BY-NC.
Shipping
Built first, then shipped. About 5–10 weeks after your order.
Secure checkout via PayPal (PayPal account or credit / debit card). Widerrufsbelehrung · Vertrag widerrufen
Shipping
Shipped via DHL. Germany and EU shipping are added at checkout, on top of the unit price. The unit price does not include shipping.
Customs, Tax
EU: Total includes VAT (19%).
Other: Customs and/or import tax may apply upon import.
You may declare the revocation of your contractual statement in text form (e.g. letter, email) or by returning the merchandise within a period of two weeks. The revocation does not have to contain any reason. We will forward this revocation instruction to you again in text form. The revocation period commences the day following the receipt of merchandise and this revocation instruction in text form. The time-limit shall be deemed to be observed by the timely dispatch of the declaration of revocation or the return shipment.
The revocation is to be addressed to:
E-Mail: info@toern.live
Postal:
warft_labs
Schanzenstraße 35
20357 Hamburg
GERMANY
Personal data you provide for ordering are used for order processing and communication directly related to the order (such as invoice, shipment notification) only. This information is not shared with third parties and will be stored as long as required by law. When ordering through PayPal, your personal data are collected by PayPal and PayPal's privacy policy will apply, too.
Order & Shipping
When will my TŒRN ship?
Your TŒRN is built first, then shipped. That takes about 5–10 weeks after your order.
You’ll get production updates by email.
Can I cancel my order?
You may cancel your order for a full refund at any time before production begins.
Once production has started, cancellation may no longer be possible.
After delivery, the statutory 14-day right of withdrawal applies in accordance with EU consumer law.
To request a cancellation or withdrawal, please contact us at info@toern.live.
Is there a warranty?
Yes. All units are covered by a 2-year warranty in accordance with applicable EU law.
This warranty applies in addition to statutory consumer rights, including rights related to defects and non-conformity.
Where do you ship to?
Orders on this site ship only within the EU.
Standing on good work
TŒRN is a small instrument built on a lot of generous work by other people. None of this would exist without them, so here is where the credit belongs.
First and foremost: thank you to Paul Stoffregen and the PJRC crew. The Teensy 4.1 is the brain of every unit, and the Teensy Audio Library — Freeverb and all — is the reason it sounds like something you want to keep playing. The Teensy cores, WS2812Serial for the LED matrix, and LittleFS and SerialFlash for storage come from the same place. An enormous amount of TŒRN is really their work, carefully wrapped in a box with knobs.
An especially loud shoutout goes to Nic Newdigate, whose teensy-polyphony and teensy-variable-playback are the polyphonic heart of this instrument. And a warm thank you to signaturesounds.org for providing such awesome sounds and samples — a sampler is only as good as what you feed it.
Plenty of other projects are doing quiet, essential work in the background: the Arduino MIDI Library by FortySevenEffects keeps TŒRN in time with the rest of your studio, FastLED paints every pixel you see, Adafruit’s BusIO and seesaw libraries talk to the hardware, DuPPa’s ArduinoDuPPaLib drives the encoders, Adrian Freed’s FastTouch reads your fingertips, natnqweb’s Mapf does the maths nobody wants to write twice, Bill Greiman’s SdFat sits behind every sample you load and save, and Teensy Loader puts new firmware on your unit from the browser.
And thank you to the wider open-source audio community, for sharing the kind of knowledge that lets one person build a synth in the first place. Full credits and licenses live in the git repository.
toern won Gold in the category Realities at the HAIC Award.
MiniBooth Berlin 2026 is where toern was first presented to the public.