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YOU CAN BUILD AN INSTRUMENT THAT PLAYS LIGHT INSTEAD OF SOUND

An instrument you play with four knobs, and 8,192 pixels answer the moment you turn one.

by engmung

FULL CAD BOM FIRMWARE DOCS

DisplaysAudio

Built withESP32Raspberry Pi3D printing

difficulty
●●●○○
time
a weekend
license
CC-BY-SA-4.0
repo
repo ACTIVE340 stars

WHAT YOU’LL NEED

Videos
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COMPAREE VERDICT

Patternflow is an LED synthesizer: four rotary encoders control generative light patterns across a 128×64 LED matrix, 8,192 pixels total, with every frame computed live on an ESP32. The repository gives you a complete BOM, printable enclosures for two bed sizes, knobs, firmware and a step-by-step build guide. Two features that now define the instrument — web upload and .pfm pattern modules — were contributed by the community, not the original maker, which is rare honesty in a repository. Builders in six countries have made working units, including a Raspberry Pi port and two in DJ booths. The one thing most likely to go wrong is the LED matrix itself: HUB75 panels are not all equal: some driver chips stay dark or misbehave on a bare ESP32-S3, which is why the repository ships a panel-compatibility guide and links a verified panel in the BOM. The build is accessible if you have soldered before, but tuning a pattern to look good is its own skill — expect to spend more time writing or tweaking patterns than assembling the hardware. If you want a screen that responds rather than just plays back, and you are comfortable with the photosensitivity warning the project itself publishes, this is a weekend that will sit on your desk and keep teaching you things.

GOOD TO KNOW

  • —The repository contains a BOM as CSV, STL files for enclosures in two printer bed sizes, printable knobs, ESP32 firmware, and an illustrated build guide.
  • —Code is MIT, hardware is CC BY-SA 4.0 — both permit commercial use with attribution and the hardware licence requires sharing modifications under the same terms.
  • —Pattern modules (.pfm files) are documented and the web upload interface is included.
  • —The project carries a photosensitivity warning: rapidly changing light patterns can trigger seizures in people with photosensitive epilepsy.
  • —A Crowd Supply campaign exists but is not required — all build files are public.
  • —Community contributors built the web upload and pattern module loader; the maker integrated them after hardware proof.

Parts to buy

6 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • 128×64 HUB75 P2.5 LED matrix panel (320×160 mm)Find
  • Project's custom PCB (Gerbersfrom the repo files
  • ESP32-S3 DevKitC-1 N16R8 board (16 MB flash, 8 MB PSRAM)Find
  • Four EC11 rotary encoders with push switchFind
  • M4 panel screwsFind
  • 5 V USB power bankFind

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Can I build this?

PrintEnclosure in two sizes (standard and large bed), four knobs
Buy128×64 HUB75 P2.5 LED matrix panel (320×160 mm), the project's custom PCB (Gerbers in the repo) with its small parts, an ESP32-S3 DevKitC-1 N16R8 board (16 MB flash, 8 MB PSRAM), four EC11 rotary encoders with push switch, M4 panel screws, a 5 V USB power bank. A breadboard route without the PCB is also documented.
ToolsSoldering iron, 3D printer, wire strippers, multimeter helpful
SkillsComfortable soldering, basic 3D printing; flashing is done from the browser, and new patterns can be made in the browser editor without writing code yourself, though reading JavaScript helps with fine-tuning.
TimeA weekend once parts arrive (allow about 2 weeks for shipping): about 10 hours of unattended printing, about 1 hour of soldering and assembly, then flashing and first patterns.
Cost$$, dominated by the LED matrix panel (price varies by supplier and flicker tolerance)
SafetyPhotosensitivity warning from the project itself: rapidly changing light patterns can trigger seizures. If anyone with photosensitive epilepsy will be near it, do not build this. Power is 5 V DC from a USB power bank, not mains, but a pattern that fills the screen with white draws about 4.8 A, more than a typical USB-A port is rated for, and warms the connector, so avoid near-white full-screen patterns until the firmware power clamp lands.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

The maker's own film, linked from the README, covers what Patternflow is, how it is built and why it exists.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the illustrated build guide in the repository (Start here, not with ordering parts — the guide shows which panel types work and which do not.)
  2. 2.Order the BOM from the CSV in the repo (The LED matrix is the only part where supplier matters. Buy the BOM-linked panel, or check the panel-compatibility guide before choosing another.)
  3. 3.Print the enclosure and knobs while parts arrive (Two bed sizes are provided. A 256 mm bed is enough: the frame prints in halves that you glue together. A bed of about 330 mm prints the body in one piece with no gluing. Neither version needs the panel trimmed.)
  4. 4.Flash the firmware and test the panel before final assembly (One bad solder joint or a flickering panel is easier to fix before everything is in the case.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Not all HUB75 panels work: some driver chips leave the panel completely black on a bare ESP32-S3, and listings rarely name the chip. Buy the verified panel from the BOM, or follow the repository's panel-compatibility guide (read buyer reviews for ESP32 reports) before you order.
  • Any 5-pin EC11 encoder with a push switch works, but the cheapest packs fail more often. The reference part is the Bourns PEC11R-4220F-S0024 with a 20 mm shaft; if you use 15 mm shafts, print the matching knob file. If a knob reads backwards or skips, fix it per knob on the device's /knobs page, no rebuild needed.
  • Writing a good pattern is its own skill. The project gives you a Pattern Guide, a browser Live Editor with dozens of presets to remix, and Wi-Fi upload, but expect your first patterns to be tweaks of existing ones.
  • The photosensitivity warning is real. If anyone with photosensitive epilepsy will be near this, do not build it. Rapidly changing light is the entire point of the device.
  • On a 256 mm bed the enclosure frame and back panel print in halves that you glue together with CA glue (about 10 hours of printing in total), and a bonded seam shows a hairline gap when backlit. The LED panel goes in with near-zero clearance, so work it in slowly.

Can I use a different microcontroller?

A Raspberry Pi port exists in the community, but it is not in the main repository. The ESP32 is the supported board and the firmware is written for it.

Is the LED matrix the same as the ones used for P5 or P10 outdoor signs?

Same family, but not every panel works. Patternflow needs a HUB75E 128×64 P2.5 panel (320×160 mm) whose driver chip works with a bare ESP32-S3; the BOM links a verified one and the panel-compatibility guide explains how to check others.

Can I load new patterns without reflashing firmware?

Yes. The web upload interface and .pfm pattern module loader are both included, and both were contributed by the community.

Is there a library of patterns I can download?

Yes. The community wall has more than a hundred patterns you can pull onto your device over Wi-Fi, and the browser Live Editor includes 42 presets you can remix.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

Two of the defining features — web upload and pattern modules — were contributed by the community, not the original maker. What would you build into yours?

CompareeTEAM1mo agoedited

Practical notes from our verification: the BOM, enclosures, PCB files, firmware and illustrated build guide are all in the repository, and the panel question is covered too: a dedicated panel-compatibility guide explains how to vet HUB75 listings and what fails, and the BOM links a verified panel. The brain is an ESP32-S3 DevKitC-1 in the N16R8 variant (16 MB flash, 8 MB PSRAM); an older plain ESP32 or a smaller-memory S3 is not the part the firmware targets. Cheaper AliExpress S3 modules usually work, and if yours has the cold-boot issue, one 10k resistor fixes it. The project publishes its own photosensitivity warning: Patternflow displays rapidly changing light patterns that may trigger seizures in people with photosensitive epilepsy, and you should stop using it immediately if you feel any discomfort. You do not need to touch firmware to make new patterns: there is a browser Live Editor, a pattern guide, and a community wall with more than a hundred patterns. A Crowd Supply campaign exists but is not required; all files are public, and the README shows seven community builds made around the world. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

engmung

The maker's starting point was Nam June Paik's Participation TV from 1963, an artwork where you speak and the screen moves with your voice. Two months after standing in front of it, they wired an LED matrix to a potentiometer for the first time. When build requests outnumbered buy requests, everything went public.

GitHub

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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