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4 layers21 × 63 mmRfboard, the printed circuit board in 3D

Small blinkenlight boards that sync up using radios

Size
21 × 63 mm
Copper layers
4
Thickness
1.61 mm
Parts
67
Nets
53
Pads
220
Tracks, vias
542, 197
Pours
1
Routed
Yes
KiCad
KiCad 10.0 (file 20260206)
Created
28 Feb 2018
Updated
27 Jul 2026

Overview

Rfboard is an open-source printed circuit board by candykingdom, from the candykingdom/firefly2 repository on GitHub. It is a 4-layer board of 21 × 63 mm with 67 parts on 53 nets, routed with 542 tracks and 197 vias.

It is built around the CH340X, AP2112K-3.3 and ESD5Z5.0, with the 10118194-0001LF and SRV05-4-P-T7 among its other parts. Its parts include 29 capacitors, 15 resistors, 7 diodes, 6 ICs and 4 connectors. It belongs with the radio and wireless boards and the STM32 boards of this library.

Main components

5

README

README.md

Firefly2

Wireless LED control for Burning Man art installations, bikes, and wearables. Devices driving WS2812 strips self-organize over 915 MHz RFM69 radios into a flood mesh with exactly one master, share a network clock via heartbeats, and render effects as pure functions of network time — so every device animates in sync without streaming frames.

New to the project? Start with GETTING_STARTED.md. Working in the code (human or agent)? The mental model lives in docs/index.md and the shared Claude Code/Codex ground rules in CLAUDE.md.

Web simulator (test without hardware)

bash
python3 -m http.server 8642 -d sim
# open http://localhost:8642/

A zero-dependency browser simulator of the whole system: every effect and palette on the real device catalog, synced to a scrubbable network clock, with master-mode autoplay and control overrides. Byte-exact against the firmware (enforced by tests: npm test). See docs/simulator.md.

Building firmware

Firmware builds with PlatformIO (pip install platformio). One env per device target:

bash
pio run -e node                  # SAMD21 rfboard node (node-arm64 on Apple silicon)
pio run -e fancy-node            # STM32G030 node
pio run -e controller            # STM32G070 handheld controller
pio run -e dmx                   # ESP32 DMX bridge
pio run -e fancy-node -t upload  # flash via ST-Link
pio device monitor               # 115200 baud

Note: [env:node]'s bossac platform_packages entry is OS-specific — uncomment the right line in platformio.ini for your OS. Full env/pin/flag details: docs/build-and-test.md.

Programming over USB

The fancy-node device can be programmed either using an STLink, or via USB port. To program via USB, you must first install stm32loader using pip (pip install stm32loader). You may also need to pass the port (typically /dev/ttyUSB0), e.g. pio run -e fancy-node-usb -t upload --upload-port /dev/ttyUSB0.

Saving device description in flash

Both node and fancy-node support reading the DeviceDescription from flash. The modes are defined by the DeviceMode enum within DeviceDescription.hpp. They work as follows:

  • CURRENT_FROM_HEADER: use the current device defined in Devices.hpp
  • READ_FROM_FLASH: read the device saved in flash, if present. If not present (determined by the validity of check_value), fall back to current.
  • WRITE_TO_FLASH: write current to flash, and then use it. This will only write the device to flash if it is different, to avoid causing flash wear.

Tests & linting

The platform-independent core (lib/, src/generic/) builds on the host against fakes, with ASan + UBSan on (and fatal). Requires cmake and a GCC/Clang toolchain (on Windows, use WSL or similar):

bash
mkdir -p build && cd build
cmake .. -DBUILD_SIMULATOR=false   # true builds the SDL desktop simulator too
make && make test
./smalltests --gtest_filter=RadioStateMachineTest*
bash
./lint.sh check     # clang-format, Google style — CI enforces this
./lint.sh format    # format in place
./ci.sh             # exactly what CI runs: cmake + smalltests + largetests
node --test "sim/test/cases/*.test.mjs"   # simulator suite, incl. firmware byte-exactness
npm run test:e2e    # served UI/API/canvas journeys in Chromium and Firefox

CI (GitHub Actions): host tests, lint, node/fancy-node/controller firmware builds, the simulator suite, and CodeQL C/C++ security scanning.

Repo layout

PathContents
lib/, src/generic/Platform-independent core: radio protocol, mesh, effects, LED management
src/arduino/Hardware backends (FastLED, RadioHead RFM69)
src/devices/One main per device target (node, fancy-node, controller, dmx)
test/Host GoogleTest suites + FakeNetwork multi-node mesh simulation
sim/Browser simulator (production C++ renderer via committed Wasm, usable without hardware)
docs/Architecture and per-subsystem notes — start at docs/index.md
hardware/, boards/, bootloader/PCB designs, PlatformIO board definitions, bootloaders
specs/Spec-kit feature specs (spec → plan → tasks workflow, see CLAUDE.md)

For agents & contributors

  • CLAUDE.md — the canonical guidance for Claude Code and Codex, including build commands, architecture, and the invariants you must not break. Codex reaches the same file through AGENTS.md; shared skills remain canonical under .claude/skills/ and are exposed to Codex through .agents/skills/.
  • docs/ — per-subsystem research notes (radio/network, LED/effects, devices, build/test, hardware). Update them when you change documented behavior.
  • Substantial features go through the spec-kit workflow (speckit-specify → plan → tasks → implement; use / in Claude Code or $ in Codex); specs live in specs/.

Parts

67
QtyValueFootprintReferences
16100nFCapacitor_SMD:C_0402_1005MetricC1, C2, C3, C4, C5, C8, C11, C13, C16, C18, C21, C22, C23, C25, C28, C29
610uFCapacitor_SMD:C_0603_1608MetricC6, C9, C12, C14, C17, C20
5ESD5Z5.0Diode_SMD:D_SOD-523D1, D4, D5, D6, D7
410kResistor_SMD:R_0402_1005MetricR9, R10, R13, R15
41kResistor_SMD:R_0402_1005MetricR2, R4, R7, R8
447uFCapacitor_SMD:C_1206_3216MetricC10, C15, C19, C26
3SW_PushHomebrew:SW_TACTILE_5.1MM_TS-1187A-C-D-BSW1, SW2, SW3
20Inductor_SMD:L_0402_1005Metric_Pad0.77x0.64mm_HandSolderL1, L2
2470Resistor_SMD:R_0402_1005MetricR5, R6
25k1Resistor_SMD:R_0402_1005MetricR12, R14
10RCapacitor_SMD:C_0402_1005Metric_Pad0.74x0.62mm_HandSolderC7
110118194-0001LFHomebrew:HRO_TYPE-C-31-M-12J1
115kResistor_SMD:R_0402_1005MetricR11
1220uFCapacitor_SMD:CP_Elec_6.3x5.8C27
122kResistor_SMD:R_0402_1005MetricR3
12337019-1Homebrew:CONN_2337019-1J3
147pFCapacitor_SMD:C_0402_1005MetricC24
14k7Resistor_SMD:R_0402_1005MetricR1
1AP2112K-3.3Package_TO_SOT_SMD:SOT-23-5U5
1CH340XPackage_SO:MSOP-10_3x3mm_P0.5mmU3
1CONN_01X03Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_VerticalP2
1Conn_01x02Homebrew:PinHeader_1x02_P2.54mm_Vertical_NoPlasticJ4
1HX 1210-C06Homebrew:SMD-2P_L2.9-W2.4_C9900033648U6
1REDLED_SMD:LED_0603_1608MetricD2
1RFM69HCWHomebrew:RFM69HCW-minimalpadsU2
1SRV05-4-P-T7Package_TO_SOT_SMD:SOT-23-6D3
1STM32G070KBTxPackage_QFP:LQFP-32_7x7mm_P0.8mmU1
1STRAIN_RELIEFHomebrew:3_pin_2.54mm_pitch_strain_reliefH3
1XL-0807RGBC-WS2812BHomebrew:LED-SMD_4P-L2.0-W1.8_CY-0807U4

Questions

How big is the Rfboard PCB?

It measures 21 × 63 mm and has 4 copper layers, 1.61 mm thick.

What parts does the Rfboard use?

67 parts, built around the CH340X, AP2112K-3.3, ESD5Z5.0 and 10118194-0001LF. 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 Rfboard KiCad files?

From the candykingdom/firefly2 repository on GitHub, at the commit this page was made from: the board is hardware/rfboard/rfboard.kicad_pcb and its schematic hardware/controller/controller.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Rfboard design in my own project?

Its repository states no licence, so its author keeps all rights: ask candykingdom before reusing the design.

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