2 layers130 × 51 mm
OSUMGP RP2040
NickGuyver/OSUMGP-RP2040
KiCanvas link so you don't have to download to just review the files is here
92 parts18CC-BY-4.0
2 layers40 × 18 mm
Firestring
thip/firestring14FireString - RP2040-based NeoPixel fire simulation controller
- Size
- 40 × 18 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 38
- Nets
- 60
- Pads
- 179
- Tracks, vias
- 318, 80
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 29 Mar 2026
- Updated
- 29 Mar 2026
Overview
Firestring is an open-source printed circuit board by thip, from the thip/firestring repository on GitHub. It is a 2-layer board of 40 × 18 mm with 38 parts on 60 nets, routed with 318 tracks and 80 vias.
It is built around the RP2040, W25Q16JVUXIQ and AP2112K-3.3, with the USBLC6-2P6 among its other parts. Its parts include 20 capacitors, 9 resistors, 4 ICs, 3 connectors and 1 switch. It belongs with the lEDs and displays boards and the RP2040 boards of this library.
Main components
4
RP2040
LQFN-56(7x7)12bit 133MHz 30 LQFN-56(7x7) Microcontrollers (MCU/MPU/SOC) ROHSRaspberry PiMicrocontrollers (MCU/MPU/SOC)
W25Q16JVUXIQ
USON-8-EP(2x3)-40℃~+85℃ 100,000 cycles 10uA 133MHz 16Mbit 2.7V~3.6V 20 Years 3ms SPI USON-8-EP(2x3) NOR FLASH ROHSWinbond ElecNOR FLASH
AP2112K-3.3
SOT253.3V 600mA CMOS Low Dropout Linear Regulator with EnableDiodes IncorporatedUncategorised
USBLC6-2P6
SOT-666-6-40℃~+125℃ 150nA 17V 2 3.5pF 5.25V 5A@8/20us 6V ESD IEC 61000-4-2 Unidirectional SOT-666-6 ESD and Surge Protection (TVS/ESD) ROHSSTMicroelectronicsESD And Surge Protection (TVS/ESD)
README
README.mdFireString
An RP2040-based LED fire simulation controller that drives WS2812B NeoPixel strings to recreate the look of a glowing fireplace.
Full writeup: davidcapper.dev/posts/fire-string
Finished units available at hortus.dev/products/fire-string.
How it works
The simulation is built on three physical concepts:
- Black-body radiation — pixel temperatures are mapped to a colour gradient from red (cool) through orange/yellow to white (hot).
- Heat decay — each pixel loses a proportion of its heat every frame, fading from bright to dark over time.
- Thermal diffusion — pixels transfer heat to neighbours proportionally to temperature difference, so heat spreads naturally through the string.
On top of this, a fuel system adds gradual brightness ramps (fuel converts to heat via a burn rate), and temperature-dependent curves make cool pixels decay slowly and reignite easily while hot pixels shed heat rapidly — mimicking real ember behaviour.
Firmware
CircuitPython running on the RP2040 with @micropython.viper compilation and integer-only maths for performance. Includes a web-based configurator (Web Serial API) for real-time parameter tuning and preset management.
Hardware
Custom 2-layer RP2040 PCB with USB-C, designed in KiCad. Schematic and board layout are in hardware/.
Licence
- Hardware — CC BY-NC-SA 4.0
- Software — MIT
Parts
38| Qty | Value | Footprint | References |
|---|---|---|---|
| 11 | 100n | Capacitor_SMD:C_0402_1005Metric | C4, C5, C6, C9, C11, C12, C13, C14, C15, C18, C19 |
| 3 | 10u | Capacitor_SMD:C_0402_1005Metric | C2, C3, C10 |
| 2 | 10k | Resistor_SMD:R_0402_1005Metric | R4, R8 |
| 2 | 1u | Capacitor_SMD:C_0402_1005Metric | C7, C8 |
| 2 | 27.4 | Resistor_SMD:R_0402_1005Metric | R6, R7 |
| 2 | 27p | Capacitor_SMD:C_0402_1005Metric | C16, C17 |
| 2 | 5.1k | Resistor_SMD:R_0402_1005Metric | R2, R3 |
| 1 | 100 | Resistor_SMD:R_0402_1005Metric | R9 |
| 1 | 100u | Capacitor_SMD:C_1206_3216Metric | C20 |
| 1 | 12MHz | Crystal:Crystal_SMD_Abracon_ABM8G-4Pin_3.2x2.5mm | Y1 |
| 1 | 1K | Resistor_SMD:R_0402_1005Metric | R5 |
| 1 | 1M | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 4.7n | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | AP2112K-3.3 | Package_TO_SOT_SMD:SOT-23-5 | U1 |
| 1 | Conn_01x03_Pin | Connector_JST:JST_XH_S3B-XH-A_1x03_P2.50mm_Horizontal | J2 |
| 1 | RP2040 | Package_DFN_QFN:QFN-56-1EP_7x7mm_P0.4mm_EP3.2x3.2mm | U4 |
| 1 | TC2030-NL | Connector:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical | J3 |
| 1 | USBLC6-2P6 | Package_TO_SOT_SMD:SOT-666 | U2 |
| 1 | USB_C_Receptacle_USB2.0_16P | Connector_USB:USB_C_Receptacle_G-Switch_GT-USB-7010ASV | J1 |
| 1 | W25Q16JVUXIQ | easyeda2kicad:USON-8_L3.0-W2.0-P0.50-BL-EP | U3 |
| 1 | ~ | easyeda2kicad:SW-SMD_L3.9-W3.0-P4.45 | SW1 |
Questions
How big is the Firestring PCB?
It measures 40 × 18 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Firestring use?
38 parts, built around the RP2040, W25Q16JVUXIQ, AP2112K-3.3 and USBLC6-2P6. 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 Firestring KiCad files?
From the thip/firestring repository on GitHub, at the commit this page was made from: the board is hardware/FireString.kicad_pcb and its schematic hardware/FireString.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Firestring design in my own project?
Its repository states no licence, so its author keeps all rights: ask thip before reusing the design.
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