HardLabs

Firestring

thip·firestring·hardware/FireString.kicad_pcb

Firestring PCB layout, top view — open source RP2040/RP2350 board by thip
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About the Firestring PCB

Firestring is an open source RP2040/RP2350 PCB design by thip, published on GitHub under the CC-BY-NC-4.0 license. It is a 2-layer board measuring 40 × 18 mm, with 36 components from 19 distinct parts.

Its main chip is the RP2040, from the RP2040/RP2350 family. Other key parts include the AP2112K-3.3, USBLC6-2P6 and W25Q16JVUXIQ. By type, the board carries 20 capacitors, 9 resistors, 4 ICs, 1 crystal, 1 connector and 1 switch.

It belongs with the displays & leds designs in this gallery.

From the project

FireString - RP2040-based NeoPixel fire simulation controller

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.

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…

Main components on the Firestring

AP2112K-3.3USBLC6-2P6W25Q16JVUXIQRP2040

Firestring bill of materials (BOM)

36 components, 19 distinct parts.

QtyPartRefs
1
AP2112K-3.3
U1
1
USBLC6-2P6
U2
1
W25Q16JVUXIQ
U3
1
RP2040
U4
1
12MHz
Y1
1
USB_C_Receptacle_USB2.0_16P
J1
1
~
SW1
1
4.7n
C1
3
10u
C2, C3, C10
11
100n
C4, C5, C6, C9, C11, C12, C13, C14 +3
2
1u
C7, C8
2
27p
C16, C17
1
100u
C20
1
1M
R1
2
5.1k
R2, R3
2
10k
R4, R8
1
1K
R5
2
27.4
R6, R7
1
100
R9

Firestring design files

The KiCad project lives in the thip/firestring repository on GitHub; these links point at the commit this page was built from.

Firestring: common questions

What microcontroller does the Firestring use?

The Firestring is built around the RP2040, from the RP2040/RP2350 family.

How big is the Firestring PCB?

The Firestring measures 40 × 18 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Firestring?

36 components, from 19 distinct parts. The full bill of materials is listed on this page.

Where can I download the Firestring design files?

From the thip/firestring repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the Firestring design in my own project?

It is published under CC-BY-NC-4.0, which limits how it may be reused; read the license before building on it.

Can I test firmware for the Firestring without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug RP2040/RP2350 firmware against it before you order a PCB.

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