Sourced from
docs/hardware/bom.mdin the firmware repo.
Bill of materials
Every part needed to build a Nimbus, consolidated across the display configurations, with sourcing links and rough prices. One is hand-built on the Solide S3 board; the other (Configuration B) is a single off-the-shelf all-in-one module with nothing to source beyond the board itself. The modules are all commodity parts - the links below are stable store or search links; any listing matching the Module / chip column works.
Deeper board-level detail (the carrier PCB, per-pin wiring rationale) lives in
the board-support repository:
solide-drivers -
see its docs/build.md and docs/hardware.md.
Prices are approximate 2026 street prices in USD for AliExpress-class sourcing, excluding shipping. Sourcing the branded parts from a US distributor (Adafruit, SparkFun, DigiKey, Mouser) typically adds $15–25 to the total.
Solide S3 build parts
| Qty | Part | Module / chip | Notes | Purchase | ~Price |
|---|---|---|---|---|---|
| 1 | Dev board | ESP32-S3-DevKitC-1 N16R8 | 16 MB QIO flash, 8 MB octal PSRAM. The N16R8 variant specifically - octal PSRAM occupies GPIO 33–37. Espressif's official store sells on AliExpress; also at Mouser/DigiKey. | AliExpress | $12 |
| 1 | Carrier PCB | Custom Nimbus carrier PCB (recommended; optional) | Sockets the DevKit and every module on one board instead of hand-wiring. Order the hardware/fab/ Gerbers from a board house (how to order); hand-wiring on protoboard also works. | JLCPCB (Gerbers in repo) | $2–10 |
| 1 set | Headers | 2.54 mm female pin headers | Socket the DevKit and modules onto the carrier PCB so each stays removable. | AliExpress | $2 |
| 1 | LED ring | WS2812B ring, 45 pixels | Addressable RGB; 5 V power, 3.3 V logic. | AliExpress | $6 |
| 1 | Amp | MAX98357A I²S amplifier breakout | Class-D, built-in thermal and over-current protection. | Adafruit 3006 · AliExpress | $2–6 |
| 1 | Speaker | 4 Ω · 3 W · ~40 mm | The standard MAX98357A pairing. Any small 4 Ω 3 W full-range driver (28–45 mm) works. | AliExpress | $2 |
| 1 | Mic | INMP441 or ICS-43434 I²S MEMS mic breakout | Separate breakout from the amp. 3.3 V only - 5 V damages the S3. | AliExpress | $2 |
| 1 | Storage | microSD module (SPI) | 3.3 V SPI breakout. | AliExpress | $1 |
| 1 | microSD card | 16–32 GB | Must be formatted FAT32 - over-32 GB cards ship exFAT and will not mount without a reformat. | any brand-name card | $5 |
| 2 | Cells | 18650 Li-ion | Wired in series (2S). Buy brand-name cells from a reputable vendor - see the safety note below. Reference pack: owner-measured 3500 mAh, 8.40 V full. | 18650batterystore.com · local vendor | $12 |
| 1 | Charger/protection | 2S BMS with USB-C charging | Protection + balance + charging in one module. | AliExpress | $3 |
| 1 | Regulator | DC-DC buck converter → 5 V | From the 2S pack (~6.0–8.4 V) to a clean 5 V bus, ≥2 A. | AliExpress | $2 |
| 1 each | Battery sense | 220 kΩ + 100 kΩ resistors | Optional but recommended - the pack-voltage divider on GPIO 4. | any electronics supplier · AliExpress kit | $1 |
| - | Misc | wire, protoboard/PCB, JST connectors; optional 330 Ω resistor (LED DIN) and 1000 µF capacitor (ring 5 V/GND) | The resistor and capacitor improve LED reliability on long runs. | AliExpress | $5 |
Shared subtotal: ≈ $55–67 (electronics only; enclosure, fasteners, and pack-build consumables are listed separately below).
Configuration A - Touch TFT
| Qty | Part | Module / chip | Notes | Purchase | ~Price |
|---|---|---|---|---|---|
| 1 | Display | 2.8" ILI9341 SPI TFT, 240×320, with XPT2046 resistive touch | The common SPI module with display pads (SCK/SDI/SDO/DC/RESET/CS/LED) plus a touch header (T_CLK/T_DIN/T_DO/T_CS/T_IRQ). Three on-module solder bridges are required - see the build guide. | AliExpress | $8 |
The touch layer is the input.
Configuration A total: ≈ $59–63 · Build guide →
Configuration B - all-in-one (Freenove CYD)
The lowest-effort build: one part, nothing to wire. The screen, capacitive touch, microSD, mic, speaker, and RGB LED are all on the module. None of the shared parts above are needed - no separate display, LED ring, mic, amp, speaker, SD module, carrier PCB, headers, or battery section for a desk-powered unit.
| Qty | Part | Module / chip | Notes | Purchase | ~Price |
|---|---|---|---|---|---|
| 1 | All-in-one board | Freenove ESP32-S3 Display 2.8" (FNK0104B) | ESP32-S3 N16R8, 2.8" ILI9341 240×320 IPS capacitive touchscreen, on-board microSD, ES8311 mic + speaker, single RGB LED, USB-C. Runs the Nimbus firmware built for SOLIDE_BOARD=freenove_s3. | Amazon B0FSQF6FKN · Freenove | $20–25 |
Nothing else is required. A data-capable USB-C cable for flashing is the only other thing you need, and most people already have one.
Configuration B total: ≈ $20–25 · Pinout & happy-path build →
Safety note - 2S Li-ion
Two 18650 cells in series hold real energy. Buy brand-name cells from a reputable vendor (counterfeits are common), always keep the 2S BMS between the cells and everything else, never charge the pack outside the BMS, tie every ground together, and stop immediately if anything gets warm that shouldn't (a hot SD card or module is an electrical fault - power off first, debug second). The firmware caps LED brightness at 60%: sustained higher levels have been tested and can overheat and damage internal electronics. Do not raise this limit.
Enclosure, fasteners, and assembly consumables
The physical-build extras beyond the electronics - what turns a pile of modules into a finished unit. A 3D printer and a soldering iron are assumed; quantities are approximate. The build photos show every step.
| Qty | Part | Notes | Purchase | ~Price |
|---|---|---|---|---|
| 1 set | 3D-printed enclosure | Print nimbus_classic_case.stl (GitHub renders it in a 3D viewer) in PLA or PETG. | self-print or a print service | $0–15 |
| ~10 | M3 brass heat-set inserts | Melted into the printed case with a soldering iron; screws thread into these. | AliExpress | $5 |
| assorted | M3 machine screws | A short-length assortment, plus a few longer M3 screws for the microSD-module standoff. | AliExpress | $3 |
| 1 | Rocker power switch (SPST) | Cuts the pack to the DC-DC. Generic, ~20 x 12 mm panel cutout. | AliExpress | $1 |
| - | 2S pack build materials | The reference build spot-welds nickel strip to the cells (needs a spot welder), insulates with fishpaper + Kapton tape, and finishes the leads with spade/terminal connectors and silicone hookup wire. No spot welder? Use pre-tabbed cells you solder, or a 2S 18650 holder with leads - see the battery section of the build guide. | AliExpress | $3–8 |
Enclosure + consumables subtotal: ≈ $12–35. Mostly one-time: a spot welder, if you choose to buy one rather than use tabbed cells or a holder, is extra and reusable.
The hardware/fab/
folder also holds the carrier-PCB manufacturing outputs (Gerbers, ODB++) and
how to order the board.