2 layers39.1 × 68.9 mm
BaseChipOnly
ZonatedCord/Yggdrasill
Smart LED plant pot — ESP32 PCB, WS2812B/SK6812 LEDs, WLED firmware, modular 3D-printed vase, and a native iOS app with Apple's Liquid Glass design.
31 parts1
2 layers39.1 × 68.9 mm
BaseChipOnly
ZonatedCord/Yggdrasill1Smart LED plant pot — ESP32 PCB, WS2812B/SK6812 LEDs, WLED firmware, modular 3D-printed vase, and a native iOS app with Apple's Liquid Glass design.
- Size
- 39.1 × 68.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 34
- Nets
- 50
- Pads
- 145
- Tracks, vias
- 169, 39
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 4 Jun 2026
- Updated
- 26 Oct 2026
Overview
BaseChipOnly is an open-source printed circuit board by ZonatedCord, from the ZonatedCord/Yggdrasill repository on GitHub. It is a 2-layer board of 39.1 × 68.9 mm with 34 parts on 50 nets, routed with 169 tracks and 39 vias.
It is built around the ESP32-WROOM-32U, LM2596S-ADJ and USBLC6-2SC6, with the MMBT3904, SMAJ5.0A and SS34 among its other parts. Its parts include 6 resistors, 4 capacitors, 3 ICs, 3 connectors and 2 diodes. It belongs with the home automation and IoT boards and the ESP32 and RISC-V boards of this library.
Main components
6
ESP32-WROOM-32U
SMD,19.2x18mm-40℃~+85℃ -97dBm 2.4GHz 20.5dBm 3V~3.6V Bluetooth4.2 ESP32-DOWD UART、SDIO、SPI、I2C、GPIO、PWM、ADC、DAC、CAN SMD,19.2x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
LM2596S-ADJ
TO-263-5-40℃~+125℃@(TA) 1 1.2V~37V 150kHz 3A 40V 80uA Adjustable Buck Buck Built-in No TO-263-5 DC-DC Converters ROHSUMWDC-DC Converters
USBLC6-2SC6
SOT-23-60.35pF、0.8pF 100nA 150W@8/20us 15V 2 5V 6A@8/20us 6V ESD SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSUMWESD And Surge Protection (TVS/ESD)
MMBT3904
SOT-23-55℃~+150℃ 1 NPN 100 100nA 200mA 200mW 300MHz 300mV 40V 6V NPN SOT-23 Bipolar (BJT) ROHSJiangsu Changjing Electronics Technology (CJ)Bipolar (BJT)
SMAJ5.0A
DO-214AC(SMA)-65℃~+150℃ 400W@10/1000us 43.5A 5V 7V 800uA 9.2V TVS Unidirectional DO-214AC(SMA) ESD and Surge Protection (TVS/ESD) ROHSMDDESD And Surge Protection (TVS/ESD)SS34
SMA(DO-214AC)-55℃~+125℃ 3A 40V 500uA@40V 550mV@3A Independent SMA(DO-214AC) Schottky Diodes ROHSMDDSchottky Diodes
README
PCB/BaseChipOnly_rev2/README.mdBaseChipOnly — HW Rev 2.0
Base board of the Yggdrasill lamp: ESP32-WROOM-32U running WLED, 5 V input, drives the 9 leaf boards (../Foglia, 15 WS2812B each, wired in parallel). This is the second revision of ../BaseChipOnly (rev 1.03, the board that was actually fabricated and brought up).
How the board works, power budget and WLED settings: docs/base-chiponly-pcb.md.
⚠️ Limitation: verified on paper, not on a real board
Rev 2.0 has not been fabricated or assembled yet. Everything below was checked with design-rule tools, file cross-checks and circuit simulation — nothing has been measured on hardware. Simulations use component models (TI's LM2596 model, generic MMBT3904/SS34/LED models) and assumptions (cable resistance, wire length to the leaves, capacitor derating) that may differ from reality. The firmware/boot of the ESP32 cannot be simulated: "it boots" means EN and IO0 reach the right levels at the right time.
Before trusting it, build one board and follow the first power-up procedure in
docs/base-chiponly-pcb.md, then test the auto-reset withesptool.py flash_id.
Status
| Schematic | complete, ERC 0 errors |
| PCB | complete, DRC 0 errors, schematic ↔ PCB parity clean |
| Fab files | Esportazione-2026-09-30/ (Gerbers, drill, BOM with MPNs, pick-and-place, assembly PDF with values, schematic PDF, 3D preview) |
| Fabricated | no |
| Tested on hardware | no |
Tests performed (all theoretical)
| Test | Tool | Result |
|---|---|---|
| Electrical rules check | KiCad ERC | 0 errors |
| Design rules check + schematic parity | KiCad DRC --schematic-parity | 0 errors, 0 unconnected, 0 parity issues (12 known items: 0.2 mm thermal-via drills of the ESP32 footprint, same as rev 1.03) |
| Copper vs schematic | Gerber X2 pad attributes of the exported front copper | 120 / 120 pads on the right net |
| Pinout of every active part vs datasheet | netlist + datasheets | 0 mismatches (LM2596S-ADJ, USBLC6-2SC6, MMBT3904, diodes, polarised caps, connectors, ESP32) |
| ESP32 strapping pins | netlist review | IO0 pull-up + BOOT; IO2/IO12 floating (download mode OK, 3.3 V flash); IO5/IO15 internal pull-ups |
| Trace current capacity | IPC-2221, 1 oz outer layer, +10 °C | all power traces above their current (e.g. +5V bus 3 mm → 5.3 A for ~3.3 A) |
| Fab limits | JLCPCB rules | tracks ≥ 0.2 mm, vias 0.6/0.3, copper ≥ 1 mm from edge, silkscreen ≥ 0.8 mm / 0.15 mm |
| Mechanical / visual | KiCad 3D render | polarity marks, orientation, ≥ ~1 mm between parts in the regulator block, ≥ 1.1 mm from the ESP32 |
| Auto-reset (both esptool sequences) | ngspice | enters download mode; serial monitor does not reset the board |
| Power-on EN timing | ngspice | EN rises 13.7 ms after 3.3 V (spec ≥ 50 µs) |
| 3.3 V regulator: nominal, LEDs at 3 A, minimum input, start-up | ngspice + Texas Instruments LM2596 model (SNVMA65, credited in LICENSE-NOTICES.md) | 3.28 V, ≥ 3.21 V worst case; needs ≥ ~4.5 V at its input |
| Status LED current | ngspice | 4.6–6.7 mA |
| LED data line to 9 parallel leaves | ngspice | clean ~370/770 ns pulses with R5 = 100 Ω |
Re-run the checks with ./verifica.sh (ERC + DRC/parity + fab export + Gerber cross-check). Simulations: simulazioni/README.md (run simulazioni/models/get_lm2596_model.sh once to fetch the TI model).
Changes from rev 1.03
Bugs fixed (all seen during the rev 1.03 bring-up)
| Rev 1.03 | Rev 2.0 |
|---|---|
| D2 (SS34 catch diode) reversed — shorts the regulator switch node | correct polarity, silkscreen matches |
| D1 (status LED) reversed | correct polarity; GND via moved out of the pad (likely cause of the dark LED) |
| Auto-reset wired wrong: both emitters to GND — idle adapter held the ESP32 in reset, esptool could never enter download mode | standard cross-coupled DTR/RTS circuit, like ESP32 DevKit boards |
| No BOOT / RESET buttons | SW1 BOOT, SW2 RESET (C&K PTS810), centred on the top edge |
| L1 1008 inductor, no value — burned out | Bourns SRN6045TA-101M, 100 µH, Isat 1.33 A |
| Polyfuse 12 A in 0603 — protects nothing | Bourns MF-LSMF400/12X, 4 A hold, 2920 |
| U3 (USBLC6) GND pin unconnected — no ESD protection | GND connected, VBUS to +5V (ST reference circuit) |
| TVS: bidirectional symbol, SMF5.0A part on an SMA footprint | SMAJ5.0A, unidirectional, matches the footprint |
| Reference and Value swapped on the PCB, footprints not linked to the schematic | fixed: correct BOM / pick-and-place, Update-PCB-from-Schematic works |
| 12 ESP32 thermal vias with no net | tied to GND |
| Silkscreen typo "GDN" | "GND" |
Improvements
- COUT2 220 µF tantalum (Kyocera AVX TPSC227M006R0100) next to the 47 µF MLCC, for LM2596 loop stability.
- C4 100 nF → 1 µF (EN delay, Espressif guideline) — from the simulations.
- R5 470 Ω → 100 Ω (clean data pulses to the 9 parallel leaves) — from the simulations.
- Auto-reset transistors specified as MMBT3904 (no part number before).
- +3V3 traces 0.2 → 0.5–1.0 mm; SW node 1.2–1.5 mm.
- New layout: functional blocks, regulator with a short switching loop and room for hand soldering, solid GND plane on the back, no via-in-pad on GND, silkscreen to fab minimums, HW Rev 2.0 printed on the board.
Unchanged on purpose: board outline and mounting holes (the printed base and TasselloFissaggioPCB.stl still fit), J1 barrel jack, J2 terminal, J3 programming header (external USB-UART adapter, no USB-C), ESP32 position, C1, LED data on GPIO13.
Known limits
- The LM2596 needs ≥ ~4.5 V at its input at 500 mA: use a good 5 V 4 A PSU with a short, thick cable and keep the WLED current limiter at 3000 mA.
- The USB-UART adapter must break out DTR and RTS at 3.3 V for the auto-reset; otherwise use BOOT/RESET.
- Button reachability inside the printed base not checked.
Folder contents
| Path | What |
|---|---|
BaseChipOnly.kicad_pro/.kicad_sch/.kicad_pcb | KiCad 9 project |
Esportazione-2026-09-30/ | fabrication files for rev 2.0 |
verifica.sh | all automatic checks in one go |
simulazioni/ | ngspice decks, plots, results |
FIX_LOG.md | session-by-session log of every change (Italian) |
BaseChipOnly-backups/fixpcb_2026-09-30.py, relayout-work/relayout.py, build.sh | scripts that generated the PCB (record of every edit; their input boards live in the local, git-ignored BaseChipOnly-backups/) |
FileImpronte/ | ESP32-WROOM-32U symbol / footprint / 3D model |
Parts
34| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 10k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1, R2, R3, R4 |
| 4 | MountingHole_2.1mm | MountingHole:MountingHole_2.1mm | H1, H2, H3, H4 |
| 2 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C3 |
| 2 | MMBT3904 | Package_TO_SOT_SMD:SOT-23 | EN_CTRL1, IO0_CTRL1 |
| 1 | 1.2k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | Rbot1 |
| 1 | 1000µF | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C1 |
| 1 | 100µH | Inductor_SMD:L_Bourns_SRN6045TA | L1 |
| 1 | 100Ω | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R5 |
| 1 | 1µF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C4 |
| 1 | 2.0k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | Rtop1 |
| 1 | 220µF 6.3V | Capacitor_Tantalum_SMD:CP_EIA-6032-28_Kemet-C_HandSolder | COUT2 |
| 1 | 22µF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | CIN1 |
| 1 | 470Ω | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R0 |
| 1 | 47µF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | COUT1 |
| 1 | 4A | Fuse:Fuse_2920_7451Metric_Pad2.10x5.45mm_HandSolder | Polyfuse1 |
| 1 | BOOT | Button_Switch_SMD:SW_SPST_PTS810 | SW1 |
| 1 | Barrel_Jack_Connector | USBC:BarrelJack | J1 |
| 1 | ESP32-WROOM-32U | USBC:XCVR_ESP32-WROOM-32U | U1 |
| 1 | ESP32_PROG_1x6 | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | J3 |
| 1 | LED | LED_SMD:LED_0805_2012Metric_Pad1.15x1.40mm_HandSolder | D1 |
| 1 | LM2596S-ADJ | Package_TO_SOT_SMD:TO-263-5_TabPin3 | U4 |
| 1 | Morsetto | USBC:Morsetto_3_Vie | J2 |
| 1 | RESET | Button_Switch_SMD:SW_SPST_PTS810 | SW2 |
| 1 | SMAJ5.0A | Diode_SMD:D_SMA | D_TVS1 |
| 1 | SS34 | Diode_SMD:D_SMA | D2 |
| 1 | USBLC6-2SC6 | Package_TO_SOT_SMD:SOT-23-6_Handsoldering | U3 |
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Questions
How big is the BaseChipOnly PCB?
It measures 39.1 × 68.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the BaseChipOnly use?
34 parts, built around the ESP32-WROOM-32U, LM2596S-ADJ, USBLC6-2SC6 and MMBT3904. 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 BaseChipOnly KiCad files?
From the ZonatedCord/Yggdrasill repository on GitHub, at the commit this page was made from: the board is PCB/BaseChipOnly_rev2/BaseChipOnly.kicad_pcb and its schematic PCB/BaseChipOnly/BaseChipOnly.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the BaseChipOnly design in my own project?
Its repository states no licence, so its author keeps all rights: ask ZonatedCord before reusing the design.