Why2025
About the Why2025 PCB
Why2025 is an open source ESP32 PCB design by ranzbak, published on GitHub. It is a 4-layer board measuring 114.9 × 129.9 mm, with 327 components from 84 distinct parts.
Its main chip is the ESP32-C6-WROOM-1, from the ESP32 family. Other key parts include the CH32V203C8T6, TLV62569DBV, CH334R, BQ25895RTW and CH340K. By type, the board carries 91 capacitors, 88 resistors, 87 diodes, 32 ICs, 12 connectors and 6 transistors.
It belongs with the wearables designs in this gallery.
From the project
Hardware design files for the WHY2025 badge
This repository contains the hardware design files for the WHY2025 badge.
Detailed information can be found on our website.
Need the schematic? It's in this repository as a PDF file.
This hardware design may be used under the terms of the CERN-OHL-P license.
All organization names, logos and trademarks such as but not limited to the Badge.Team name, logo and mascots, the WHY2025 name and logo and the Nicolai Electronics name and logo are all rights reserved for their respective owners and may not be reproduced on derrivative works.
Main components on the Why2025
Why2025 bill of materials (BOM)
327 components, 84 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | CH32V203C8T6 | LQFP-48_7x7mm_P0.5mm | U1 |
| 1 | TLV62569DBV | SOT-23-5 | U3 |
| 1 | CH334R | QSOP-16_3.9x4.9mm_P0.635mm | U4 |
| 1 | ESP32-C6-WROOM-1 | ESP32-C6-WROOM-1 | U5 |
| 1 | BQ25895RTW | Texas_S-PWQFN-N24_EP2.7x2.7mm_ThermalVias | U6 |
| 1 | CH340K | SSOP-10-1EP_3.9x4.9mm_P1mm_EP2.1x3.3mm | U7 |
| 1 | ESP32-P4 | QFN-104_EP_10x10_Pitch0.35mm-ESP32-P4 | U8 |
| 6 | SK6805 | SK6805-EC20 | U9, U17, U18, U19, U22, U32 |
| 1 | BHI360 | XDCR_BHI360 | U10 |
| 2 | AP3032KTR | SOT-23-6 | U11, U12 |
| 1 | W25Q128JVS | SOIC-8_5.23x5.23mm_P1.27mm | U13 |
| 1 | ES8156 | VQFN-20-1EP_3x3mm_P0.4mm_EP1.7x1.7mm | U14 |
| 1 | LR8341A-M25 | SOT-89-3 | U15 |
| 1 | FM8002A | SSOP-8_3.9x5.05mm_P1.27mm | U16 |
| 1 | C426705 74LVC1G17GW,125 | SOT-353_SC-70-5 | U20 |
| 1 | C2652381 PCA9517DP,118 | TSSOP-8_L3.0-W3.0-P0.65-LS4.9-BL | U21 |
| 1 | TPS63020DSJR | VSON-14_L4.0-W3.0-P0.50-BL-EP_TI_DSJ | U23 |
| 1 | SY6280AAC | SOT-23-5 | U24 |
| 1 | 65K5. | SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR | U25 |
| 1 | 74LVC2G02HD4-7 | X2-DFN2010-8_L2.0-W1.0-P0.50-BL | U26 |
Show 64 more
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 2 | USBLC6-2P6 | SOT-666 | U28, U29 |
| 2 | C5180236 ESD | Diodes_UDFN-10_1.0x2.5mm_P0.5mm | U30, U31 |
| 1 | BME688_C3664478 | LGA-8_L3.0-W3.0-P0.80_BME688 | U33 |
| 1 | BMI270 | LGA-14_L3.0-W2.5-P0.50-BR | U34 |
| 4 | AP2302B | SOT-23 | Q1, Q2, Q3, Q4 |
| 2 | C2938367 AO3400 (A09T) | SOT-23 | Q5, Q6 |
| 1 | 12MHZ 12MHz | Crystal_SMD_2520-4Pin_2.5x2.0mm | Y1 |
| 1 | 32.768KHZ 32.768KHz | Crystal_SMD_3215-2Pin_3.2x1.5mm | Y2 |
| 1 | 40MHZ 40MHz | Crystal_SMD_3225-4Pin_3.2x2.5mm | Y3 |
| 1 | C3036280 DF37NB-24DS-0.4V(51) | CONN-SMD_DF37NB-24DS-0.4V | CN1 |
| 1 | C165948 USB device | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
| 1 | C42576 USB host | USB-A-TH_JTJ-USB-A-F-10.0-010 | J2 |
| 1 | LoRa | SMA_Samtec_SMA-J-P-H-ST-EM1_EdgeMount | J3 |
| 1 | C319103 Headphone | PJ-327ST-SMT | J4 |
| 1 | C2936004 External Add-On (SAO / PMOD) | PinSocket_2x07_P2.54mm_Horizontal | J5 |
| 1 | C3975163 Internal Add-On | PinSocket_2x18_P2.54mm_Vertical_SMD | J6 |
| 1 | C189700 Speaker | Molex_PicoBlade_53261-0271_1x02-1MP_P1.25mm_Horizontal | J7 |
| 1 | C7529389 Micro_SD_Card | SD_Card-micro_socket_A | J8 |
| 1 | C597981 CAMERA | Hirose_FH12-22S-0.5SH_1x22-1MP_P0.50mm_Horizontal | J9 |
| 1 | C160404 Expansion I3C | 1X04_1MM_RA_GND | J10 |
| 1 | C265329 Battery | JST_S2B-ZR-SM4A-TF(LF)(SN) | J13 |
| 1 | C318992 Power | KEY-TH_TC-1101V-C-A-W | SW1 |
| 1 | C318992 User | KEY-TH_TC-1101V-C-A-W | SW2 |
| 1 | C318992 Boot | KEY-TH_TC-1101V-C-A-W | SW3 |
| 72 | 1N4148WS | D_SOD-323 | D1, D2, D3, D4, D5, D6, D7, D8 +64 |
| 8 | LTW-010DCG-SR-G | LTW-010DCG-SR-G | D73, D74, D75, D76, D77, D78, D80, D81 |
| 2 | 2.0V 2.0v | D_SOD-123 | D79, D85 |
| 1 | C7371898 Purple LED | LED_0603_1608Metric | D82 |
| 2 | 1N5819WS | D_SOD-323 | D83, D84 |
| 1 | 2.7V 2.7v | D_SOD-323F | D86 |
| 1 | SMD24PL-TP | SOD-123_L2.8-W1.8-LS3.7-RD | D87 |
| 1 | 2.2U 2.2u | Inductor_MSC20FC | L1 |
| 1 | YHNR4020-2R2M | L_Wurth_WE-LQSH-4020 | L2 |
| 2 | 6.8UH 6.8uH | IND-SMD_L4.0-W4.0 | L4, L6 |
| 1 | CMLW6028S1R5MST | IND-SMD_L6.0-W6.0 | L7 |
| 37 | 100N 100n | C_0402_1005Metric | C1, C2, C3, C4, C5, C6, C10, C16 +29 |
| 17 | 10U 10u | C_0805_2012Metric | C7, C13, C14, C15, C20, C25, C29, C31 +9 |
| 17 | 1u | C_0603_1608Metric | C8, C9, C18, C19, C30, C32, C34, C39 +9 |
| 1 | 47N 47n | C_0603_1608Metric | C11 |
| 1 | 4U7 4u7 | C_0603_1608Metric | C12 |
| 6 | 22P 22p | C_0402_1005Metric | C21, C22, C47, C48, C71, C72 |
| 4 | 10N 10n | C_0402_1005Metric | C26, C46, C49, C58 |
| 1 | 0.39U 0.39u | C_0603_1608Metric | C60 |
| 6 | 22U 22u | C_0805_2012Metric | C65, C66, C81, C83, C84, C85 |
| 1 | 220N 220n | C_0603_1608Metric | C78 |
| 21 | 10K 10k | R_0402_1005Metric | R1, R2, R3, R4, R5, R6, R7, R8 +13 |
| 2 | 5K1 5k1 | R_0402_1005Metric | R9, R10 |
| 13 | 4K7 4k7 | R_0402_1005Metric | R11, R23, R42, R45, R60, R61, R65, R66 +5 |
| 11 | 100K 100k | R_0402_1005Metric | R12, R27, R31, R32, R39, R47, R70, R71 +3 |
| 5 | 2K2 2k2 | R_0402_1005Metric | R13, R15, R19, R46, R86 |
| 19 | 51K 51k | R_0402_1005Metric | R16, R25, R26, R30, R33, R34, R35, R36 +11 |
| 2 | 27 | R_0402_1005Metric | R17, R18 |
| 1 | 261 | R_0402_1005Metric | R20 |
| 2 | 499K 499k | R_0402_1005Metric | R40, R41 |
| 2 | 4K02 4k02 | R_0402_1005Metric | R44, R52 |
| 1 | 4R7 | R_0402_1005Metric | R48 |
| 1 | 10 | R_0402_1005Metric | R51 |
| 1 | 1M | R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R64 |
| 2 | 33 | R_0402_1005Metric | R67, R68 |
| 1 | 0 | R_0402_1005Metric | R69 |
| 1 | 180K 180k | R_0402_1005Metric_Pad0.72x0.64mm_HandSolder | R73 |
| 1 | 6.8K 6.8k | R_0402_1005Metric | R78 |
| 1 | 1.5K 1.5k | R_0402_1005Metric | R83 |
| 1 | 1k | R_0402_1005Metric | R85 |
Why2025 design files
The KiCad project lives in the ranzbak/why2025-hardware repository on GitHub; these links point at the commit this page was built from.
- Layoutwhy2025.kicad_pcb
- Schematicwhy2025.kicad_sch
- BOMproduction/bom.csv
Why2025: common questions
What microcontroller does the Why2025 use?
The Why2025 is built around the ESP32-C6-WROOM-1, from the ESP32 family.
How big is the Why2025 PCB?
The Why2025 measures 114.9 × 129.9 mm, has 4 copper layers and is 1.6 mm thick.
How many components are on the Why2025?
327 components, from 84 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the Why2025 design files?
From the ranzbak/why2025-hardware repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the Why2025 design in my own project?
The repository has no license, so all rights stay with ranzbak. Use it as a reference, and ask the author before reusing the design.
Can I test firmware for the Why2025 without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug ESP32 firmware against it before you order a PCB.
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