2 layers50 × 40 mm
4 layers25 × 35 mm
A custom low-power stm32-based wearable smart watch
- Size
- 25 × 35 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 49
- Nets
- 57
- Pads
- 196
- Tracks, vias
- 371, 56
- Pours
- 11
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 11 Jul 2025
- Updated
- 2 Aug 2026
Overview
Watch is an open-source printed circuit board by Pedro-Seixas, from the Pedro-Seixas/Custom-Watch repository on GitHub, published under the MIT licence. It is a 4-layer board of 25 × 35 mm with 49 parts on 57 nets, routed with 371 tracks and 56 vias.
It is built around the AP2112K-3.3, LSM6DS3TR-C and N096-2864KSWEG01-H30, with the Q13FC1350000400 and TAXM8M4RDBCCT2T among its other parts. Its parts include 21 capacitors, 9 resistors, 4 switches, 3 ICs and 3 diodes. It belongs with the wearables boards and the STM32 boards of this library.
Main components
5
AP2112K-3.3
SOT253.3V 600mA CMOS Low Dropout Linear Regulator with EnableDiodes IncorporatedUncategorised
LSM6DS3TR-C
LGA-14(2.5x3)-40℃~+85℃ 1.71V~3.6V 16bit 3uA 4KB IMU (accelerometer + gyroscope) SPI、I2C X,Y,Z X,Y,Z ±16g ±2000dps 运动事件检测、同步与时间戳 LGA-14(2.5x3) Accelerometers ROHSSTMicroelectronicsAccelerometers
N096-2864KSWEG01-H30
--40℃~+85℃ 0.96 1.65V~3.3V 120cd/m2 128x64 21.744x10.864mm I2C、SPI Passive (PMOLED) SSD1306 chip White - OLED Display ROHSNewvisioOLED DisplayQ13FC1350000400
SMD3215-2PSMD3215-2P Crystals ROHSSeiko EpsonCrystals
TAXM8M4RDBCCT2T
SMD3225-4P-40℃~+85℃ 10pF 250Ω 8MHz SMD crystal oscillator ±10ppm ±15ppm SMD3225-4P Crystals ROHSYajingxinCrystals
README
README.mdCustom-Watch
A custom low-power stm32-based wearable watch
Features
- 6-Axis IMU Sensor for motion detection and pedometer.
- Temperature Sensor
- OLED Display
- Powered by 3.7V battery or USB
- 2 programmable switches
- Real-Time Clock
- Tap Sensor
Pinout Diagram
Schematic
PCB
Demo (Clock | Menu | Sensors)
TODO
Add deep-sleep to truly be low-power
If you would like to clone the repo, see the "How to" in the Docs folder.
Parts
49| Qty | Value | Footprint | References |
|---|---|---|---|
| 9 | 100nF | Capacitor_SMD:C_0603_1608Metric | C1, C2, C3, C5, C7, C8, C11, C12, C21 |
| 6 | 10kR | Resistor_SMD:R_0805_2012Metric | R1, R2, R3, R5, R6, R7 |
| 6 | 1uF | Capacitor_SMD:C_0805_2012Metric | C6, C13, C14, C17, C18, C23 |
| 2 | 10pF | Capacitor_SMD:C_0402_1005Metric | C9, C10 |
| 2 | 15pF | Capacitor_SMD:C_0402_1005Metric | C15, C16 |
| 2 | 1N5819 | Watch-PCB-Lib:SOD-123_L2.7-W1.6-LS3.7-RD | D1, D2 |
| 2 | SW_Push | Watch-PCB-Lib:SW-Horz | SW3, SW4 |
| 2 | SW_Push | Watch-PCB-Lib:SW-SMD_L3.9-W3.0-P4.45 | SW1, SW2 |
| 1 | 1.5k | Resistor_SMD:R_0603_1608Metric | R4 |
| 1 | 10uF | Capacitor_SMD:C_0603_1608Metric | C4 |
| 1 | 260 | Resistor_SMD:R_0805_2012Metric | R8 |
| 1 | 2uF | Capacitor_SMD:C_0805_2012Metric | C22 |
| 1 | 390kR | Resistor_SMD:R_0805_2012Metric | R9 |
| 1 | AP2112K-3.3 | Package_TO_SOT_SMD:SOT-23-5 | U3 |
| 1 | Conn_01x02_MountingPin | Watch-PCB-Lib:HDR-TH_2P-P2.00-H-M_2005WR-2P | J1 |
| 1 | LED | Watch-PCB-Lib:LED0805-R-RD | D3 |
| 1 | LSM6DS3TR-C | Watch-PCB-Lib:LGA-14_L3.0-W2.5-P0.50-TL | U1 |
| 1 | N096-2864KSWEG01-H30 | Watch-PCB-Lib:OLED_0.96-30P-P0.70-12864 | OLED1 |
| 1 | Q13FC1350000400 | Watch-PCB-Lib:FC-135R_L3.2-W1.5 | X1 |
| 1 | STM32L072CBTx | Package_QFP:LQFP-48_7x7mm_P0.5mm | U2 |
| 1 | TAXM8M4RDBCCT2T | Watch-PCB-Lib:CRYSTAL-SMD_4P-L3.2-W2.5-BL | X3 |
| 1 | USB_B_Micro | Watch-PCB-Lib:MICRO-USB-SMD_5P-P0.65-H-F_C10418 | J3 |
The 45 most common of 49 parts.
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Questions
How big is the Watch PCB?
It measures 25 × 35 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Watch use?
49 parts, built around the AP2112K-3.3, LSM6DS3TR-C, N096-2864KSWEG01-H30 and Q13FC1350000400. 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 Watch KiCad files?
From the Pedro-Seixas/Custom-Watch repository on GitHub, at the commit this page was made from: the board is Docs/Schematic&PCB/watch_project/watch/watch.kicad_pcb and its schematic Docs/Schematic&PCB/watch_project/watch/watch.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Watch design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).