2 layers77.5 × 48.5 mm
4 layers32.4 × 40.2 mm
Smartwatch
Pedro-Seixas/SmartwatchA custom-designed smartwatch built around the ESP32-S3, combining BLE connectivity, a rectangular touch display, recharge capability, IMU and temperature sensors. Designed from the ground up in KiCad.
- Size
- 32.4 × 40.2 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 55
- Nets
- 64
- Pads
- 218
- Tracks, vias
- 558, 156
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 4 Aug 2026
- Updated
- 7 Sep 2026
Overview
Smartwatch is an open-source printed circuit board by Pedro-Seixas, from the Pedro-Seixas/Smartwatch repository on GitHub, published under the MIT licence. It is a 4-layer board of 32.4 × 40.2 mm with 55 parts on 64 nets, routed with 558 tracks and 156 vias.
It is built around the ESP32-S3-WROOM-1-N16R8, TMP112BIDRLR(UMW) and AP2112K-3.3TRG1, with the DW01A, LSM6DS3TR-C and TP4056 among its other parts. Its parts include 18 resistors, 15 capacitors, 8 ICs, 3 diodes and 3 transistors. It belongs with the wearables boards and the ESP32 boards of this library.
Main components
12
ESP32-S3-WROOM-1-N16R8
SMD,25.5x18mm-103.5dBm -40℃~+65℃ 2.4GHz 20.5dBm 355mA 3V~3.6V 95mA ESP32-S3R8 On-board PCB Antenna UART、SPI、I2C、GPIO、I2S、USB SMD,25.5x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
TMP112BIDRLR(UMW)
SOT-563-40℃~+125℃ 1.4V~5.5V 10uA 12bit 26ms I2C、SMBus ±0.5℃ SOT-563 Temperature Sensors ROHSUMWTemperature Sensors
AP2112K-3.3TRG1
SOT-25-5-40℃~+85℃@(Ta) 1 250mV@(600mA) 3.3V 50uVrms 55uA 600mA 65dB@(1kHz) 6V Fixed Over Current Protection、Thermal Shutdown、Enable control Positive SOT-25-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSDiodes IncorporatedVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
DW01A
SOT-23-6L-40℃~+85℃ 1 2.5V 300mV~10V 3uA 4.3V Protection IC Support SOT-23-6L Battery Management ROHSPUOLOPBattery Management
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
TP4056
ESOP-8-40℃~+85℃ 1 1A 35uA 4.2V 4V~6.5V Charging IC Lithium Battery Support Support 恒流充电、恒压充电、涓流充电、自动再充电、充电终止、可编程充电电流、软启动、欠压锁定 ESOP-8 Battery Management ROHSUMWBattery Management
WAFER-PH2.0-2PWZ
弯插,P=2mm-25℃~+85℃ 1 1x2P 2 250V 2A 2P 2mm 4.7mm 6.05mm 6mm Brass PA66 PH Right Angle Tin UL94V-0 White 弯插,P=2mm Wire To Board Connector ROHSXUNPUWire To Board ConnectorYZA-009
-- Tactile Switch/Push Button SwitchYIZHITactile Switch/Push Button Switch
XL-1608UGC-04
0603-40℃~+85℃ 120° 20mA 3.3V 515nm~535nm 525nm 70mW 810mcd Discrete Diode Emerald Green Top-mount Water Clear 0603 LED Indication - Discrete ROHSXINGLIGHTLED Indication - Discrete
1N5819HW-7-F-01
SOD-123Schottky DiodesDiodes Incorporated
AFC01-S18FCA-00
SMD,P=0.5mm,卧贴-45℃~+85℃ 0.3mm 0.5mm 18P 2mm 500mA 50V Bottom Contact Copper alloy Hinged Lid Surface Mount, Right Angle Tin SMD,P=0.5mm,卧贴 FFC, FPC (Flat Flexible) Connector Assemblies ROHSJUSHUOFFC, FPC (Flat Flexible) Connector Assemblies
AO3401A
SOT-231 P-Channel 14nC@10V 30V 47mΩ@10V、60mΩ@4.5V、85mΩ@2.5V 4A 55pF 645pF 80pF 900mV SOT-23 MOSFETs ROHSAlpha & Omega SemiconductorMOSFETs
README
README.mdSmartwatch
A custom-designed smartwatch built around the ESP32-S3, combining BLE connectivity, a rectangular touch display, recharge capability, IMU and temperature sensors. Designed from the ground up in KiCad.
Overview
This is an evolution of an earlier, simpler build (Custom Watch), which used an STM32 MCU with a basic OLED display and IMU. This project pushes further: a more capable MCU, touchscreen input, temperature sensing, and a proper battery charging/protection circuit.
Hardware
- MCU: ESP32-S3-WROOM-1
- Display: 1.69" IPS touchscreen, ST7789V driver, CST816T capacitive touch controller, 4-wire SPI + I2C
- IMU: LSM6DS3TR-C (accelerometer + gyroscope, I2C)
- Temperature sensor: TMP112 (I2C)
- Charging: TP4056 linear Li-ion charger (~150-200mA, PROG resistor configurable)
- Battery protection: DW01A + FS8205A (overcharge, overdischarge, overcurrent, short-circuit protection)
- Power path: AO3401A P-MOSFET + Schottky diode, allowing the board to run directly off USB while charging.
- Battery: 400mAh LiPo, 602530 form factor
Design notes
- Board is organized into hierarchical schematic sheets:
Connectors,Power,MCU,Sensors - Custom KiCad component library (
HW/lib/) built from LCSC/JLCPCB parts viaeasyeda2kicadRepo, with symbols, footprints, and 3D models - ESP32-S3 module's PCB antenna is cantilevered off the board edge with a substrate cutout underneath, for optimal RF performance
- 4-layer stackup: signal / GND plane / power plane / signal
- All components sourced to be JLCPCB assembly-compatible with the exeption of the screen and battery.
Repository structure
HW/ KiCad project (schematics, PCB layout, custom library)
├── lib/ Custom component library (symbols, footprints, 3D models)
├── *.kicad_sch Schematic sheets
├── smartwatch.kicad_pcb PCB layout
└── smartwatch.kicad_pro Project fileLatest PCB Photo
📋 Project Log
Status: Hardware complete (v1.1) · firmware in progress ·
🔧 Firmware: WiFi + on-device settings (Sep 2026)
- LVGL touch UI: menu, clock, sensors, About pages with tap navigation
- On-device settings: set time / date / backlight
- WiFi page with NTP time sync
🔧 Firmware: bring-up & first UI (Sep 2026)
Sensor drivers (IMU, temperature), RTC on a 32.768 kHz crystal, LVGL display + touch working.
🛠️ Hardware v1.1: everything works ✅ (Aug 2026)
Functional test passed. Screen connector fixed. UI phase begins.
⚠️ Known issue → v1.2: LED on GPIO37 conflicts with octal PSRAM — PSRAM off for now.
🛠️ Hardware v1.0: first article (Jul 2026)
All components work; battery charging functional. ⚠️ Screen connector orientation wrong (oops): fixed in v1.1.
Parts
55| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | 100nF | Capacitor_SMD:C_0402_1005Metric | C1, C2, C3, C9, C13, C14, C15 |
| 6 | 10k | Resistor_SMD:R_0402_1005Metric | R2, R3, R4, R12, R16, R17 |
| 5 | 1k | Resistor_SMD:R_0402_1005Metric | R1, R7, R11, R13, R15 |
| 4 | TestPoint | TestPoint:TestPoint_Pad_D1.0mm | TP1, TP2, TP3, TP4 |
| 3 | 1uF | Capacitor_SMD:C_0402_1005Metric | C7, C11, C12 |
| 2 | 10uF | Capacitor_SMD:C_0402_1005Metric | C8, C10 |
| 2 | 12pF | Capacitor_SMD:C_0402_1005Metric | C5, C6 |
| 2 | 1M | Resistor_SMD:R_0402_1005Metric | R5, R6 |
| 2 | XL-1608UGC-04 | LED_GREEN:LED0603-RD_GREEN | LED3, STBY1 |
| 1 | 10 | Resistor_SMD:R_0402_1005Metric | R14 |
| 1 | 100 | Resistor_SMD:R_0402_1005Metric | R10 |
| 1 | 100k | Resistor_SMD:R_0402_1005Metric | R18 |
| 1 | 1N5819HW-7-F | SCHOTTKY_DIODE:SOD-123_L2.7-W1.6-LS3.7-RD | D1 |
| 1 | 2.2k | Resistor_SMD:R_0402_1005Metric | R8 |
| 1 | 22uF | Capacitor_SMD:C_0402_1005Metric | C4 |
| 1 | 6k | Resistor_SMD:R_0402_1005Metric | R9 |
| 1 | AFC01-S18FCA-00 | SCREENCON_FPC18P:FPC-SMD_18P-P0.50_JS_AFC01-S18FCA-00 | X2 |
| 1 | AO3401A | MOSFET_SWITCH:SOT-23_L2.9-W1.3-P1.90-LS2.4-BR | Q3 |
| 1 | AP2112K-3.3TRG1 | LDO_3V3:SOT-25-5_L2.9-W1.6-P0.95-LS2.8-BL | U3 |
| 1 | DW01A_C351410 | BATPROT_DW01A:SOT-23-6_L2.9-W1.6-P0.95-LS2.8-BL | U5 |
| 1 | ESP32-S3-WROOM-1 | ESP32_C2913202:WIRELM-SMD_ESP32-S3-WROOM-1 | U1 |
| 1 | FS8205A_C908265 | BATPROT_FS8205A:SOT-23-6_L2.9-W1.6-P0.95-LS2.8-BR | Q1 |
| 1 | KT-0603R | LED_RED:LED-SMD_L1.6-W0.8-R-RD | CHRG1 |
| 1 | LSM6DS3TR-C | IMU_LSM6DS3:LGA-14_L3.0-W2.5-P0.50-TL | U2 |
| 1 | MICRO5.9MMUSB | MICRO_USB:MICRO-USB-SMD_5P-P0.65-H-F_MICRO5.9MMUSB | USB1 |
| 1 | Q13FC1350000400 | RTC_CLOCK:FC-135R_L3.2-W1.5 | X1 |
| 1 | SS8050_C916392 | NPN_TRANSISTOR:SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR | Q2 |
| 1 | TMP112BIDRLR_C3019123 | TEMP_TMP112:SOT-563_L1.6-W1.2-P0.50-LS1.6-BR | U7 |
| 1 | TP4056_C725790 | CHARGER_TP4056:ESOP-8_L4.9-W3.9-P1.27-LS6.0-BL-EP | U4 |
| 1 | WAFER-PH2.0-2PWZ | BATTERYCON_2P:CONN-TH_2P-P2.00_GP01-2001WR-2P | U9 |
| 1 | YZA-009 | PUSH_BUTTON:SW-SMD_YZA-009 | U8 |
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Questions
How big is the Smartwatch PCB?
It measures 32.4 × 40.2 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Smartwatch use?
55 parts, built around the ESP32-S3-WROOM-1-N16R8, TMP112BIDRLR(UMW), AP2112K-3.3TRG1 and DW01A. 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 Smartwatch KiCad files?
From the Pedro-Seixas/Smartwatch repository on GitHub, at the commit this page was made from: the board is HW/smartwatch.kicad_pcb and its schematic HW/connectors.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Smartwatch 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).