2 layers45.5 × 52.5 mm
4 layers34.5 × 39 mm
Epd watch
andr00d/epd_watch18epd watch project
- Size
- 34.5 × 39 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 63
- Nets
- 74
- Pads
- 247
- Tracks, vias
- 451, 110
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 11 Sep 2024
- Updated
- 30 Oct 2026
Overview
Epd watch is an open-source printed circuit board by andr00d, from the andr00d/epd_watch repository on GitHub, published under the MIT licence. It is a 4-layer board of 34.5 × 39 mm with 63 parts on 74 nets, routed with 451 tracks and 110 vias.
It is built around the DS3231MZ/V+, LM66100DCK and TP4057, with the 1N5819WS, SI1308EDL and AO3401A among its other parts. Its parts include 28 capacitors, 8 resistors, 5 ICs, 5 inductors and 3 diodes. It belongs with the wearables boards and the nRF52 and nRF5x boards of this library.
Main components
8
DS3231MZ/V+
SOIC-8-40℃~+85℃ 2.3V~5.5V Built-in I2C Temperature compensation、Backup power management and battery charging、Alarm function、Locking and tamper-proof、Periodic interrupt output SOIC-8 Real Time Clocks ROHSMaxim Integrated (Analog Devices)Real Time Clocks
LM66100DCK
SC-70-6-40℃~+125℃ 1 1.5A 1.5V~5.5V 150nA 95mΩ Integrated FET Reverse current blocking、Reverse polarity protection、With enable SC-70-6 ORing Controllers ROHSTexas InstrumentsPower Distribution Switches
TP4057
SOT-23-6-40℃~+85℃ 1 25uA 4.24V 4V~6.5V Charging IC Lithium Battery Not supported SOT-23-6 Battery Management ROHSTECH PUBLICBattery Management
1N5819WS
SOD-3231 Independent 1A 25A 40V 500uA@40V 600mV@1A SOD-323 Schottky Diodes ROHSGuangdong HottechSchottky Diodes
SI1308EDL
SC-70-3-55℃~+150℃ 1 N-channel 1.4nC@10V 1.5A 1.5V 105pF 11pF 132mΩ@10V 23pF 30V 400mW N-Channel SOT-323 MOSFETs ROHSVishay IntertechnologyMOSFETs
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
FUET-4020
SMD,4x4mm-20℃~+70℃ 2.5mm 2V~4V 3V 4kHz 4mm 4mm 65dB 90mA Electromagnetic Passive (Externally Driven) SMD,4x4mm Buzzers ROHSFUETBuzzers
KH-3216-A35
1206-40℃~+85℃ 1.2mm 1.6mm 100MHz 2 2.45GHz 3.2mm 5.19dBi 50Ω Ceramic Antenna 1206 Antennas ROHSShenzhen Kinghelm ElecAntennas
README
README.mdepd watch
A low power epaper smartwatch running on an NRF52832.
It has the basic functionalities like telling time, a stopwatch, and an alarm. But also has some fun features like snake.
hardware
The kicad files for both the charger and the watch are in the hardware folder. The components in the watch already include LCSC values to order from JLCPCB, but its good to check and make sure every component is still available. Several components will also need to be rotated or moved a bit to ensure correct placement.
Several extra components are needed, for the display, the GDEW0154M09 is used. The cutout in the PCB is the perfect size for a 202040/202030 battery if you want the biggest batttery possible, but a smaller battery makes soldering easier.
The charger board is a simple PCB to easily connect 4 pogo pins to a pi pico which is flashed with debugprobe. Pogo pins of about 6mm should work best.
In the 3D_models folder are all the stl files needed to print the cases for both the charger and the watch. To attach the buttons, stick a small bit of tape to the inside of the case and attach the buttons to that, use a bit of glue for a stronger connection. The case for the watch should be able to be made watertight if filled with silicon, but this has not been tested yet.
running on the watch
A few steps are needed to be able to compile and run the code on the watch. running the following commands installs cargo embed and the correct target:
sudo apt install build-essential
rustup target add thumbv7em-none-eabihf
rustup component add llvm-tools
cargo install cargo-binutils
curl --proto '=https' --tlsv1.2 -LsSf https://github.com/probe-rs/probe-rs/releases/latest/download/probe-rs-tools-installer.sh | sh
After this is finished, just place the watch on the charger and run cargo embed to flash the watch. if it says it cannot find the programmer, the udev rules might be annoying, follow the instructions on this page, and make sure the watch is making good connection with the programmer.
running on your pc
There is a pc_test folder that allows additions to the watch to be tested a bit more easily than having to constantly wait for the watch to be programmed. simply go into the pc_test folder, type cargo run and you can test if everything is as you expect.
Parts
63| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | 4.7uf/25V | Capacitor_SMD:C_0402_1005Metric | C7, C8, C12, C16, C18, C20, C23, C24 |
| 6 | 10K | Resistor_SMD:R_0402_1005Metric | R1, R2, R3, R5, R7, R8 |
| 5 | 1.0uF/50V | Capacitor_SMD:C_0402_1005Metric | C4, C17, C19, C21, C22 |
| 4 | 100nf | Capacitor_SMD:C_0402_1005Metric | C5, C9, C10, C11 |
| 4 | 12pf | Capacitor_SMD:C_0402_1005Metric | C1, C2, C25, C26 |
| 3 | 1N5819WS | Diode_SMD:D_SOD-323 | D4, D5, D6 |
| 3 | 4.7uF | Capacitor_SMD:C_0402_1005Metric | C14, C27, C28 |
| 2 | 1.0uF | Capacitor_SMD:C_0402_1005Metric | C13, C15 |
| 2 | Si1308EDL | Package_TO_SOT_SMD:SOT-323_SC-70 | Q1, Q3 |
| 1 | 0.47Ω | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 0.8pf | Capacitor_SMD:C_0402_1005Metric | C3 |
| 1 | 1.8nH | Inductor_SMD:L_0402_1005Metric | L1 |
| 1 | 100pf | Capacitor_SMD:C_0402_1005Metric | C6 |
| 1 | 10uH | Inductor_SMD:L_0805_2012Metric | L4 |
| 1 | 10uH 1A | Inductor_SMD:L_0805_2012Metric | L5 |
| 1 | 15nH | Inductor_SMD:L_0402_1005Metric | L3 |
| 1 | 3.7v | epd_watch:batt_con | BT1 |
| 1 | 3.9nH | Inductor_SMD:L_0402_1005Metric | L2 |
| 1 | 32.768khz | epd_watch:SMD3215 | Y2 |
| 1 | 32Mhz | Crystal:Crystal_SMD_2016-4Pin_2.0x1.6mm | Y1 |
| 1 | 3Ω | Resistor_SMD:R_0402_1005Metric | R6 |
| 1 | AO3401A | Package_TO_SOT_SMD:SOT-23 | Q2 |
| 1 | BTN_DOWN | epd_watch:TS-1010A-B | SW3 |
| 1 | BTN_MIDDLE | epd_watch:TS-1010A-B | SW2 |
| 1 | BTN_UP | epd_watch:TS-1010A-B | SW1 |
| 1 | DS3231MZ | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | FPC | epd_watch:FPC-05F-24PH15 | P1 |
| 1 | FUET-4020 | epd_watch:FUET-4020 | BZ1 |
| 1 | GPIO | epd_watch:gpio_conn | J2 |
| 1 | KH-3216-A35 | epd_watch:KH-3216-A35 | AE1 |
| 1 | LM66100DCK | Package_TO_SOT_SMD:SOT-363_SC-70-6 | U5 |
| 1 | SWD_interface | epd_watch:pogo_conn | J1 |
| 1 | TP4057 | Package_TO_SOT_SMD:SOT-23-6 | U3 |
| 1 | XC6206PxxxMR | Package_TO_SOT_SMD:SOT-23-3 | U2 |
| 1 | nRF52832-QFxx | Package_DFN_QFN:QFN-48-1EP_6x6mm_P0.4mm_EP4.6x4.6mm | U1 |
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Questions
How big is the Epd watch PCB?
It measures 34.5 × 39 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Epd watch use?
63 parts, built around the DS3231MZ/V+, LM66100DCK, TP4057 and 1N5819WS. 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 Epd watch KiCad files?
From the andr00d/epd_watch repository on GitHub, at the commit this page was made from: the board is hardware/watch/epd_watch.kicad_pcb and its schematic hardware/charger/watch_charger.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Epd 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).