2 layers60 × 30 mm
Controller
google/mozc-devices
Circuit diagrams and firmware source code for Gboard DIY keyboards
11 parts3kApache-2.0
2 layers34.8 × 24 mm
Clock
grimsteel/clock1(temp name): Working 4-person HP Weasley Clock | Uses Home Assistant location information
- Size
- 34.8 × 24 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 11
- Nets
- 25
- Pads
- 54
- Tracks, vias
- 48, 1
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 21 Mar 2026
- Updated
- 28 Apr 2026
Overview
Clock is an open-source printed circuit board by grimsteel, from the grimsteel/clock repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 34.8 × 24 mm with 11 parts on 25 nets, routed with 48 tracks and 1 via.
Its parts include 4 connectors, 2 resistors, 2 diodes and 1 IC. It belongs with the lEDs and displays boards and the ESP32 and RISC-V boards of this library.
README
README.mdClock
Working 4-person location clock. Uses Home Assistant location zone information.
Usage
Assembly
- 3D-print and laser cut the necessary components (see the
cad/folder for a parts list and Onshape link) - Solder the ESP32 and pin headers onto the PCB.
- Assemble the back frame (back, PCB, standoffs, and servo mount)
- Attach the servos to the servo mount
- Add the shafts, placing PTFE washers in between
- Attach the front frame
- Attach the front decorations and the hands
Using it
- Install one of the provided firmwares, configuring the people/locations as necessary (see
firmware/README.md) - Profit. This does rely on accurate zone information in Home Assistant.
Technical Information
Structure
More information can be found in the cad/ folder. The clock consists of a laser cut front and back frame.
Each hand is controlled by a servo with a 2:1 gear ratio. The servos and gears are mouted on a 3d-printed frame, which is fastened to the back frame.
The hands are attached to four concentric shafs, each terminating at a different height. This is part of the reason the clock is so thick.
The front includes 4 possible mounting spots for LEDs.
PCB
The PCB consists of a surface mounted ESP32 C3 Supermini with connections for the 4 servos and 2 LEDs:
| Schematic | 3D render |
|---|---|
 |  |
| Front | Back |
 |  |
Firmware
Two firmwares are provided: an ESPHome and a native ESP-IDF firmware. More information can be found in the firmware/ folder.
BOM
| Description | Link | Per-unit price | Quantity | Total price | Running price w/ tax |
|---|---|---|---|---|---|
| CAD components | https://cad.onshape.com/documents/5b8ef3e45edb03dc1124a4e9 | $0.00 | 1 | $0.00 | $0.00 |
| PCB | https://oshpark.com | $6.45 | 1 | $6.45 | $7.01 |
| ESP32-C3 Supermini | https://www.aliexpress.us/item/3256807292829704.html | $2.70 | 1 | $2.70 | $9.94 |
| MG90s Micro Servo (5 pack) | https://www.aliexpress.us/item/3256808303872992.html | $9.88 | 1 | $9.88 | $20.68 |
Parts
11| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | Conn_01x03_Pin | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J1, J2, J3, J4 |
| 2 | 1k | Resistor_THT:R_Axial_DIN0204_L3.6mm_D1.6mm_P7.62mm_Horizontal | R1, R2 |
| 2 | LED | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm | D1, D2 |
| 2 | MountingHole | MountingHole:MountingHole_3.2mm_M3 | H1, H2 |
| 1 | ESP32-C3-SuperMini | custom:ESP32-C3-SuperMini | U1 |
Questions
How big is the Clock PCB?
It measures 34.8 × 24 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Clock use?
11 parts. 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 Clock KiCad files?
From the grimsteel/clock repository on GitHub, at the commit this page was made from: the board is pcb/clock.kicad_pcb and its schematic pcb/clock.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Clock design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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