2 layers
Encoder
byrantech/laptop
anyon_e, a highly integrated, high end, open source laptop. Attempt the impossible.
7 parts4.3kMIT
2 layers70 × 70 mm
Tetra clock
wldd22/tetra-clockA custom alarm clock loosely based on the Blare guide
- Size
- 70 × 70 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 7
- Nets
- 18
- Pads
- 38
- Tracks, vias
- 27, 0
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 10 Oct 2026
- Updated
- 6 Nov 2026
Overview
Tetra clock is an open-source printed circuit board by wldd22, from the wldd22/tetra-clock repository on GitHub. It is a 2-layer board of 70 × 70 mm with 7 parts on 18 nets, routed with 27 tracks and 0 vias.
It belongs with the lEDs and displays boards and the ESP32 boards of this library.
README
README.mdTetra Clock
A custom alarm clock loosely based on the Blare guide.
Details
PCB made using KiCAD
Firmware uses CircuitPython
This PCB is a simple alarm clock display I designed to show the date and time, and set alarms.
- Microcontroller: XIAO ESP32-S3
- Display: 0.91 inch 128x32 OLED display (SSD1306 driver)
- Sound: 3V Active Electromagnetic Buzzer
- Input: Capacitive touchpads
Features:
- ISO 8601 timestamp datetime display
- Set alarm time
- Alarm enabled toggle
- Snooze enabled toggle
About
When I saw Mitxela's Precision Clock, I was inspired to design a custom clock myself. I wanted mine to be much more compact, like something you could carry around in a pocket, but that still looked cool and worked well. I used capacitive pads because it's an easy way I've found to make button inputs that, one, don't require any extra components, and two, are as compact as possible, being just as slim as the board itself.
This project was originally made for week 1 (PCB week) of Hack Club's Half Life. The idea and some of the components used were based on the Blare guide, but the actual design and the firmware was created from scratch by me.
Setup
- Obtain hardware - Buy the components and get the PCB fabricated (gerber).
- Solder parts - Using pin headers where necessary, solder the microcontroller, buzzer, and display onto the board.
- Install CircuitPython - Use the CircuitPython guide for the XIAO ESP32S3 to install it onto the board.
- Upload firmware - Use the same guide to upload the firmware to the board.
Images
Schematic
PCB
Parts
7| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | TestPoint | Capacitive Pads:CAP_CIRCLE_PAD | TP1, TP2, TP3, TP4 |
| 1 | Buzzer | Buzzer_Beeper:Buzzer_12x9.5RM7.6 | BZ1 |
| 1 | SSD1306 I2C OLED 128x32 | SSD1306 OLED:SSD1306 I2C OLED 128x32 | DS1 |
| 1 | XIAO-ESP32-S3-DIP | Seeed Studio XIAO Series Library:XIAO-ESP32-S3-DIP | U1 |
Questions
How big is the Tetra clock PCB?
It measures 70 × 70 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Tetra clock use?
7 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 Tetra clock KiCad files?
From the wldd22/tetra-clock repository on GitHub, at the commit this page was made from: the board is pcb/tetra-clock.kicad_pcb and its schematic pcb/tetra-clock.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Tetra clock design in my own project?
Its repository states no licence, so its author keeps all rights: ask wldd22 before reusing the design.
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