2 layers45.7 × 31.8 mm
LEDx16 board
tardate/LittleArduinoProjects
a collection of "Little Electronic & Arduino Projects", most involving electronics or an Arduino in one way or another!
36 parts803MIT
2 layers70.1 × 38.5 mm
A pcb design for a 7 segment clock for single sided milled pcbs
- Size
- 70.1 × 38.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 42
- Nets
- 31
- Pads
- 115
- Tracks, vias
- 729, 6
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 6 Oct 2026
- Updated
- 6 Oct 2026
Overview
ClockR1 is an open-source printed circuit board by 9a, from the 9a/single_sided_7_segment_clock repository on GitHub. It is a 2-layer board of 70.1 × 38.5 mm with 42 parts on 31 nets, routed with 729 tracks and 6 vias.
It is built around the 74HC595. Its parts include 29 diodes, 8 resistors, 2 capacitors, 2 ICs and 1 connector.
Main components
1README
README.mdSingle Sided 7 segment clock PCB (optimized for use with ESP D1 Mini/ESP-home)
A pcb design for a 7 segment clock for single sided milled pcbs. Designed with KiCad 10.
BOM (alternatives are also OK):
- 2x SN74HC595DR
- 29x 150080RS75000
- 8x 10 Ohm 0805 (or 0603)
See schematic/placement picture for assembly (diode orientation!). The through holes other than for the 5 pin connector need to be connected via jumper wires.
It is designed to be connected to a USB-C ESP8266 D1-mini with a one to one connection via jumper wires to the pins 5V GND D4 D3 D2. Since the pins expose the control pins of the shift registers any microcontroller can be adapted.
For use with ESP home in Homeassistant: The provided esp_yaml.txt can be copied when creating the device, the cnc_display.h needs to be copied into the esphome directory.
Parts
42| Qty | Value | Footprint | References |
|---|---|---|---|
| 29 | LED | LED_SMD:LED_0805_2012Metric | D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +13 |
| 8 | 100 | Resistor_SMD:R_0805_2012Metric | R1, R2, R3, R4, R5, R6, R7, R8 |
| 2 | 74HC595 | Package_SO:SO-16_3.9x9.9mm_P1.27mm | U2, U3 |
| 2 | C | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C3 |
| 1 | Conn_01x05_Pin | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J1 |
Questions
How big is the ClockR1 PCB?
It measures 70.1 × 38.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the ClockR1 use?
42 parts, built around the 74HC595. 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 ClockR1 KiCad files?
From the 9a/single_sided_7_segment_clock repository on GitHub, at the commit this page was made from: the board is clockR1.kicad_pcb and its schematic clockR1.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ClockR1 design in my own project?
Its repository states no licence, so its author keeps all rights: ask 9a before reusing the design.
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