

EpochCounter
A counter to count the days since a specific date using an Arduino nano, DS3231 RTC and a 4-digit 7 Segment display
- Size
- 100.3 × 55.9 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 16
- Nets
- 39
- Pads
- 92
- Tracks, vias
- 413, 38
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 17 Jun 2025
- Updated
- 17 Jun 2025
Overview
EpochCounter is an open-source printed circuit board by LostInAPit, from the LostInAPit/EpochCounter repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 100.3 × 55.9 mm with 16 parts on 39 nets, routed with 413 tracks and 38 vias.
It is built around the CC56-12SRWA, DS3231MZ+ and L7805. Its parts include 6 resistors, 4 capacitors, 3 ICs and 1 connector. It belongs with the lEDs and displays boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
3CC56-12SRWA
DIP-12DIP-12 LED Segment Displays ROHSKingbrightLED Segment DisplaysDS3231MZ+
SOIC-8-40℃~+85℃ 2.3V~5.5V I2C Temperature compensation、Backup power management and battery charging、Alarm function、Periodic interrupt output SOIC-8 Real Time Clocks ROHSMaxim Integrated (Analog Devices)Real Time ClocksL7805
TO-220ST0℃~+125℃@(Tj) 1 1.2A 20V 2V@(1A) 42uV 500uA 5V 73dB@(120Hz) Fixed Positive Short Circuit Protection TO-220ST Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSOSENVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mdEpochCounter
A counter to count the days since a specific date using an Arduino nano, DS3231 RTC and a 4-digit 7 Segment display
I designed this project to be a simple, self contained display for your workspace, office or anywhere with access to wall power. The main use of the project is to count the days since a specific event, lifestyle change such as sobriety, mental health goals or really any other reason.
Parts
16| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 220 | Resistor_SMD:R_1206_3216Metric | R3, R4, R5, R6 |
| 2 | 0.1uF 50V | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C1, C2 |
| 2 | 450 | Resistor_SMD:R_1206_3216Metric | R1, R2 |
| 1 | 1072 | 1072:BAT_1072 | BT1 |
| 1 | 22uF 50V | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C4 |
| 1 | 470uF 50V | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C3 |
| 1 | Arduino_Nano_Socket | PCM_arduino-library:Arduino_Nano_Socket | A1 |
| 1 | CC56-12SRWA | Display_7Segment:CA56-12SRWA | U1 |
| 1 | DCJ200-10-A-XX-K_REVA | DCJ200-10-A-XX-K_REVA:GCT_DCJ200-10-A-XX-K_REVA | J1 |
| 1 | DS3231M | Package_SO:SOIC-16W_7.5x10.3mm_P1.27mm | U2 |
| 1 | L7805 | Package_TO_SOT_THT:TO-220-3_Vertical | U3 |
Questions
How big is the EpochCounter PCB?
It measures 100.3 × 55.9 mm and has 2 copper layers, 1.6 mm thick.
What parts does the EpochCounter use?
16 parts, built around the CC56-12SRWA, DS3231MZ+ and L7805. 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 EpochCounter KiCad files?
From the LostInAPit/EpochCounter repository on GitHub, at the commit this page was made from: the board is KiCad/EpochCounter.kicad_pcb and its schematic KiCad/EpochCounter.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the EpochCounter 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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