

Boluder clock replacement
This project provides the source code and design files for the Boulder Clock Replacement Board, designed as a direct drop-in replacement for the original Boulder Clock hardware.
- Size
- 150.3 × 47.5 mm
- Copper layers
- 4
- Thickness
- 1.61 mm
- Parts
- 225
- Nets
- 272
- Pads
- 770
- Tracks, vias
- 1,876, 223
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 10 Mar 2025
- Updated
- 9 Oct 2025
Overview
Boluder clock replacement is an open-source printed circuit board by mickdassive, from the mickdassive/boulder_clock_replacent_bord repository on GitHub. It is a 4-layer board of 150.3 × 47.5 mm with 225 parts on 272 nets, routed with 1,876 tracks and 223 vias.
It is built around the ESP-12F, HV9150K6-G and TPS63031DSKR, with the CD4028BNSR, PI4IOE5V6416LEX and BSS127H6327XTSA2 among its other parts. Its parts include 88 resistors, 61 transistors, 30 capacitors, 12 ICs and 3 switches. It belongs with the lEDs and displays boards and the ESP8266 boards of this library.
Main components
8ESP-12F
SMD,24x16mm-40℃~+85℃ -96dBm 15dBm 2.4GHz 3.3V 375mA 55mA PCB UART WIFI4 SMD,24x16mm WiFi Modules ROHSDOITWiFi ModulesHV9150K6-G
TQFN-16-EP(3x3)-25℃~+125℃ 2.7V~4.5V 5V~12.6V boost converter TQFN-16-EP(3x3) Charge Pumps ROHSMicrochip TechnologyCharge PumpsTPS63031DSKR
SON-10-EP(2.5x2.5)-40℃~+125℃@(TJ) 1 1.8V~5.5V 2.4MHz 25uA 3.3V 900mA Buck-Boost Buck-Boost Built-in Fixed Yes SON-10-EP(2.5x2.5) DC-DC Converters ROHSTexas InstrumentsDC-DC ConvertersCD4028BNSR
SO-16-208mil-55℃~+125℃ 0.04uA、0.04uA、0.04uA、0.08uA 3V~18V 510uA、1.3mA、1.6mA、3.4mA 510uA、1.3mA、3.4mA 60ns@15V,50pF CD4000 Decoder Level shifting Single Supply SO-16-208mil Signal Switches, Multiplexers, Decoders ROHSTexas InstrumentsSignal Switches, Multiplexers, DecodersPI4IOE5V6416LEX
TSSOP-24-40℃~+85℃ 1.5uA 1.65V~5.5V 10mA 16 25mA 400kHz I2C Interrupt Output Push-Pull、Open-drain Reset function、Cascading and address extension、IO level configurable TSSOP-24 I/O Expanders ROHSDiodes IncorporatedI/O ExpandersBSS127H6327XTSA2
SOT-231 N-channel 1.5pF 1nC@10V 2.6V 21mA 28pF 3pF 500mW 500Ω@10V 600V N-Channel SOT-23 MOSFETs ROHSInfineon TechnologiesMOSFETsFQD12N20LTM-F085P
TO-252AA-55℃~+150℃ 1 N-channel 2.5W、55W 200V 2V TO-252AA MOSFETs ROHSonsemiMOSFETsUSB4515-GF-A
SMD-30℃~+85℃ 1 3A 48V 6P Black Female Surface Mount, Right Angle Type-C SMD USB Connectors ROHSGlobal Connector Technology (GCT)USB Connectors
README
README.mdBoulder Clock Replacement Board
This project provides the source code and design files for the Boulder Clock Replacement Board, designed as a direct drop-in replacement for the original Boulder Clock hardware. The board is fully compatible with existing clock circuitry—no additional wiring or modifications are required.
Features
- Drop-in replacement for Boulder Clock boards—no extra wiring needed
- Open-source hardware and software design (GPLv3 license)
- Improved time accuracy
- WiFi configuration via web interface (WiFi Manager)
- Adjustable GMT offset, DST settings, and 12/24 hour mode
- Easy-to-follow assembly instructions
Getting Started
Prerequisites
- Basic knowledge of electronics and soldering
- Appropriate tools for PCB assembly
- PlatformIO installed for firmware upload
Installation
-
Clone the Repository
bash git clone https://github.com/mickdassive/boulder_clock_replacent_bord.git cd boulder_clock_replacent_bord -
Review Design Files
- Check the
hardware/orpcb/directory for PCB layout and schematics. - Review the
firmware/directory for microcontroller code.
- Check the
-
Build and Assemble
- Order the PCB using the provided Gerber files.
- Source and solder components as listed in the bill of materials (BOM).
-
Upload Firmware Using PlatformIO
-
Open the project in PlatformIO IDE (recommended for VS Code).
-
Connect your microcontroller board to your computer via USB.
-
In PlatformIO, select the correct environment for your board (see
platformio.ini). -
Build and upload the firmware:
text pio run --target uploadOr use the "Upload" button in the PlatformIO IDE.
-
The firmware is pre-configured for the Boulder Clock Replacement Board. No code changes or configuration should be necessary for standard operation.
-
WiFi Manager Configuration
The board features a built-in WiFi Manager interface for easy configuration of time and connectivity settings:
-
Initial Setup
- After powering on the board, if no WiFi credentials are stored, it will automatically start in WiFi Access Point mode.
- Connect to the WiFi network broadcast by the board (SSID will be " Boulder Clock fwv x.x" or similar).
-
Access the Web Interface
- Open a web browser and navigate to
192.168.4.1to access the configuration portal.
- Open a web browser and navigate to
-
Configure WiFi and Clock Settings
- Enter your local WiFi credentials.
- Set the following options in the web interface:
- GMT Offset: Adjust the clock’s time zone offset from GMT (e.g., +1, -5, etc.).
- 12/24 Hour Mode: Choose between 12-hour (AM/PM) or 24-hour display.
- Daylight Saving Time (DST): Enable or disable automatic DST adjustment.
-
Save Settings
- Save your changes and allow the board to reboot. It will connect to your WiFi and keep time according to your chosen settings.
Usage
- Install the assembled board in place of the original Boulder Clock board.
- No extra wiring is needed—simply drop in as a replacement.
- Power on and configure settings via the WiFi Manager if needed.
Repository Structure
hardware/ # PCB schematics, layouts, and Gerber files
firmware/ # PlatformIO project, microcontroller code
platformio.ini # PlatformIO configuration file
LICENSE # GPLv3 license information
README.md # This fileContributing
Contributions are welcome! If you have suggestions, improvements, or bug fixes, please submit a pull request or open an issue.
License
This project is licensed under the GNU General Public License v3.0. See the LICENSE file for details.
Acknowledgments
- Inspired by the original Boulder Clock hardware
For additional help or questions, please open an issue in this repository.
Parts
225| Qty | Value | Footprint | References |
|---|---|---|---|
| 60 | 3K3 | Resistor_SMD:R_0603_1608Metric | R14, R15, R16, R17, R18, R20, R21, R22, R23, R24, R25, R26, R27, R28, R29, R31 +44 |
| 60 | BSS127H6327XTSA2 | Package_TO_SOT_SMD:SOT-23 | Q1, Q2, Q10, Q11, Q12, Q13, Q14, Q15, Q16, Q17, Q18, Q19, Q20, Q22, Q23, Q24 +44 |
| 15 | 0uF1 | Capacitor_SMD:C_0603_1608Metric | C3, C4, C6, C7, C8, C9, C12, C13, C14, C16, C19, C21, C23, C24, C27 |
| 10 | 10K | Resistor_SMD:R_0603_1608Metric | R1, R2, R4, R5, R6, R7, R8, R11, R12, R13 |
| 10 | 10uF | Capacitor_SMD:C_0603_1608Metric | C1, C2, C10, C11, C15, C17, C18, C20, C22, C29 |
| 10 | TestPoint | TestPoint:TestPoint_Pad_D1.0mm | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10 |
| 6 | 80K | Resistor_SMD:R_0603_1608Metric | R19, R30, R50, R61, R72, R83 |
| 6 | CD4028BNSR | Package_SO:SOP-16_4.4x10.4mm_P1.27mm | U4, U5, U7, U8, U9, U10 |
| 6 | ~ | boulder:boulder nixie | NT1, NT2, NT3, NT4, NT5, NT6 |
| 3 | 2K2 | Resistor_SMD:R_0603_1608Metric | R9, R10, R43 |
| 3 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5 | H1, H2, H3 |
| 2 | 1K | Resistor_SMD:R_0603_1608Metric | R3, R39 |
| 2 | 5K1 | Resistor_SMD:R_0603_1608Metric | R37, R38 |
| 2 | PI4IOE5V6416LEX | boulder:TSSOP-24_4.4x7.8mm_P0.65mm | U1, U2 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric | R42 |
| 1 | 1uF | Capacitor_SMD:C_0603_1608Metric | C26 |
| 1 | 22uF | Capacitor_SMD:C_0603_1608Metric | C5 |
| 1 | 250BXC22MEFC10X16 22uF | Capacitor_THT:CP_Radial_D8.0mm_P5.00mm | C28 |
| 1 | 32KHz768 | boulder:XTAL_SC32S-7PF20PPM_EPS | Y1 |
| 1 | 330R | Resistor_SMD:R_0603_1608Metric | R36 |
| 1 | 36-2997-ND | boulder:2997_KEY | BT1 |
| 1 | 47K | Resistor_SMD:R_0603_1608Metric | R41 |
| 1 | 4uF7 | Capacitor_SMD:C_0603_1608Metric | C25 |
| 1 | BRL3225T1R5M 1uH5 | Inductor_SMD:L_1210_3225Metric | L1 |
| 1 | C1206X104K251T 0uF1 | Capacitor_SMD:C_1206_3216Metric | C30 |
| 1 | ESP-12F | RF_Module:ESP-12E | U6 |
| 1 | FQD12N20LTM-F085P | Package_TO_SOT_SMD:TO-252-2 | Q21 |
| 1 | G*** | kibuzzard-67CF4B2F | kibuzzard-67CF4B2F |
| 1 | G*** | kibuzzard-67CF4A67 | kibuzzard-67CF4A67 |
| 1 | G*** | kibuzzard-67CF4A53 | kibuzzard-67CF4A53 |
| 1 | G*** | kibuzzard-67CF4A70 | kibuzzard-67CF4A70 |
| 1 | HV9150 | Package_DFN_QFN:QFN-16-1EP_3x3mm_P0.5mm_EP1.7x1.7mm | U11 |
| 1 | MINUS | Button_Switch_THT:SW_Tactile_SKHH_Angled | SW3 |
| 1 | NHP140SFT3G | boulder:NHP140SF-D | D1 |
| 1 | NS10145T470MNVV 47uH | Inductor_SMD:L_Taiyo-Yuden_NR-10050_9.8x10.0mm | L2 |
| 1 | PCF8523TK/1,118 | Package_SON:HVSON-8-1EP_4x4mm_P0.8mm_EP2.2x3.1mm | U3 |
| 1 | PLUS | Button_Switch_THT:SW_Tactile_SKHH_Angled | SW2 |
| 1 | PROG_PORT | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J1 |
| 1 | PVG3A102C01R00 1K | boulder:POT_PVG3A_BRN | R40 |
| 1 | PVG3A502C01R00 5K | boulder:POT_PVG3A_BRN | R44 |
| 1 | SET | Button_Switch_THT:SW_Tactile_SKHH_Angled | SW1 |
| 1 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1 |
| 1 | TPS63031DSKR | boulder:TPS63031DSKR | U12 |
| 1 | USB4515-GF-A | boulder:USB4515-GF-A_GCT | J2 |
Similar boards
- 2 layers95 × 98.5 mm

- 2 layers305.2 × 234.8 mm

- 2 layers24 × 28.6 mm

- 2 layers25.4 × 43.2 mm

- 4 layers30 × 20 mm

Swd switch
alvarop/debugotron
Debugotron is a collection of debugging/automation tools I've wanted in the past but didn't have access to. Currently, the tools include:
28 parts52BSD-3-Clause - 4 layers

Usbc car module
mickdassive/usbc_car_module
This project is a USB 3.1x1 hub designed with KiCad 8.0 and developed with PlatformIO. It features two USB-C ports (one downstream and one upstream) capable of delivering up to 100W power, along with four regular…
408 parts3GPL-3.0 - 2 layers189 × 92.3 mm

- 4 layers100 × 100 mm

SCARA V1
ejaduwari/Sensor-Actuator-Control-PCB
STM32F103C8 carrier board controlling 6 stepper motors, servos, limit switches, and IO expanders with UART, SPI, and I2C interfaces.
106 parts
Questions
How big is the Boluder clock replacement PCB?
It measures 150.3 × 47.5 mm and has 4 copper layers, 1.61 mm thick.
What parts does the Boluder clock replacement use?
225 parts, built around the ESP-12F, HV9150K6-G, TPS63031DSKR and CD4028BNSR. 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 Boluder clock replacement KiCad files?
From the mickdassive/boulder_clock_replacent_bord repository on GitHub, at the commit this page was made from: the board is hardware/boluder clock replacement.kicad_pcb and its schematic hardware/DIGITS.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Boluder clock replacement design in my own project?
Its repository states no licence, so its author keeps all rights: ask mickdassive before reusing the design.