2 layers28.9 × 20.5 mm
2 layers50 × 40 mm
Timer board
Dominik-Workshop/lap-timerLap timer, EKA 2 sem PWR
- Size
- 50 × 40 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 70
- Nets
- 76
- Pads
- 238
- Tracks, vias
- 281, 69
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 13 Apr 2025
- Updated
- 27 Mar 2026
Overview
Timer board is an open-source printed circuit board by Dominik-Workshop, from the Dominik-Workshop/lap-timer repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 50 × 40 mm with 70 parts on 76 nets, routed with 281 tracks and 69 vias.
It is built around the STM32F411RET6, AMS1117-3.3 and TSSP58038, with the CL05B104KB54PNC, KMR211NGLFS and KT-0603R among its other parts. Its parts include 18 capacitors, 12 resistors, 6 diodes, 4 switches and 3 ICs. It belongs with the STM32 boards of this library.
Main components
12
STM32F411RET6
LQFP-64(10x10)-40℃~+85℃ 1.7V~3.6V 100MHz 128KB 12bit 32 Bit 50 512KB ARM Cortex-M4 Built-in FLASH LQFP-64(10x10) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
AMS1117-3.3
SOT-223-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
TSSP58038
SIP-3-2.54mm-25℃~+85℃ 10mW 2.5V~5.5V 25m 38kHz 700uA ±45° SIP-3-2.54mm Infrared Remote Receiver (IRM) ROHSVishay IntertechnologyInfrared Remote Receiver (IRM)
CL05B104KB54PNC
0402100nF 50V X7R ±10% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
KMR211NGLFS
SMD-40℃~+85℃ 1.2N 1.9mm 2.8mm 32V 4.6mm 50mA Gull Wing Round Button SPST-NO Surface Mount,Vertical SMD Tactile Switches ROHSC&KTactile Switches
KT-0603R
0603-40℃~+85℃ 1.6mm x 0.8mm square LED 1.8V~2.4V 120° 20mA 300mcd 40mW 615nm~630nm 645nm Discrete Diode Red Water Clear 0603 LED Indication - Discrete ROHSHubei KENTO ElecLED Indication - Discrete0402CG330J500NT
040233pF 50V C0G ±5% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSGuangdong Fenghua Advanced Tech (FH)Multilayer Ceramic Capacitors MLCC - SMD/SMT
1N4148WS-AU_R1_000A1
SOD-323-55℃~+150℃ 1 Independent 1.25V@150mA 2.5uA@75V 200mA 250mW 4A 4ns 75V SOD-323 Switching Diodes ROHSPANJIT InternationalSwitching Diodes
PJ-342
SMD-30℃~+70℃ 3.5mm Headphone Jack 30V 500mA Copper Gold SMD Audio Connectors ROHSSHOU HANAudio Connectors (Headphones)
N096-2864KSWEG01-H30
--40℃~+85℃ 0.96 1.65V~3.3V 120cd/m2 128x64 21.744x10.864mm I2C、SPI Passive (PMOLED) SSD1306 chip White - OLED Display ROHSNewvisioOLED Display
PESD5Z5.0-N
SOD-52315A 18V 250W@8/20us 500nA 5V 6V 80pF ESD IEC 61000-4-2、IEC 61000-4-5、IEC 61000-4-4 Single-channel Unidirectional SOD-523 ESD and Surge Protection (TVS/ESD) ROHSBORNESD And Surge Protection (TVS/ESD)
TPD2E2U06DCKR-TP
SOT-323MOSFETsTECH PUBLIC
README
README.mdLap Timer
Overview
Compact and portable lap timer, capable of measuring time on:
- Closed-loop tracks (1-gate mode)
- Start/finish tracks (2-gate mode)
Infrared light barriers are used as optical triggers to detect when an object crosses the start or finish line.
Key Features
- High accuracy using STM32 hardware timers
- OLED display for showing lap times
- Two operating modes: 1-gate or 2-gate
- Modulated IR system (38 kHz) for ambient light immunity
Project Status
Design: ✅ --> Fabrication & Assembly: ✅ --> Bring-up: ✅
Electronics
Simplified arhitecture of the Lap Timer is shown on the block diagram bellow:
This project contains 3 custom PCBs:
- Timer board: main PCB of the system, responsible for time measurement and displaying results
- Transmitter board: generates the modulated IR light beam for the optical barrier
- Receiver board: (used only in 2-gate mode) detects the IR signal and triggers the timer
Mechanical
Each board has a custom-designed 3D printed enclosure.
Used Tools
- KiCad - Schematic and PCB design
- Autodesk Fusion 360 - 3D modeling
- STM32CubeIDE - STM32 firmware development (build/flash/debug)
Authors
- Dominik Pluta:
- Responsibility: Timer board
- Mateusz Gwioździk:
- Responsibility: Transmitter board
- Radek Mierzwa:
- Responsibility: Receiver board
Parts
70| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | C-100n-0402 | DW-footprints:C_0402_1005Metric | C1, C4, C9, C11, C12, C13, C14 |
| 7 | R-5k1-0402 | DW-footprints:R_0402_1005Metric | R2, R3, R5, R9, R10, R11, R12 |
| 5 | C-4u7-0402 | DW-footprints:C_0402_1005Metric | C2, C3, C7, C15, C16 |
| 4 | SW_KMR211NGLFS | DW-footprints:SW_KMR211NGLFS | SW1, SW2, SW3, SW4 |
| 4 | TP_SMD_1mm | DW-footprints:TP_SMD_1mm | TP1, TP2, TP3, TP4 |
| 3 | C-1u-0402 | DW-footprints:C_0402_1005Metric | C6, C8, C17 |
| 3 | LED-R-0603_KT-0603R | DW-footprints:LED_0603_1608Metric_R | D3, D4, D5 |
| 3 | R-1k-0402 | DW-footprints:R_0402_1005Metric | R4, R7, R8 |
| 2 | C-33p-0402 | DW-footprints:C_0402_1005Metric | C5, C18 |
| 1 | 1N4148WS-AU | DW-footprints:D_SOD-323F | D6 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U3 |
| 1 | C-2u2-0402 | DW-footprints:C_0402_1005Metric | C10 |
| 1 | G*** | kibuzzard-68E6B152 | kibuzzard-68E6B152 |
| 1 | G*** | kibuzzard-690B1D8E | kibuzzard-690B1D8E |
| 1 | G*** | kibuzzard-68E6B0E6 | kibuzzard-68E6B0E6 |
| 1 | G*** | kibuzzard-690B1DCB | kibuzzard-690B1DCB |
| 1 | G*** | kibuzzard-69109536 | kibuzzard-69109536 |
| 1 | G*** | kibuzzard-69109507 | kibuzzard-69109507 |
| 1 | G*** | kibuzzard-68E6B138 | kibuzzard-68E6B138 |
| 1 | G*** | kibuzzard-691094F6 | kibuzzard-691094F6 |
| 1 | G*** | kibuzzard-68E6B182 | kibuzzard-68E6B182 |
| 1 | G*** | kibuzzard-68E6B17C | kibuzzard-68E6B17C |
| 1 | G*** | kibuzzard-690B1DD3 | kibuzzard-690B1DD3 |
| 1 | G*** | kibuzzard-68FD2D82 | kibuzzard-68FD2D82 |
| 1 | G*** | kibuzzard-690B8D6F | kibuzzard-690B8D6F |
| 1 | G*** | kibuzzard-690B1DD8 | kibuzzard-690B1DD8 |
| 1 | Jack_PJ-342 | DW-footprints:Jack_PJ-342 | J2 |
| 1 | N096-2864KSWEG01-H30 | DW-footprints:N096-2864KSWEG01-H30 | DISP1 |
| 1 | PESD5Z5 | DW-footprints:D_SOD-523 | D1 |
| 1 | Programming connector | DW-footprints:Custom-programming-connector-1x6_P1.27mm | J11 |
| 1 | R-330r-0402 | DW-footprints:R_0402_1005Metric | R1 |
| 1 | R-390k-0402 | DW-footprints:R_0402_1005Metric | R6 |
| 1 | STM32F411RET6 | DW-footprints:LQFP-64_10x10mm_P0.5mm | U1 |
| 1 | TPD2E2U06DCKR | DW-footprints:SOT-323 | D2 |
| 1 | TSSP58038 | OptoDevice:Vishay_MINICAST-3Pin | U2 |
| 1 | USB-C_USB-310F-B-SU | DW-footprints:USB-C-Receptacle_USB-310-B-SU | J1 |
| 1 | X322512MSB4SI | DW-footprints:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
The 66 most common of 70 parts.
Questions
How big is the Timer board PCB?
It measures 50 × 40 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Timer board use?
70 parts, built around the STM32F411RET6, AMS1117-3.3, TSSP58038 and CL05B104KB54PNC. 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 Timer board KiCad files?
From the Dominik-Workshop/lap-timer repository on GitHub, at the commit this page was made from: the board is pcb/timer-board/timer-board.kicad_pcb and its schematic pcb/receiver-board/receiver-board.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Timer board 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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