4 layers90.2 × 95.9 mm
4 layers42 × 42 mm
Exa tim
hasenbanck/exa_tim6EXA_tim is a wrist watch PCB with GNSS time synchronization and e-paper display
- Size
- 42 × 42 mm
- Copper layers
- 4
- Thickness
- 1 mm
- Parts
- 53
- Nets
- 58
- Pads
- 232
- Tracks, vias
- 553, 79
- Pours
- 6
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 20 Aug 2018
- Updated
- 1 Oct 2018
Overview
Exa tim is an open-source printed circuit board by hasenbanck, from the hasenbanck/exa_tim repository on GitHub. It is a 4-layer board of 42 × 42 mm with 53 parts on 58 nets, routed with 553 tracks and 79 vias.
It is built around the CAM-M8C-0, MBR0530 and TL3305CF260QG, with the SI2333DS-T1-E3, 20021112-00010T4LF and 3034TR among its other parts. Its parts include 24 capacitors, 7 resistors, 7 diodes, 4 switches and 3 transistors. It belongs with the lEDs and displays and radio and wireless boards and the STM32 boards of this library.
Main components
7
CAM-M8C-0
SMD-31P-167dBm -40℃~+85℃ 1.6V~3.6V GPS、QZSS、BeiDou、GLONASS UART、SPI SMD-31P GNSS Modules ROHSu-bloxGNSS Modules
MBR0530
SOD-1231 Independent 30V 5.5A 500mA 550mV@500mA 80uA@30V SOD-123 Schottky Diodes ROHSJiangsu Changjing Electronics Technology (CJ)Schottky Diodes
TL3305CF260QG
SMD-4P,4.5x4.5mm-20℃~+70℃ 12V 2.6N 200,000 Cycles 4.5mm 4.5mm 50mA 7mm Gull Wing Red Round Button SPST Surface Mount,Vertical Without Bracket SMD-4P,4.5x4.5mm Tactile Switches ROHSE-SwitchTactile Switches
SI2333DS-T1-E3
SOT-23-55℃~+150℃ 1 P-Channel 1.1nF 12V 18nC@4.5V 1V 25mΩ@4.5V 300pF 390pF 4.1A 750mW P-Channel ±8V SOT-23 MOSFETs ROHSVishay IntertechnologyMOSFETs20021112-00010T4LF
弯插,P=1.27mm-55℃~+125℃ 1.27mm 1.27mm 10P 125V 1A 2 2.69mm 3.05mm 3.43mm Black Copper alloy Right Angle Square pin Tin Push-Pull,P=1.27mm Pin Headers ROHSAmphenolPin Headers
3034TR
-- Battery Snap ROHSKeystone ElectronicsBatteryConnector
FH12-24S-0.5SH(55)
SMD,P=0.5mm,卧贴-40℃~+85℃ 0.3mm 0.5mm 24P 2mm Bottom Contact Gold Hinged Lid Phosphor bronze Surface Mount, Right Angle SMD,P=0.5mm,卧贴 FFC, FPC (Flat Flexible) Connector Assemblies ROHSHirose ElectricFFC, FPC (Flat Flexible) Connector Assemblies
README
README.mdEXA_tim
EXA_tim is a wristwatch that uses GNSS for time synchronization.
Features
- 32bit STM32L0 MCU
- GNSS time synchronization (UTC)
- 1.54 inch e-paper display
- 4 buttons
- CR2032 battery
Currently we are aiming for 2-3 months of operation with one battery.
Case
The case is designed in Fusion 360 and can be viewed here: https://a360.co/2LLzCpt
A current snapshot is included in the source repository.
The case is designed to be 3D printable and uses a NATO strap.
If you want to 3D print them, you need to either use Fusion 360 or FreeCAD to export the three components as STL files.
I printed them in PLA and PETG with good results. Low warp material hightly recommended, since dimensional accuracy is key.
I designed the parts for a printer that can handle 0.1 mm clearance. If you need looser clearance, please change the Fusion 360 user variable "Clearance" for your needed value.
Firmware
The firmware uses the STM32 HAL. It can be build by either using cmake with the ARM GCC toolchain or by using Atollic TrueStudio.
For the CMAKE build, you need to provide the ARM GCC toolchain in the PATH of your system. You can choose any CMAKE target that you like to use. I personaly use ninja.
cd firmware
cmake -DCMAKE_TOOLCHAIN_FILE=arm-gcc-toolchain.cmake -G Ninja .
ninjaYou can change add a -DCMAKE_BUILD_TYPE=Debug to the CMAKE
command to produce a debug build.
Flashing
To programm the watch we are using the 10 pin 1.27mm (0.05") Cortex Debug header. You need a programmer that can programm an ARM using the SWD protocol.
A ST-Link V2 (and it's clones), a JLink (mini) or a blackmagic programmer should work fine.
We included a OpenOCD file as an example how to programm the firmware.
You can also use any available flashing software available. For example:
- OpenOCD
- STM32CubeProgrammer
- STM32 ST-Link utility
- Segger J-Link JFlash (lite)
License
The hardware components (case and PCB) are licensed under the CERN Open Hardware Licence v1.2
The software components (firmware) are licensed under GPLv3.
The pcb/packages3d files are excluded from these license.
Parts
53| Qty | Value | Footprint | References |
|---|---|---|---|
| 10 | 1uF | Capacitor_SMD:C_0603_1608Metric | C8, C15, C16, C18, C19, C20, C21, C22, C23, C24 |
| 8 | 100nF | Capacitor_SMD:C_0603_1608Metric | C4, C5, C7, C9, C10, C11, C14, C17 |
| 7 | MBR0530 | Diode_SMD:D_SOD-123 | D1, D2, D3, D4, D5, D6, D7 |
| 4 | 1M | Resistor_SMD:R_0603_1608Metric | R1, R2, R5, R6 |
| 4 | 4.7uF | Capacitor_SMD:C_0603_1608Metric | C1, C6, C12, C13 |
| 4 | TL3305CF260QG | exa_tim:TL3305 | SW1, SW2, SW3, SW4 |
| 2 | 220 | Resistor_SMD:R_0603_1608Metric | R3, R4 |
| 2 | 4pF | Capacitor_SMD:C_0603_1608Metric | C2, C3 |
| 2 | SI2333DS-T1-E3 | Package_TO_SOT_SMD:SOT-23 | Q1, Q2 |
| 1 | 20021112-00010T4LF | Connector_PinHeader_1.27mm:PinHeader_2x05_P1.27mm_Horizontal | J1 |
| 1 | 3 | Resistor_SMD:R_0603_1608Metric | R7 |
| 1 | 3034TR | exa_tim:BatteryHolder_Keystone_3034_1x20mm | BT1 |
| 1 | CAM-M8C-0 | exa_tim:LCC100P960X1400X210-31N | U2 |
| 1 | CUI_CSS-0575A-SMT | exa_tim:CUI_CSS-0575A-SMT | LS1 |
| 1 | DMN3067LW-7 | Package_TO_SOT_SMD:SOT-323_SC-70 | Q3 |
| 1 | FH12-24S-0.5SH(55) | exa_tim:Hirose_FH12-24S-0.5SH_1x24-1MP_P0.50mm_Horizontal | J2 |
| 1 | LPS4018-683MRB | exa_tim:L_Coilcraft_LPS4018 | L1 |
| 1 | ST2012SB32768B0HPWBB | exa_tim:Crystal_SMD_TXC_9HT11-2Pin_2.0x1.2mm_HandSoldering | Y1 |
| 1 | STM32L071KZUx | exa_tim:QFN-32-1EP_5x5mm_P0.5mm_EP3.45x3.45mm | U1 |
Questions
How big is the Exa tim PCB?
It measures 42 × 42 mm and has 4 copper layers, 1 mm thick.
What parts does the Exa tim use?
53 parts, built around the CAM-M8C-0, MBR0530, TL3305CF260QG and SI2333DS-T1-E3. 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 Exa tim KiCad files?
From the hasenbanck/exa_tim repository on GitHub, at the commit this page was made from: the board is pcb/exa_tim.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Exa tim design in my own project?
Its repository states no licence, so its author keeps all rights: ask hasenbanck before reusing the design.
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