2 layers
Ferris
rappet/ferris-badge
Small badge running on a coin cell using a STM32L031G6U with embassy.
23 parts1
4 layers
Eigentime32
captainchapster/Eigentime321A self-contained pocket watch that keeps its own time for a decade. No GPS, one coin cell, one PCB.
- Copper layers
- 4
- Thickness
- 0.8 mm
- Parts
- 53
- Nets
- 45
- Pads
- 211
- Tracks, vias
- 616, 75
- Pours
- 38
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 10 Oct 2026
- Updated
- 10 Oct 2026
Overview
Eigentime32 is an open-source printed circuit board by captainchapster, from the captainchapster/Eigentime32 repository on GitHub. It is a 4-layer board with 53 parts on 45 nets, routed with 616 tracks and 75 vias.
It is built around the STM32L031G6U6, SN74LV1T34DBV and SN74LV4T125PW, with the TPS61099DRV, CT8132SK-IS3 and ST25DV04KC-IE6C3 among its other parts. Its parts include 22 capacitors, 14 resistors, 8 ICs, 2 connectors and 2 switches. It belongs with the radio and wireless boards and the STM32 boards of this library.
Main components
9
STM32L031G6U6
UFQFPN-28(4x4)-40℃~+85℃ 1.8V~3.6V 12bit 1KB 21 32 Bit 32KB 32MHz 8KB ARM Cortex-M0+ Built-in FLASH UFQFPN-28(4x4) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
SN74LV1T34DBV
SOT-23-5-40℃~+125℃ 1 1 1.6V~5.5V 10uA 5.5ns@5V,15pF 74LV 8mA 8mA Level shifting Push-pull Unidirectional SOT-23-5 Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
SN74LV4T125PW
TSSOP-14-40℃~+125℃ 1 1.6V~5.5V 16mA 16mA 20uA 3.2ns@5V,15pF 4 74LV Tri-State Unidirectional TSSOP-14 Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
TPS61099DRV
WSON-6-EP(2x2)-40℃~+150℃@(TJ) 1 1.8V~5.5V 700mV~5.5V Adjustable Boost Boost Built-in Yes WSON-6-EP(2x2) DC-DC Converters ROHSTexas InstrumentsDC-DC Converters
CT8132SK-IS3
SOT-23-3-40℃~+85℃ 1.7V~5.5V 10Hz 190nA 3mA 5Gs 9Gs Omnipolar Push-pull SOT-23-3 Hall Switches ROHSAllegro MicroSystems, LLCHall SwitchesST25DV04KC-IE6C3
UFDFPN-8(2x3)UFDFPN-8(2x3) RFID ICs ROHSSTMicroelectronicsRFID ICs
AYF531035
SMD,P=0.5mm,卧贴-55℃~+85℃ 0.3mm 0.5mm 10P 1mm Bottom Contact Copper alloy Gold Hinged Lid Surface Mount, Right Angle SMD,P=0.5mm,卧贴 FFC, FPC (Flat Flexible) Connector Assemblies ROHSPanasonicFFC, FPC (Flat Flexible) Connector Assemblies
CR2032
-- Unclassified goods ROHSMaxellUncategorised
DMG2305UX
SOT-23-55℃~+150℃ 1 P-Channel 1.7W 190pF 1V 20V 4.1A 52mΩ@4.5V 7.8nC 740pF P-Channel SOT-23 MOSFETs ROHSTECH PUBLICMOSFETs
README
hardware/README.mdHardware
KiCad project goes here (Eigentime32.kicad_pro). Schematic order: power → RTC → MCU → LCD → lid/buttons → NFC.
Board: ~40 mm round, 0.8 mm, 2 layers. Front side bare under the LCD; all parts on the back around the CR2032 holder.
Parts
53| Qty | Value | Footprint | References |
|---|---|---|---|
| 10 | 100n | Capacitor_SMD:C_0402_1005Metric | C3, C9, C10, C11, C12, C15, C16, C17, C20, C21 |
| 5 | 1M | Resistor_SMD:R_0402_1005Metric | R3, R5, R12, R13, R14 |
| 5 | 1u | Capacitor_SMD:C_0402_1005Metric | C7, C13, C18, C19, C23 |
| 4 | 10k | Resistor_SMD:R_0402_1005Metric | R6, R7, R9, R10 |
| 4 | 10u | Capacitor_SMD:C_0603_1608Metric | C4, C5, C6, C14 |
| 1 | 100k | Resistor_SMD:R_0402_1005Metric | R15 |
| 1 | 100u | Capacitor_SMD:C_1206_3216Metric | C2 |
| 1 | 1u | Inductor_SMD:L_Wuerth_MAPI-2512 | L1 |
| 1 | 200k | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 402k | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 470 | Resistor_SMD:R_0402_1005Metric | R4 |
| 1 | 470k | Resistor_SMD:R_0402_1005Metric | R8 |
| 1 | 470n | Capacitor_SMD:C_0402_1005Metric | C8 |
| 1 | AYF531035 | Eigentime32:Panasonic_AYF531035_1x10-1MP_P0.5mm_Horizontal | J2 |
| 1 | BTN1 | Button_Switch_SMD:SW_SPST_EVQP7A | SW2 |
| 1 | BTN2 | Button_Switch_SMD:SW_SPST_EVQP7A | SW3 |
| 1 | CLKOUT | TestPoint:TestPoint_Pad_D1.0mm | TP1 |
| 1 | CR2032 | Eigentime32:BatteryHolder_Keystone_3034_1x20mm_SmallNegPad | BT1 |
| 1 | CT8132SK-IS3 | Package_TO_SOT_SMD:SOT-23 | U9 |
| 1 | DMG2305UX | Package_TO_SOT_SMD:SOT-23 | Q1 |
| 1 | DNP | Capacitor_SMD:C_0402_1005Metric | C22 |
| 1 | NFC coil | Eigentime32:NFC_PCB_Coil_D38.1mm_8T | AE1 |
| 1 | RV-3032-C7 | Package_SON:MicroCrystal_C7_SON-8_1.5x3.2mm_P0.9mm | U1 |
| 1 | SN74LV1T34 | Package_TO_SOT_SMD:SOT-353_SC-70-5 | U7 |
| 1 | SN74LV4T125 | Eigentime32:Texas_RGY0014A_VQFN-14-1EP_3.5x3.5mm_P0.5mm_EP2.05x2.05mm | U6 |
| 1 | ST25DV04KC-IE6C3 | Package_DFN_QFN:DFN-8-1EP_3x2mm_P0.5mm_EP1.36x1.46mm | U8 |
| 1 | STM32L031G6U6 | Package_DFN_QFN:QFN-28_4x4mm_P0.5mm | U2 |
| 1 | TC2030-NL | Eigentime32:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical_FootprintsAllowed | J1 |
| 1 | TPS22916C | Package_BGA:Texas_PicoStar_BGA-4_0.758x0.758mm_Layout2x2_P0.4mm | U5 |
| 1 | TPS61099DRV | Package_SON:WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm | U3 |
Questions
What parts does the Eigentime32 use?
53 parts, built around the STM32L031G6U6, SN74LV1T34DBV, SN74LV4T125PW and TPS61099DRV. 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 Eigentime32 KiCad files?
From the captainchapster/Eigentime32 repository on GitHub, at the commit this page was made from: the board is hardware/Eigentime32.kicad_pcb and its schematic hardware/Eigentime32.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Eigentime32 design in my own project?
Its repository states no licence, so its author keeps all rights: ask captainchapster before reusing the design.
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