2 layers68 × 40 mm
Stm32-io extend
hardenedlinux/cheap-pcb
Cheap PCB: Better understanding the current status of hardware supply chain
44 parts170CC0-1.0
4 layers61 × 36 mm
Linklet
FerretCode/linkletA LoRa enabled modular sensor bus
- Size
- 61 × 36 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 46
- Nets
- 61
- Pads
- 184
- Tracks, vias
- 376, 84
- Pours
- 7
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 22 Sep 2025
- Updated
- 24 Dec 2025
Overview
Linklet is an open-source printed circuit board by FerretCode, from the FerretCode/linklet repository on GitHub. It is a 4-layer board of 61 × 36 mm with 46 parts on 61 nets, routed with 376 tracks and 84 vias.
It is built around the STM32F103C8T6 and AMS1117-3.3. Its parts include 13 capacitors, 9 resistors, 6 connectors, 3 ICs and 3 diodes. It belongs with the STM32 boards of this library.
Main components
2
STM32F103C8T6
LQFP-48(7x7)-40℃~+85℃ 12bit 20KB 2V~3.6V 32 Bit 37 64KB 72MHz ARM Cortex-M3 Built-in FLASH LQFP-48(7x7) 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
README
README.mdlinklet
A modular, LoRa enabled sensor bus
Overview
- Linklet is an custom PCB design with an STM32 and RFM69HCW LoRa modules for sensing and IoT operations
- The base board exposes 1x UART and 1x I2C interface for basic sensors
- The board is powered over micro-USB
- Linklet also exposes a 1x8 pin socket connector for carrying daughter boards
- The connector has 1x UART and 1x I2C interface for daughter boards
- It makes it easy for swapping out different sensor arrays on the fly
Parts
46| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 1k5 | Resistor_SMD:R_0402_1005Metric | R2, R3, R4, R5, R8, R9 |
| 5 | 100n | Capacitor_SMD:C_0402_1005Metric | C1, C2, C3, C4, C9 |
| 4 | MountingHole | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4 |
| 3 | Conn_01x04_Pin | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J2, J3, J4 |
| 3 | Fiducial | Fiducial:Fiducial_1mm_Mask2mm | FID1, FID2, FID3 |
| 3 | RED | LED_SMD:LED_0603_1608Metric | D1, D2, D3 |
| 2 | 10p | Capacitor_SMD:C_0402_1005Metric | C10, C11 |
| 2 | 1k | Resistor_SMD:R_0402_1005Metric | R6, R7 |
| 2 | 1u | Capacitor_SMD:C_0402_1005Metric | C7, C8 |
| 2 | 22u | Capacitor_SMD:C_0805_2012Metric | C12, C13 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R1 |
| 1 | 10n | Capacitor_SMD:C_0402_1005Metric | C6 |
| 1 | 10u | Capacitor_SMD:C_0603_1608Metric | C5 |
| 1 | 16MHz | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | 220R | Inductor_SMD:L_0603_1608Metric | FB1 |
| 1 | AMS1117-3.3 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U2 |
| 1 | Conn_01x08_Socket | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J7 |
| 1 | Conn_Coaxial | Connector_Coaxial:SMA_Molex_73251-1153_EdgeMount_Horizontal | J6 |
| 1 | LOGO | LOGO | G*** |
| 1 | RFM69HCW | RF_Module:HOPERF_RFM9XW_SMD | U3 |
| 1 | STM32F103C8T6 | Package_QFP:LQFP-48_7x7mm_P0.5mm | U1 |
| 1 | SW_SPDT | Button_Switch_SMD:SW_SPDT_PCM12 | SW1 |
| 1 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_Pad1.0x1.5mm | JP1 |
| 1 | USB_B_Micro | Connector_USB:USB_Micro-B_Wuerth_629105150521 | J1 |
Questions
How big is the Linklet PCB?
It measures 61 × 36 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Linklet use?
46 parts, built around the STM32F103C8T6 and AMS1117-3.3. 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 Linklet KiCad files?
From the FerretCode/linklet repository on GitHub, at the commit this page was made from: the board is hardware/linklet.kicad_pcb and its schematic hardware/linklet.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Linklet design in my own project?
Its repository states no licence, so its author keeps all rights: ask FerretCode before reusing the design.
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