2 layers22.5 × 14.5 mm Lora module, the printed circuit board in 3D

Lora module

This project aims to take a cheap, common smart watch and upgrade it by replacing the screen and all internal electronics with custom hardware.

Open in PCBKit

Size: 22.5 × 14.5 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 27
Nets: 76
Pads: 133
Tracks, vias: 0, 0
Routed: Not yet
KiCad: KiCad 7 (file 20221018)
Created: 11 Dec 2023
Updated: 17 Mar 2025

Overview

Lora module is an open-source printed circuit board by ben5049, from the ben5049/Smart-Watch repository on GitHub, published under the Apache-2.0 licence. It is a 2-layer board of 22.5 × 14.5 mm with 27 parts on 76 nets.

It is built around the BALFHB-WL-02D3 and PE42421SCAA-Z. Its parts include 11 capacitors, 3 resistors, 2 ICs, 2 diodes and 2 inductors. It belongs with the radio and wireless boards and the STM32 boards of this library.

Main components

README

README.md

Smart-Watch

Introduction

This project aims to take a cheap, common smart watch and upgrade it by replacing the screen and all internal electronics with custom hardware.

main_board_v3_front

Repository structure

/Documentation - all the documents to do with the project, including hardware and software design, datasheets, reference manuals, images etc.
/PCBs - KiCad projects for all the circuit boards used, libraries for all components, and old versions.
/Firmware - code for STM32 and nRF53 microcontrollers, including drivers for most chips.
/CAD - 3D models for components and assemblies, as well as 3D printing files.
/Simulations - Spice simulations of certain (mainly analogue) circuits.

Parts

Qty	Value	Footprint	References
4	100n	Capacitor_SMD:C_0402_1005Metric	C202, C203, C206, C210
4	10k	Resistor_SMD:R_0402_1005Metric	DNP202, R205, R207, R208
2	1k	Resistor_SMD:R_0402_1005Metric	R201, R202
2	1u	Capacitor_SMD:C_0402_1005Metric	C209, C211
2	4u7	Capacitor_SMD:C_0402_1005Metric	C207, C212
1	0R	Resistor_SMD:R_0402_1005Metric	R206
1	10-Pin_Pogo_Connector_Male	watch_footprints:10-Pin Pogo Connector Male	J401
1	10n	Capacitor_SMD:C_0402_1005Metric	C208
1	15u	footprints:Inductor 0806 (2016)	L202
1	470n	Capacitor_SMD:C_0402_1005Metric	C205
1	47n	Inductor_SMD:L_0402_1005Metric	L201
1	68p	Capacitor_SMD:C_0402_1005Metric	C204
1	BALFHB-WL-02D3	footprints:BALFHB-WL-02D3	Z201
1	LEDB	LED_SMD:LED_0603_1608Metric	D202
1	LEDR	LED_SMD:LED_0603_1608Metric	D201
1	PE42421SCAA-Z	footprints:SOT65P210X110-6N	S201
1	STM32WL55CCUx	Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm	U201
1	Watch_Module_Outline_V1	watch_footprints:Watch Module Outline V1	U101

Questions

How big is the Lora module PCB?

It measures 22.5 × 14.5 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Lora module use?

27 parts, built around the BALFHB-WL-02D3 and PE42421SCAA-Z. 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 Lora module KiCad files?

From the ben5049/Smart-Watch repository on GitHub, at the commit this page was made from: the board is PCBs/lora_module/lora_module.kicad_pcb and its schematic PCBs/archived/rfid_module_v1/boost_converter.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Lora module design in my own project?

Its repository publishes it under the Apache-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).

Category and platform

Radio and wireless STM32

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/ben5049-smart-watch-lora-module" title="Lora module in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/ben5049-smart-watch-lora-module.jpg" alt="Lora module" width="1200" height="900">

A picture that opens the board, for a README

[![Lora module](https://pcbkit.io/embed/boards/ben5049-smart-watch-lora-module.jpg?size=s)](https://pcbkit.io/boards/ben5049-smart-watch-lora-module)

Source

Repository: ben5049/Smart-Watch
Board file: PCBs/lora_module/lora_module.kicad_pcb
Commit: e2b572e
Licence: Apache-2.0

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