2 layers40 × 78 mm
Hardware v2
rmingon/Falcon-Edge
A 3D-printable flying-wing airframe with a custom ESP32 flight computer—open hardware you can solder, screw together, and fly.
56 parts11
2 layers64 × 24 mm
Open lora com
rmingon/open-lora-comThis project is a compact, embedded hardware system designed to securely transmit data over LoRa. Built around the STM32F103 microcontroller, this system supports real-time SHA encryption, flexible protocol configuration, and communication via a CH340 USB-to-UART interface.
- Size
- 64 × 24 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 36
- Nets
- 64
- Pads
- 170
- Tracks, vias
- 397, 71
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 15 May 2025
- Updated
- 12 Jun 2025
Overview
Open lora com is an open-source printed circuit board by rmingon, from the rmingon/open-lora-com repository on GitHub. It is a 2-layer board of 64 × 24 mm with 36 parts on 64 nets, routed with 397 tracks and 71 vias.
It is built around the CH340C and RFM95W-868S2. Its parts include 13 capacitors, 9 resistors, 4 ICs, 4 connectors and 2 diodes. It belongs with the radio and wireless and interfaces and adapters boards and the STM32 boards of this library.
Main components
2README
README.mdSTM32F103 LoRa Secure Transmitter
This project is a compact, embedded hardware system designed to securely transmit data over LoRa. Built around the STM32F103 microcontroller, this system supports real-time SHA encryption, flexible protocol configuration, and communication via a CH340 USB-to-UART interface.
Features
- MCU: STM32F103C8T6
- LoRa Module: RFM95W-868S2
- USB Communication: CH340C USB-to-UART bridge
- Encryption: Real-time SHA key-based encryption
- LoRa Configurable: Change frequency, bandwidth, spreading factor, and power
- User Input: Push buttons for RESET and BOOT
- UART Configuration: Baud rate, data bits, and parity selectable
- Power Supply:
- USB input: 5V
- Onboard LDO regulator: 3.3V for logic and LoRa
- External Interfaces:
- JTAG/SWD for programming/debugging
- UART via USB
- Antenna SMA connector
Hardware Overview
Main Components
| Component | Description |
|---|---|
| U5 | STM32F103C8T6 - 32-bit ARM Cortex-M3 MCU |
| U1 | RFM95W LoRa module (868 MHz) |
| U4 | CH340C USB-UART bridge |
| U2 | LM317 3.3V voltage regulator |
| Y1 | 8 MHz crystal for MCU clock |
| J2 | USB Type-A input |
| J4 | SMA antenna connector |
Circuit Blocks
- LoRa Communication: SPI interface between STM32 and RFM95
- Encryption: SHA operations handled on-chip with optimized library routines
- Programming/Debugging: SWD header and serial boot configuration
- Indicators: Two user-controllable LEDs
- User Controls: BOOT and RESET tactile switches
Firmware & Software
The firmware handles:
- Initialization of the LoRa module (SX1276/SX1278 compatible)
- Serial communication over CH340
- SHA-256 encryption of user data before transmission
- Real-time user configuration parsing from USB input
A PC-side software GUI (in development) will provide:
- Serial interface via CH340
- Baud rate and LoRa parameter configuration
- SHA key input
- File/data input for transmission
Configuration Parameters
LoRa Settings
- Frequency: 868 MHz (default)
- Spreading Factor: SF7–SF12
- Bandwidth: 125 kHz, 250 kHz, 500 kHz
- Coding Rate: 4/5, 4/6, 4/7, 4/8
- Preamble Length: User-defined
UART Settings
- Baud Rate: 9600 / 19200 / 38400 / 57600 / 115200
- Stop Bits: 1 / 2
- Parity: None / Even / Odd
Security
- SHA Key: 128–256 bit user-defined key via software
- Mode: One-way hashing of data payloads before LoRa TX
Getting Started
- Connect via USB to your PC.
- Flash firmware via SWD or UART bootloader.
- Launch software and connect to the detected COM port.
- Configure LoRa & UART settings and set your SHA key.
- Transmit securely over LoRa.
Gallery
PCB Layout
Schematic
3D Model
Dependencies
- STM32 HAL or LL library
- SHA256 library (mbedTLS or custom-optimized)
- LoRa library (Semtech-compatible)
- CH340 driver (auto-install on most systems)
License
This project is licensed under the MIT License — use it, modify it, and share it freely.
Parts
36| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 10k | Resistor_SMD:R_0603_1608Metric | R1, R2, R3, R4, R6, R10 |
| 4 | 100n | Capacitor_SMD:C_0603_1608Metric | C6, C7, C8, C10 |
| 3 | C_Small | Capacitor_SMD:C_0603_1608Metric | C1, C2, C3 |
| 2 | 100k | Resistor_SMD:R_0603_1608Metric | R8, R9 |
| 2 | 1u | Capacitor_SMD:C_0603_1608Metric | C9, C13 |
| 2 | 20p | Capacitor_SMD:C_0603_1608Metric | C4, C5 |
| 2 | C | Capacitor_SMD:C_0603_1608Metric | C11, C12 |
| 2 | LED | Diode_SMD:D_0603_1608Metric | D1, D2 |
| 2 | SW_Push | Button_Switch_SMD:SW_SPST_CK_RS282G05A3 | SW1, SW2 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric | R7 |
| 1 | BOOT | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J3 |
| 1 | CH340C | Package_SO:SOIC-16_3.9x9.9mm_P1.27mm | U4 |
| 1 | Conn_Coaxial | Connector_Coaxial:SMA_Samtec_SMA-J-P-H-ST-EM1_EdgeMount | J4 |
| 1 | Crystal | Crystal:Crystal_SMD_HC49-SD | Y1 |
| 1 | LM317_SOT-223-3.3V | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U2 |
| 1 | RFM95W-868S2 | RF_Module:HOPERF_RFM9XW_SMD | U1 |
| 1 | STM32F103C6Tx | Package_QFP:LQFP-48_7x7mm_P0.5mm | U5 |
| 1 | SWD | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J1 |
| 1 | SolderJumper_3_Bridged12 | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm | JP1 |
| 1 | USB_A | Connector_USB:USB_Micro-B_Molex-105017-0001 | J2 |
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Questions
How big is the Open lora com PCB?
It measures 64 × 24 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Open lora com use?
36 parts, built around the CH340C and RFM95W-868S2. 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 Open lora com KiCad files?
From the rmingon/open-lora-com repository on GitHub, at the commit this page was made from: the board is hardware/hardware.kicad_pcb and its schematic hardware/hardware.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Open lora com design in my own project?
Its repository states no licence, so its author keeps all rights: ask rmingon before reusing the design.