This guide describes how to build a MeshCore repeater using the compact ESP32-C3 Super Mini board, an SX1262 (RA62) LoRa module, and an optional DS3231 RTC for precise timekeeping.
- ESP32-C3 Super Mini
- SX1262 LoRa Module (e.g., Ebyte E22 or RA62)
- DS3231 RTC Module (optional, for offline timekeeping)
- TP4056 Charging Module
- 3.7V Li-Po or Li-ion Battery
- LoRa Antenna (appropriate for your frequency, e.g., 868MHz)
| SX1262 Pin | ESP32-C3 Pin | Description |
|---|---|---|
| VCC | 3.3V | Power (3.3V) |
| GND | GND | Ground |
| NSS | GPIO 8 | SPI Chip Select |
| SCK | GPIO 10 | SPI Clock |
| MOSI | GPIO 7 | SPI MOSI |
| MISO | GPIO 6 | SPI MISO |
| DIO1 | GPIO 3 | Interrupt |
| BUSY | GPIO 4 | Busy Signal |
| RESET | GPIO 5 | Reset |
Note: Make sure to use the I2C pins defined in the configuration (GPIO 1 & 2).
| DS3231 Pin | ESP32-C3 Pin | Description |
|---|---|---|
| VCC | 3.3V | Power (3.3V) |
| GND | GND | Ground |
| SDA | GPIO 1 | I2C Data |
| SCL | GPIO 2 | I2C Clock |
- TP4056 B+ / B-: Connect to the Battery terminals.
- TP4056 OUT+: Connect to ESP32-C3 5V (VBUS) pin.
- TP4056 OUT-: Connect to ESP32-C3 GND.
- Antenna: NEVER power on the LoRa module without an antenna connected. It can damage the chip.
- I2C Pull-ups: The DS3231 module usually has built-in pull-up resistors. If you are using raw chips, add 4.7kΞ© resistors between SDA/SCL and 3.3V.
- Battery: A 18650 cell or a flat Li-Po battery works great for long-term repeater use.
- Power Saving: You can remove or cut the PowerLED on the ESP32-C3 and the LED on the RTC module to save approximately 2mA of current. An idle current of ~7.5mA can be achieved with
powersaving onenabled in the CLI.
The simple_repeater example supports periodic text messages that can be sent to a specific channel. These settings are persisted to the device's filesystem.
CLI Commands:
periodic <interval_seconds>: Set the interval in seconds between messages.periodic interval <seconds>: Same as above.periodic hour <0-23>: Set a specific hour (UTC) to send a daily message.periodic text <message>: Set the text content of the message.periodic chan <name>: Set the channel name (e.g.,Public).periodic key <hex_key>: Set the 32-character hex secret key for the channel.
MeshCore is a lightweight, portable C++ library that enables multi-hop packet routing for embedded projects using LoRa and other packet radios. It is designed for developers who want to create resilient, decentralized communication networks that work without the internet.
MeshCore now supports a range of LoRa devices, allowing for easy flashing without the need to compile firmware manually. Users can flash a pre-built binary using tools like Adafruit ESPTool and interact with the network through a serial console. MeshCore provides the ability to create wireless mesh networks, similar to Meshtastic and Reticulum but with a focus on lightweight multi-hop packet routing for embedded projects. Unlike Meshtastic, which is tailored for casual LoRa communication, or Reticulum, which offers advanced networking, MeshCore balances simplicity with scalability, making it ideal for custom embedded solutions, where devices (nodes) can communicate over long distances by relaying messages through intermediate nodes. This is especially useful in off-grid, emergency, or tactical situations where traditional communication infrastructure is unavailable.
- Multi-Hop Packet Routing
- Devices can forward messages across multiple nodes, extending range beyond a single radio's reach.
- Supports up to a configurable number of hops to balance network efficiency and prevent excessive traffic.
- Nodes use fixed roles where "Companion" nodes are not repeating messages at all to prevent adverse routing paths from being used.
- Supports LoRa Radios β Works with Heltec, RAK Wireless, and other LoRa-based hardware.
- Decentralized & Resilient β No central server or internet required; the network is self-healing.
- Low Power Consumption β Ideal for battery-powered or solar-powered devices.
- Simple to Deploy β Pre-built example applications make it easy to get started.
- Off-Grid Communication: Stay connected even in remote areas.
- Emergency Response & Disaster Recovery: Set up instant networks where infrastructure is down.
- Outdoor Activities: Hiking, camping, and adventure racing communication.
- Tactical & Security Applications: Military, law enforcement, and private security use cases.
- IoT & Sensor Networks: Collect data from remote sensors and relay it back to a central location.
- Watch the MeshCore QuickStart Playlist by The Comms Channel
- Watch the MeshCore Technical Presentation by Liam Cottle.
- Read through our Frequently Asked Questions and Documentation.
- Flash the MeshCore firmware on a supported device.
- Connect with a supported client.
For developers:
- Install PlatformIO in Visual Studio Code.
- Clone and open the MeshCore repository in Visual Studio Code.
- See the example applications you can modify and run:
- Companion Radio - For use with an external chat app, over BLE, USB or Wi-Fi.
- KISS Modem - Serial KISS protocol bridge for host applications. (protocol docs)
- Simple Repeater - Extends network coverage by relaying messages.
- Simple Room Server - A simple BBS server for shared Posts.
- Simple Secure Chat - Secure terminal based text communication between devices.
- Simple Sensor - Remote sensor node with telemetry and alerting.
The Simple Secure Chat example can be interacted with through the Serial Monitor in Visual Studio Code, or with a Serial USB Terminal on Android.
We have prebuilt firmware ready to flash on supported devices.
- Launch https://meshcore.io/flasher
- Select a supported device
- Flash one of the firmware types:
- Companion, Repeater or Room Server
- Once flashing is complete, you can connect with one of the MeshCore clients below.
Companion Firmware
The companion firmware can be connected to via BLE, USB or Wi-Fi depending on the firmware type you flashed.
- Web: https://app.meshcore.nz
- Android: https://play.google.com/store/apps/details?id=com.liamcottle.meshcore.android
- iOS: https://apps.apple.com/us/app/meshcore/id6742354151?platform=iphone
- NodeJS: https://github.com/liamcottle/meshcore.js
- Python: https://github.com/fdlamotte/meshcore-cli
Repeater and Room Server Firmware
The repeater and room server firmware can be set up via USB in the web config tool.
They can also be managed via LoRa in the mobile app by using the Remote Management feature.
MeshCore is designed for devices listed in the MeshCore Flasher
MeshCore is open-source software released under the MIT License. You are free to use, modify, and distribute it for personal and commercial projects.
Please submit PR's using 'dev' as the base branch! For minor changes just submit your PR and we'll try to review it, but for anything more 'impactful' please open an Issue first and start a discussion. It is better to sound out what it is you want to achieve first, and try to come to a consensus on what the best approach is, especially when it impacts the structure or architecture of this codebase.
Here are some general principles you should try to adhere to:
- Keep it simple. Please, don't think like a high-level lang programmer. Think embedded, and keep code concise, without any unnecessary layers.
- No dynamic memory allocation, except during setup/begin functions.
- Use the same brace and indenting style that's in the core source modules. (A .clang-format is probably going to be added soon, but please do NOT retroactively re-format existing code. This just creates unnecessary diffs that make finding problems harder)
Help us prioritize! Please react with thumbs-up to issues/PRs you care about most. We look at reaction counts when planning work.
To run unit tests, run the following command:
pio test --environment native --verboseThere are a number of fairly major features in the pipeline, with no particular time-frames attached yet. In very rough chronological order:
- Companion radio: UI redesign
- Repeater + Room Server: add ACL's (like Sensor Node has)
- Standardise Bridge mode for repeaters
- Repeater/Bridge: Standardise the Transport Codes for zoning/filtering
- Core + Repeater: enhanced zero-hop neighbour discovery
- Core: round-trip manual path support
- Companion + Apps: support for multiple sub-meshes (and 'off-grid' client repeat mode)
- Core + Apps: support for LZW message compression
- Core: dynamic CR (Coding Rate) for weak vs strong hops
- Core: new framework for hosting multiple virtual nodes on one physical device
- V2 protocol spec: discussion and consensus around V2 packet protocol, including path hashes, new encryption specs, etc
- Report bugs and request features on the GitHub Issues page.
- Find additional guides and components on my site.
- Join MeshCore Discord to chat with the developers and get help from the community.