agessaman
e242cc6fd3
[P1] A failed setup no longer strands the slot. setupSlot() returns bool and the startup loops count only successful activations, so a slot that fails on a client allocation neither consumes an active-slot position (starving a later healthy broker on capped hardware) nor sits dead forever: maintainSlotConnections() previously skipped clientless slots and the reconnect ladder is gated on initial_connect_done, so nothing retried it. It now retries an enabled but unactivated slot on a 60 s timer, one per cycle, gated on the same _slots_setup_done ordering so the NTP-deferred setup sequence is preserved. [P2] JWT setup no longer proceeds without a usable token. Both the preset and custom-audience paths returned after ignoring createSlotAuthToken()'s result, then called connect() and latched initial_connect_done -- so the token-allocation failure introduced by the previous commit produced an unauthenticated attempt exactly when memory was exhausted. They now return false and let the retry path handle it. [P2] ensureSlotAuthToken() no longer clears an existing token. It cleared unconditionally, so every renewal wiped the current token before JWTHelper ran; a renewal that then failed left an empty password where the inline buffer used to preserve working credentials (JWTHelper writes only on success). Only freshly allocated buffers are initialised now. [P2] Raw publications reuse the shared document. buildRawJSON() reached MQTTPayloadBuilder::buildRawMessage(), which constructed its own default JsonDocument and therefore malloc'd and freed an internal-heap variant pool per message -- on the highest-rate topic. The document is threaded through both builders and the bridge passes _json_scratch_doc. [P3] The writeTo() guard validates the source fields, not just the destination. A corrupt payload_len of MAX_PACKET_PAYLOAD + 1 still leaves getRawLength() inside MAX_TRANS_UNIT, so writeTo() read past packet->payload. Sizing and validation moved to a pure MQTTWireScratch header with host tests covering the accept/reject edges, matching the MQTTPacketFilter/MQTTConnectionPolicy pattern. Two findings fell out: MAX_PATH_SIZE one-byte hops is not encodable (the hop count is 6 bits, so 64 & 63 == 0; 32 two-byte hops is the widest real path), and a zero-payload packet serializes but does not survive readFrom() -- pinned as a test because it constrains any future wire-only queue. [P3] Corrected the pool-size comment: these targets are 32-bit, so ARDUINOJSON_SLOT_ID_SIZE is 2 and a pool block is 128 slots / 1024 bytes, not 4096. The 4096 figure came from a pre-existing comment near NEIGHBORS_DOC_POOL_BUDGET, which is left alone -- its byte measurements are empirical and still stand, only the block-size attribution is wrong. Activation is now centralized in activatedSlotCount()/canActivateSlot(), used by both startup loops, the retry path, and applySlotPreset(). That closes the pre-existing divergence where a live preset change called setupSlot() without consulting _max_active_slots, letting a non-PSRAM board reach three concurrent TLS sessions against a cap of two. BEHAVIOUR CHANGE: a reconfigure that would exceed the cap now logs and leaves the slot inactive instead of connecting. Reconfiguring an already-active slot still works, because teardownSlot() releases its position first. 272/272 native tests pass (5 new); both observer envs and an nRF52 repeater build clean. Flash 1593249 B non-PSRAM, 1555625 B PSRAM.
About MeshCore
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.
🔍 What is MeshCore?
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.
MQTT Observer Setup — Prebuilt observer firmware, docs, and a changelog are at observer.gessaman.com. See the MQTT Implementation Guide for configuration, CLI commands, and troubleshooting.
⚡ Key Features
- 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 – Works with Heltec, RAK Wireless, and other LoRa-based hardware.
- Decentralized & Resilient – No central server or internet required; the network is self-healing.
- Low Power Consumption – Ideal for battery-powered or solar-powered devices.
- Simple to Deploy – Pre-built example applications make it easy to get started.
🎯 What Can You Use MeshCore For?
- 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.
🚀 How to Get Started
- 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.
⚡️ MeshCore Flasher
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.
📱 MeshCore Clients
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.
🛠 Hardware Compatibility
MeshCore is designed for devices listed in the MeshCore Flasher
📜 License
MeshCore is open-source software released under the MIT License. You are free to use, modify, and distribute it for personal and commercial projects.
Contributing
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.
Running unit tests
To run unit tests, run the following command:
pio test --environment native --verbose
Road-Map / To-Do
There 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
📞 Get Support
- 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.