Mesh networking board by Daniel on Hackaday.io:

Low-power mesh networking for small sensor grids

Tiny MQTT-interoperable broadcast mesh networking with simple radios

This project is a low-resource mesh networking stack and mote with battery-powered routers based on state synchronization. The target is for the stack to use less than 2kb SRAM. Nodes use low power listening and an adaptive gossip protocol to synchronize key/values pairs with each other without relying on explicit routing or per-node addressing.

For example, a light might transmit (/lamp, {“state”:”on”}) to the mesh. Write (/lamp, {“state”:”off”}) to the mesh, and the lamp application will notice. The powerful but simple state synchronization primitive allows you to update the state of the mesh to update the world, and update the state of the world to express the same on the mesh. Trivially bridged to a private MQTT server and managed with off-the-shelf MQTT applications.

The design files and source code are available on Bitbucket:

dholth/mesh