Best communication concept for 20 Controllers

  • Hello ... I have a conceptual question. I want to connect about 20 controllers with different tasks without internet in one vehicle.

    Logically, each controller should receive all requests and then pick out those that are relevant to it. And each controller should be able to send such a broadcast.

    What is the most efficient and robust method in terms of energy consumption? Radio must be used. Most (or all) controllers are ATOM Lite. UIflow has to be used.

    Option A: The simplest case would be to connect via WIFI, where everyone is connected and then communicates via MQTT. This requires a central router and broker. But WIFI is supposed to consume a lot of energy and all devices have to be online all the time.

    Option B: ESP NOW is great for networking two controllers in one direction, but such a bidirectional mesh is quite difficult to establish stably in the latest version.

    Option C: What would be even better?

  • @mchott Speaking personally, I would have the Master also arbitrate the Slaves by polling them one at a time. Yes, they can all talk at once but it's messy. I have a Master talking to two Slaves ESP-NOW peer to peer with small size of data and no urgency in the process. I may send a simple boolean flag to one to turn on a heater, next sending a int value to the other to set a servo position. (this one also returns a float with the Vent Temp.