ESPHome based MQTT gateway for nodes using non-wifi communication

[Laczen]

Describe the problem you have/What new integration you would like

At the moment ESPHome communication with HA servers is limited to wifi only systems. There are many non-wifi communication methods like espnow, lora, ble that are not or have limited support by ESPHome.

A general approach that allows for easy integration of nodes that are using a different communication method could be made by creating a ESPHome based (transparent) MQTT gateway that transfers the mqtt messages over espnow, lora, ble, ... and then at the node (that could also be ESPHome based) use the messages as a mqtt client.

The message transformation could be done as packing the mqtt message into a json package containing { n: node, t: topic, p: payload}.

The idea would translate to: HASS <--tcp/ip--> MQTT-broker <--tcp/ip--> MQTT-gateway (ESPHome) <--espnow,lora,ble--> MQTT-client (ESPHome, node)

The MQTT-gateway would be used only as a translater of packages and could do a broadcast of the packages, the client then decides if this is something it needs to react upon or to ignore.

Please describe your use case for this integration and alternatives you've tried:

use case: My use case consists of many nodes (light switches) that I do not want to connect to my wifi network (because of security, wifi load, messages are scarce, ...), I want these nodes to communicate over espnow and to report their state to HASS. HASS commanding the nodes would be a scarce thing.

alternatives: A different approach could be to use the same method for the ESPHome API, but this would have several disadvantages: a. In the API the nodes are servers, that does not work well with nodes that are sleeping most of the time, b. The API is a more or less HASS only solution, while MQTT is very well known and widely used.

Additional context

[Laczen]

@SenexCrenshaw, fyi

[749]

This seems like the same direction as #275 and #124