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espressif / esp-now

A connectionless Wi-Fi communication protocol
Apache License 2.0
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Problem when init security key from wifi enabled node to espnow node (AEGHB-109) #62

Closed grodansparadis closed 1 year ago

grodansparadis commented 1 year ago

I still have some problems with transfer of the security key to a node that need it. My plan has been to have an init button on all nodes and espnow nodes get there security keys from wifi enabled nodes which are initiators. That way forming a cluster of nodes around a wifi enabled node.

So when I press the init button on a responder node it executes espnow_sec_responder_start(POP); and on the initiator when I press the button it executes security sample.

This works perfect if the initiator nodes wifi is not provisioned. But as soon as it is it does not work. It appears that the espnow node does not get any messages from the initiator.

I must have missed something and don't have a clue right now what to add/change. Any hints are welcome.

grodansparadis commented 1 year ago

To add to this. If I manually set the same channel on the responder as the initiator everything works as I expect. The question is still how to let it know the channel without wifi credentials.

lhespress commented 1 year ago

@grodansparadis The root reason is that the responder node doesn't know the initiator's channel when it connected with wifi if the channel changed. So you need add a method to sync the channel:

  1. Responder announce a SYNC message on all channels periodicity which only initiator response the ACK, and then set the channel after receive the ACK from the initiator.
  2. Store the channel firstly when initiator connect with the wifi, then wait for disconnected and announce a SYNC message on all channels which only responder response the ACK. connect the wifi again after receive the ACK from the responder. Responder set the SYNC channel after response the 'ACK'.
grodansparadis commented 1 year ago

@lhespress Hi thanks for your always kind and prompt response. To move along with my project I added some probe code yesterday that probe all channels for a counterpart and find the channel and that solve the problem. I just thought this was in the espnow code somewhere and that I misses something. Thanks for clarifying!