dave-in-nj:
I was thinking that the mini on the remote sends our a pulse every couple seconds, then the uno in the house receives that and they both go merrily on their way.if the pulse does not come, then the uno would send out a request and the mini would respond. and then they would go back to the mini sending out pulses at intervals.
I don't understand the purpose of the UNO's request. The Mini will be sending out regular messages anyway - it doesn't need a request from the UNO to tell it to do that, and I don't see what effect the UNO's message is intended to have on it. The only situation I can think of where this sort of thing might be called for is where the Mini doesn't know which device(s) it needs to send the messages to, so one (or more?) UNOs would register with it to request that it send them the messages. In that case it might make sense for the UNO to re-register after a timeout, in case the Mini has restarted and lost its registration state.