I'm looking to use Lorawan as a way to receive my probe measurements instead of the less energy effective wifi.
The problem is the following: on a Lorawan access, you can only send 140 messages per day.
The "RTC clock", rather the RTC cristal used to pace during deep sleep periods, is temperature sensitive and somehow inaccurate with quite some drift over a day.
If you have a 10 minutes deep sleep sessions, some seconds of activity to poll the probe and send the results, you can theoritically reach the 140 messages per day. (10 minutes and 17 seconds I guess) So if the device is inaccurately spamming at an imprecise rate, it could end up having message discarded by the network.
So question is : since it is not possible to sync directly to a NTP server over a Lorawan connexion, are there any option to keep a decent timing, let's say around +/- 1 seconds accuracy over a period of 10 min?
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Philippe.