I've looked at various tutorials for Arduinos / Bluetooth (HC05) / MIT App Inventor (or similar) and none of the seem to discuss timings.
(I don't have specific code to share - this is just trying to understand principals at the moment.)
In each tutorial, the Arduino performs a Serial.print() at some point in the sketch, and the Android app checks for data periodically. The timings do not seem to need explicit synchronisation.
Presumably there's some sort of sync-ing going on, either when the server and client are paired, or periodically, or both. But other than that, I can't see how you know the "send" and "receive" will coincide. Maybe, once the HC05 receives data from.the Arduino, it transmits that data until it's told not to ... bit that seems unlikely. Or maybe the data is transmitted until it is received ... more likely.
I've done some searching on this, but have not found a simple answer. Help?!
(Be gentle with me, oh wise and patient uber_geeks. I am, like Pooh, a bear of very little brain.)