I have an app that connects nearby phones via Bluetooth (using GameKit). I would like to fire a simple hardware event to happen at the exact same time across all peers. Is there a way to coordinate the event across all devices without having to use a server?
I thought maybe I could just use the device's internal clocks, but the trouble is, there is potential for one or more to be off. The only way I could think of is to all query the same NTP server and compare the time offsets. Trouble with this is it is: a) kind of slow in triggering the event, as I need to insert an artificial delay and b) requires a valid internet connection.
Any bright ideas for how to synchronize an event over bluetooth with precise accuracy?