We have a peripheral device that we would like to have sleeping 99% of the time. I have a single timer waking it at 1-second intervals to look for things it might need to do. One of those things is seeing another device it will want to connect to over BLE. I can't afford the power of turning the radio on and advertising at a regular interval, so I need some way to signal the device to do that only when needed. We have one device that uses a physical button, and one that uses a reed switch, but we want to make another device embedded in an environment that makes these difficult.
So my question is, is there any way for the unit to either wake up from sleep on some wireless signal, or in the few milliseconds per second it is already awake to passively receive a radio signal telling it to start advertising? Perhaps I need to switch to central device mode and let the phone be peripheral (This is possible on a Nexus 6 and a few other phones)?
