Can the MetaWear initiate BLE data transmission unprompted?
I'm trying to minimize power usage on the MetaWear device for an application that requires short bursts of sensor data triggered by a changing input on a gpio pin. I'd like to understand a little bit more about the MetaWear BLE protocol to make sure I'm not accidentally creating a ton of unnecessary traffic (and therefore power draw) with my setup.
My fundamental question is whether the MetaWear can initiate a BLE transaction or whether the phone has to prompt it every time. The reason I'm asking is because, in the ideal scenario, the device will locally monitor the pin and initiate sending of accel and gyro data on a transition - looking through the SDK I can see the tools to do this, or at least something close to it. However, if the underlying mechanism is the phone constantly polling the device to ask if it has any data or if the pin has changed, then it seems that all I'm really doing is creating a lot of BLE traffic and adding to the power drain. In that case I'd rather handle all of the state changes explicitly on the phone so that I can at least control the polling parameters myself.
If anyone can give me some insight into this, suggest a different approach, or just offer general tips on minimizing power usage, I'd really appreciate it. Thanks in advance for any help!