ESP32 Forum

I have a remote sensor and a station that have to get some data form the sensor.
Both based on ESP32. The station connected to a power supply so no problem. But the sensor is powered from a battery and it has to be as low power consumption as possible. So I think what BLE topology should I choose. If the sensor is a server it should advertise constantly and if it's a client it should scan constantly. What is more power friendly - a client or a server ?

May I use a ble_ibeacon example ? Sensor - iBeacon Sender, station - iBeacon Receiver ?

To form a connection, your client must be scanning while your server is advertising. Advertisements are sent at intervals, so you could have for example:
A client scanning constantly, with constant radio activity, meaning constant power use.
A server advertising at set intervals, with radio active only while adverts are transmitted, and therefore periodic power use.

Which is why it makes sense to have your low-power sensor device as the server.

Whether or not you use:
A periodic connection (wake up, connect, make a data transfer, disconnect, go to sleep, repeat)
A persistent connection (connect, periodically transfer, stay connected)
or
A Connectionless transfer like beacons, where data is embedded in advertisement packets and received by a scanning device without forming a connection

Depends on how much data you need to transfer and how often (as well as other a load of other considerations)

Thank you.

Is there anyway to have the battery operated server (with the sensor data) to be in some LP mode and have the Client poll it ( or something) to wake it up, connect, make a data transfer, disconnect, go to sleep, repeat?

Thanks!