Which role provides lowest power consumption while conneced to other BLE device?

[M_VLV]

Hi,

I will connect nRF52840 with other BLE module (ESP32) and they must exchange data (at first aproximation 20-50 bytes each 1-5 seconds).

I need to acheive lowest power consumption on nRF52 side as possible.

Please advice which of modules should intend as central/peripheral. I suppose, nRF52 should be peripheral, am I correct?

And one more thing, should both devices always keep ble connection open or I need to pair/connect only when I need to exchange data?

Regards

[Einar Thorsrud]

Hi,

The BLE protocol is designed to be more power efficient for the peripheral, on the expense of the central. So typically, the device with the tightest power budget should be the peripheral.

Scanning and advertising is typically energy demanding (using the radio extensively), so keeping the connection active is usually the most power efficient. In the case you describe, where the devices should communicate every few seconds, maintaining the connection is definitively preferable.