Recommended GAP Role for Battery Powered Device

[sireeshad]

Hi All,

We are in evaluation phase of a project where in our battery powered device would use nrF52840 MCU and communicate to the mobile phone over BLE (say about 5x times a day) and the target battery life of the device is ~1 year.

What is the recommended BLE GAP role for such battery powered device? - First impression is to the device should be a peripheral and work on advertising intervals for better discovery time while not compromising on current consumption. Any inputs on this?

Does Nordic has any data/estimates on advertising and connection times and their current consumption for nrF52840 in general sense, as we are also interested on the read-times when a Mobile device-Our product come in contact.

Appreciate any feedback or suggestions. 

Thanks

SD

[Susheel Nuguru]

It depends on how much data you want to send each time even though you send 5 times a day. If it is only few bytes everytime, then I think the GAP advertising role fits your use case well. The current consumption in terms of RADIO current is the same in any role, as the TX/RX currents are constant in a chip. What changes is the pre and post processing of the RADIO event by the softdevice and the application as this can vary per GAP role. 

The online power profiler kit is a best tool for you to experiment and get the average power consumption for different roles They give you close to accurate results as they have been tested a lot before putting the values in there. 

With few bytes transfer each time and 5 times a day, getting a battery life of 1 year is not a problem at all. There are so many mouse/keyboard applications out there that use our solutions which transfer data thousands of times a day and still cope up with 6 months to 1 year of battery life.