Send ble advertising and transmit the message on BLE at certain interval and then sleep and wake at regular interval

[sara]

I have an application that works on nrf52832 that when it is powered on is expected to read a sensor data for initial 10 seconds if any, and then start BLE advertising for 5 sec and then after 2 sec it goes to sleep and wakes up every 5 minutes. And for the application power consumption should be minimal. Kindly help me with what example should I start with so that all my criteria gets fulfilled.

[Hung Bui]

Hi, 

There wouldn't be an example does exactly the same as you described. But I don't see any problem making such an application. I would suggest to get started with an BLE example in our SDK. You can start with ble_app_pwr_profiling or ble_app_hrs.

If you find the advertising module is too complex to use, you can think of using the Softdevice APIs directly to do advertising. 

You can have a look at this tutorial: https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-advertising-a-beginners-tutorial

[sara]

Ok, thank you. And if I want to use freertos so how should I port it with ble example? I have referred the following link: https://devzone.nordicsemi.com/f/nordic-q-a/35386/application-with-freertos---lowest-possible-current-in-idle so I am a bit worried because I too need a power-optimized freertos working example with BLE, where a system on current should be around 2 uA and not more than that.

[sara]

I tried with disabling NRF_LOG_ENABLED  but I am getting some other peaks which I have encircled yellow in the image attached. so why is this ? rest currrent measuremnts are ok but getting these peaks. system on  current is 1.733 uA and system off current is 0.412 uA.

[Hung Bui]

Please state which firmware you are using ?  Looks like the CPU woken up to do something. 

[sara]

I had used ble_app_hrs_freertos example from SDK 15.3.0. 

[Hung Bui]

Do you have a particular reason why you need to use FreeRTOS for such application ? For power optimization it's not suggested to use FreeRTOS if not needed. 

[sara]

I need freertos to prioritize the different tasks