Optimizing Power Consumption in BLE Geofencing Project and Enabling DFU on nRF52820 SoC / nRF52833DK

[Jhakan]

Hello Team,
We are currently working on a new project that incorporates geofencing functionality using BLE.

We have checked the current consumption  in nRF52833 DK using  the Power profiler Kit II  and tested with  two different builds .I have provided the file path below for your reference
1.https://github.com/nrfconnect/sdk-zephyr/blob/1aa2f9d42791ff37061af43aa8fa97120f9fbeb7/samples/bluetooth/peripheral_gatt_write/src/peripheral_gatt_write.c
2.https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/central_and_peripheral_hr/README.html

In the Peripheral_Gatt_write build the observed current values are as below:
a.Average Current consumed when BLE advertising : 608.17 uA
b.Average Current consumed when BLE connected with mobile using nRFConnect App : 700 uA.

In the Central_and_Peripheral_hr build  the observed current values are as below:
a.Average Current consumed when BLE advertising : 2.56 mA
b.Average Current consumed when BLE connected with mobile using nRFConnect App : 2.56 mA

QUERIES:

• Using the "Central_and_Peripheral_h" build,  we observe current in mA. Can this be reduced below 100 µA? Suggest ways to operate in lower power( in uA), including low-power modes, and steps to disable GPIOs for updated power measurement.

• Can DFU be enabled on the nRF52820? If yes, please share the procedure.

• In System ON Low Power mode, can our geofencing app run while minimizing power consumption? Will the RTC remain functional in this mode? Also,when verified in the nRF52820 Datasheet we couldn't find the current consumed in the Low Power mode. Where can we find exact current consumption for Low Power or Constant Latency modes?
  1.Central_and_Peripheral_hr: 
  
  2. Peripheral_Gatt_write
  
  
  

[Simonr]

Hi

First off, what will the use case of this geofencing be on your end. Bluetooth LE doesn't have very high range and can never be 100% fault proof in terms of reliability. 

1. Yes, I think you should be lower the power consumption of the central_and_peripheral_hr. During advertising and connections lowering it below 100µA might be to expect too much, depending on the parameters you require of course. You can use the Online Power Profiler for some estimates on what to expect in various Bluetooth operations. Since you see current consumption on multiple mA's I'm guessing debugging/logging and serial is enabled, as those tend to draw a lot of power. That being said. These current consumption plots seem very strange, and it doesn't seem like an application operating as expected. Can you show me how the PPK2 is connected to the device you're measuring on exactly?

2. DFU is not really relevant to this ticket's subject, and I'd strongly recommend you create a new topic on the DFU issue, as it's much easier to have an overview if we have one ticket per topic, so please create a new one on the DFU topic and an engineer proficient in DFU will take a look.

3. In System ON low power mode (assuming you refer to the modes specified in the product specification, the radio will be turned off, so a geofencing solution (or anything using the radio) won't be able to run at single digit µA current consumption. The RTC can run in low power idle modes though, but not much else. It is normal to use this if you only need to wake up and advertise every now and then, so the device can spend most of its time in this mode and wake up every minute or so to do an advertisement/connection of some kind.

Best regards,

Simon