Power Usage when connected to nRF Connect Android App

RE: Power Usage when connected to nRF Connect Android App

Kazi Afroza Sultana — Mon, 22 Aug 2022 12:00:57 GMT

Hello Gary,

This is the file : zephyr\subsys\bluetooth\host\gatt.c

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: Power Usage when connected to nRF Connect Android App

Gary T — Fri, 19 Aug 2022 14:34:35 GMT

Hi Kazi

That's perfect. I hadn't set the timeout value.

I have set it now and it works correctly.

When the max is set to 500ms the power usage is 15µA. Very nice!

When set to 4s the power usage is only 7µA but the response times when pulling data are too slow.

Please let me know which file you extracted the screenshot from.

Thanks for your help.

Regards

Gary

RE: Power Usage when connected to nRF Connect Android App

Kazi Afroza Sultana — Fri, 19 Aug 2022 13:57:24 GMT

Hello Gary,

Is the preferred time is 1/4 of the supervision timeout in your configuration?

This is another requirement for preferred connection interval.

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: Power Usage when connected to nRF Connect Android App

Gary T — Tue, 16 Aug 2022 07:37:49 GMT

Hi Kazi

Thank you for your feedback.

I was successful in changing the connection interval from the default (~45ms to around ~150ms) by adding the CONFIG's you mention below to the PRJ.conf file.

Interestingly, if I set the MAX_INT beyond 160 then I get a compile error.

For example, if I use the exact values you provide below, it doesn't work.

According to the docs it seems I should be able to set this anywhere from 6 to 3200.

Any ideas on what's causing this?

Thankfully, setting to 160 has dropped the power usage while connected from ~235µA to ~60µA which is good enough for me (although I would like it lower).

Thanks for your help.

Regards,

Gary

RE: Power Usage when connected to nRF Connect Android App

Kazi Afroza Sultana — Fri, 05 Aug 2022 14:47:08 GMT

Hello Gary,

The following configs set the preferred connection interval:

CONFIG_BT_PERIPHERAL_PREF_MIN_INT=3100

CONFIG_BT_PERIPHERAL_PREF_MAX_INT=3200

However as you said that the peripheral can only have preferred connection interval settings. It is always the central that decides what you actually get.

Regarding nRF Connect for android app, you can read this link https://stackoverflow.com/questions/21398766/android-ble-connection-time-interval . It is possible to choose between a few intervals, but you are not free to set it to any value that you want.

''I also have another question related to the connection timeout for the nRF Connect Android App.

If I set my advertising interval on my peripheral to 2 seconds the app connects reliably. If I set it to 3 seconds then sometimes it connects but sometimes it times out. If I set it to 5 seconds then it never seems to connect. Is there a specific connection timeout in the app? Is there a way for me to adjust this?''

If the advertising is slow then there is a higher chance that the central will not pick the advertising packets up.

You can read the following blog post:

https://devzone.nordicsemi.com/guides/short-range-guides/b/bluetooth-low-energy/posts/bluetooth-smart-and-the-nordics-softdevices-part-1

Thanks.

Best Regards,

Kazi Afroza Sultana