nrf528xx Optimal Advertising Intervals

[apaul88]

I am working on a low power peripheral project (similar to the Nordic blePeripheral/uart example). I'm going to be using an nRF52805 with SDK 17 and s112. I found the Apple/iOS recomended advertising intervals of:

• 20ms
• 40ms
• 152.5ms
• 546.25ms
• 1285ms

Has anyone had success with larger intervals (2s, 5s, 10s)? If so, what exact timing have you found to be the most successful with mobile phones (apple/android)?

Thank you,

[ovrebekk]

Hi 

We haven't done any extensive testing on this in Nordic, but maybe someone in the community has some experiences to share. 

What I would say in general is that increasing the advertising interval beyond the official recommendations is a bit risky, as you could get very unpredictable connection times. 

The phones try to scan for advertise packets as little as possible to save power, and if you advertise at a slow rate and you are unlucky you might have to send a lot of advertise packets until you happen to be advertising at the same time as the phone is scanning. 

If your application is fine with this, and you don't mind having to wait for several minutes before a connection is established, maybe this is not an issue, but if a slow connection time will lead to a bad user experience I would advice caution. 

Best regards
Torbjørn

[apaul88]

Thank you for your prompt response. Your description makes sense. I'm sure my application is pretty typical, in that I want to achieve low-power, with a solution that will only be connected to about 1 per month. But when it's time to connect to it, I would like to not need the user to press any buttons, triggers etc. Just walk by, and connect from our Mobile App running on their mobile device.

If anyone else has gotten creative to solve a similar problem, I would love to hear them. 

[ovrebekk]

Hi 

How low power do you need?

As you can see from the online power profiler you can get down to around 10uA average current when advertising 20 bytes every 1285ms, which might be sufficient for your application?

Best regards
Torbjørn