Nordic distance measurement example, devices stop "seeing" each other after a while

[Miguel Roque]

Hello all,

I'm running the distance measurement example from Nordic Connect SDK in MCPD mode, both devices boot, start the adv and scan, connect to each other and start giving measurement results. The problem is that after a while (can be 5min, 10min, 20min...) they stop seeing each other and don't connect again.

Does anyone knows why it happens?

[Simonr]

Hi

There shouldn't be any timeouts trigging in the distance measurement sample by default as far as I know, we've had it running without issues for multiple hours on various showcases, running MCPD and the other parameters for distance measurement. Can you describe more in detail what exactly happens? Does the application print any error messages or disconnect reasons that might help us understand what exactly goes wrong? Are your devices stationary while you're doing these tests or are you moving one or both around to test range for example. What environment and at what ranges are you testing the two devices. Are both devices DKs or custom boards, and how are they powered exactly?

Best regards,

Simon

[venkat92]

I am running into the same issue as well. As Miguel mentioned I see the same behavior. I noticed that this deterioration happens more quickly if there are more devices ranging. I am running MCPD as well. With 3 devices ranging with each other, this behavior is seen only after few hours whereas with 4 devices, I noticed that this behavior is seen within 15 minutes consistently. And the key observation here is that it is not that these devices stop ranging with each other, but one or more of the devices stop seeing the ranging beacons from one or more devices and there is no recovery until the device not seeing/scanning for the ranging beacon is restarted. I confirmed this by monitoring the BLE scan callback. Please let me know if any of you see the same behavior and know a possible fix.

Thanks,

Venkat

[Simonr]

Please provide more information on your test case here. Are these 4 devices DKs or custom boards, what range and test environment are these devices in? The only errors I can recall seeing is a buffer overflow where the logging from the device stops and resetting the device will be sufficient. If multiple devices makes this occur more often it might be related to this.

Best regards,

Simon