nRF51 BLE performance issues with Raspberry Pi B+

RE: nRF51 BLE performance issues with Raspberry Pi B+

bjorn-spockeli — Fri, 27 Sep 2019 07:44:35 GMT

Hi PG,

if the matching network for the antenna of the custom boards has not been tuned then that could be the reason for the reduced range, i.e. that you have losses in the RF path that reduce the radiated output power.

However, I am glad that you now have a satisfactory solution.

Best regards

Bjørn

RE: nRF51 BLE performance issues with Raspberry Pi B+

Paul — Thu, 26 Sep 2019 18:32:58 GMT

Hi Bjorn,

Thanks for your reply. We figured out how to make the connection more reliable. The issue was that the raspberry pi was setting the connection rate a little longer (~48ms) and the supervisor timeout a little shorter (~450ms) than other central devices we had been using (iOS devices) and so we had very few (~9) connection interval in order to keep the connection alive at longer ranges.

I'm still not 100% sure why our "custom" Nordic devices had shorter rang than other devices. An nrf51 DK we have also had shorter range, but a Nordic "Thingy" we tested had longer range (nRF52 I believe).

But for now the crisis is averted. We have a satisfactory solution by increasing the supervisor timeout and making the connection interval a little faster.

Cheers!
PG

RE: nRF51 BLE performance issues with Raspberry Pi B+

bjorn-spockeli — Fri, 13 Sep 2019 09:17:11 GMT

HI Paul,

[quote user=""]But I find that the bluetooth range is very diminished when talking to my Nordic nRF51 and nRF52 devices.[/quote]

Are these custom nRF5x devices or are you using nRF5x DKs? If its the first, have you submitted schematics and layout for review of the RF section?

[quote user=""]My BLE sniffer shows the channel map shrinking as well, so I suspect interference is involved, but it seems isolated to the nRF devices.[/quote]

Please attach the sniffer trace, then we can look at the RSSI values and number of re-transmits etc.

Best regards

Bjørn