Automatically re-connect to the previous bonded device in certain range

RE: Automatically re-connect to the previous bonded device in certain range

MARTIN FR — Tue, 26 Apr 2016 11:07:04 GMT

Hello Hao could you please tell me how you tested the ble_prox exmaple on IOS did you odify some part of source code or you just tested without any modiifcations on the source code

RE: Automatically re-connect to the previous bonded device in certain range

Markus — Mon, 25 Apr 2016 16:49:34 GMT

Hello Hao Tsui,

i am more a newbie than you ... But i want the same as you!

I want to light up a led when the BLE Nano is in Range and Shut down when it is out of Range.

Can you please help me to send your Code?

Thanks alot

Markus

RE: Automatically re-connect to the previous bonded device in certain range

Hao Tsui — Fri, 01 Apr 2016 14:04:33 GMT

Many thanks Kristin !!

RE: Automatically re-connect to the previous bonded device in certain range

FormerMember — Fri, 01 Apr 2016 14:03:13 GMT

You can download the source code for the nRF Toolbox here to check how the re-connection part is implemented.

RE: Automatically re-connect to the previous bonded device in certain range

Hao Tsui — Fri, 01 Apr 2016 13:45:34 GMT

Brillant Kristin! May I ask do you know what should be done on app part, then it would have the re-connect function just like what NRF TOOLBOX is capable of? (maybe this question is more like app development :P )

RE: Automatically re-connect to the previous bonded device in certain range

FormerMember — Fri, 01 Apr 2016 12:14:08 GMT

The nRF Toolbox --> Proximity app is designed to have the proximity functionality, for example re-connect upon a link loss. The lightblue app on the other hand is "simply" an app that allows you to connect to devices and interact with the devices, write, read, notifications, etc. It doesn't know anything about the usecase for the connected peripheral, and it will therefore not automatically reconnect upon a disconnect.

RE: Automatically re-connect to the previous bonded device in certain range

Hao Tsui — Fri, 01 Apr 2016 12:07:34 GMT

Hey, Kristin. It works fine now on NRF TOOLBOX, it will print out the "LINK LOSS ALERT" when iOS far away. and when iOS closer it automatically re-connect! It is cool!

However, when I used LightBlue to test again it did not automatically reconnect. Could you help me to figure out why there is different result testing on LightBlue and nRF toolbox?

RE: Automatically re-connect to the previous bonded device in certain range

Hao Tsui — Fri, 01 Apr 2016 10:37:37 GMT

Thank you Kristin again. However, regarding to question 2. When I tested Proximity on nRF Toolbox, it will generate alert sound when my device(iOS) outside the connecting range. And when it (ios) in the range, the sound ends. It seems fine, however, shouldn't it print out "LINK LOSS ALERT !!!" on RTT whenever my iOS is far away and closer again?

On my RTT it only shows: LINK LOSS ALERT !!! (once! at the beginning i manually pair the device) when I started to testing the proximity range it would not print out "LINK LOSS ALERT" anymore (which I think it should be!)

RE: Automatically re-connect to the previous bonded device in certain range

FormerMember — Fri, 01 Apr 2016 08:28:14 GMT

I have updated the answer to answer question 2 as well.

RE: Automatically re-connect to the previous bonded device in certain range

Hao Tsui — Fri, 01 Apr 2016 08:02:17 GMT

Thank you Kristin :) It is a very clear answer for my question 1.

RE: Automatically re-connect to the previous bonded device in certain range

FormerMember — Fri, 01 Apr 2016 07:59:15 GMT

"LINK LOSS ALERT!!!" will be printed if the reason for the disconnect is a timeout, i.e. the central is out of range and the peripheral doesn't receive any packet within the connection supervision timeout. When the disconnect reason is "timeout", the event BLE_LLS_EVT_LINK_LOSS_ALERT will be triggered, see on_disconnect(..) in ble_lls.c.

"GAP_disconnected" will be printed no matter what the disconnect reason is.

When the central disconnects the link, the reason is be something else than "timeout", and thus, only "GAP_disconnected" will be printed.

For a fast reconnect, provided that the peripheral is within the range of the central, you can use directed advertising with high duty cycle. Directed advertising with high duty cycle does only last for 1.28 s. So if the peripheral initially is out of range of the central, it may be better to use normal advertising with a short advertising interval.

In addition, you have to set up the central device to automatically scan and re-connect upon a disconnection. I would think the Nordic iOS app nRF Toolbox --> proximity do that?