Reconnect Automatically after bonding

[swathi p]

Hi,

In my application,for the first time device (nrf52832)will start advertising and on nrfconnect for mobile application side we make it get connected and bonded.It may get disconnected, after certain functionality or due to bluetooth disable or battery down.for the next time when i try to connect, if device is advertising as it is already bonded then I must be able to connect automatically  from nrfconnect for mobile app.

For my requirement ,development to be done on application side(device) or nrfconnect for mobile?If it is to be done on application side please let me know how it can be implemented?Is there any example already present is SDK15.3.0 serving the above purpose?If yes, please let me know in which example it is done?

My attempts to solve above involved trying CTS example where it is using whitelisting for the next connection.But there user has to manually connect. Whitelisting provides chance of skipping scanning functionality in CTS example.Did I understand it right?If yes,along with skipping scanning functionality after once getting bonded I always want to get connected automatically if device is advertising.

Thank you.

[Amanda Hsieh]

Hi, 

The Central BLE Heart Rate Collector Example implements bonding and whitelist. You can find the example in the folder <SDK_InstallFolder>\examples\ble_central\ble_app_hrs_c. In order to Initiate bonding the central calls the function pm_conn_secure()

-Amanda H.

[swathi p]

Thank you for your response.As per your suggestion I thought  of going through implementation by testing BLE Heart Rate Collector Example but In testing procedure it is mentioned that two boards are required.I have only one DK.And more likely In my requirement I should be able to test using one DK(advertising) and nRFConnect(scanning) mobile app.Is that possible to test?If yes, let me know how it can be done?If no,please Guide me how to approach for such implementation.

[Amanda Hsieh]

Hi, 

Those instructions are for nRF Connect for Desktop. If you want to test with mobile phones, you should use the nRF Toolbox app. Please see nRF5 SDK v15.3.0: Heart Rate Application:

Test the Heart Rate Application with the nRF Toolbox app, which is available on both iOS (App Store) and Android (Google Play).

-Amanda 

[swathi p]

Thank you for your response.Even in nRF Toolbox I didn't find security settings.

[Amanda Hsieh]

Hi,

nRF Toolbox does not initiate bonding, but the Android  API allows for this for Bluetooth. The bonding is managed by the system, so it is the phone that bonds, not any app. Once bonded, all apps can see this device as bonded.

There's no way to select what type of bonding should be used. The system picks the most secure option based on device capabilities.

-Amanda 

[swathi p]

Hi,

Thank You for your explanation.In testing procedure it is mentioned that we can test it using nRF Toolbox or nRF Connect.As per your suggestion  heart rate application does automatic reconnection if once it is bonded (involving 1DK and mobile).I just want to test and observe how implementation of automatic reconnection can be done.Please suggest how to follow the test procedure or guide me by letting me know the approach for implementing automatic reconnection if device is once bonded.

Thank You.

 

[Amanda Hsieh]

Hi, 

Usually, the Android API will pop up a window to ask to bond or reject. The bonding is managed by the system, so it is the phone that bonds, not any app. Once bonded, all apps can see this device as bonded.

If Android API does not ask to bond, you could open nRF Connect for mobile to initiate a bond after connecting to the device. 

      

If it is bonded successfully, you can see as:

For the implementation, you can refer to the <nRF5_SDK>\examples\ble_peripheral\ble_app_hrs and Peer Manager/ Usage

Enjoy!

-Amanda 

[swathi p]

Hi, 

Thanks for your clear explanation.Present my implementation part is on automatic reconnection if device is once bonded, my question is not about how to get bonded to device.Iam able to bond ,I already followed the same steps you mentioned inorder to get bonded.Thats not the issue.

In Heart Rate Collector Example it is clearly mentioned that device gets automatically connected even after disconnection but it can be tested using 2 DK's.In order to test similar functionality using 1 DK and one mobile As per your suggestion  I tried testing heart rate example but I am stuck at finding security settings.Is bonding is enough to get automatically connected after disconnetion?

Thank you.

[Amanda Hsieh]

Hi, 

There is no security setting in the nRF Connect mobile, but the bond function is enough for the security. 

 "When you choose "autoConnect" with the nrf Connect app, the Android will try to establish connection whenever the device is in range". (source: Q&A page from the nRF connect app)  

Have you tested this functionality? You could see the nRF Connect autoconnect to the device if you turn off and on the power on DK.

-Amanda H.