Automatically connect with SDK14.2 for HID

[Taylor]

Hi,

   In our application, we are using HID to control mobile phone or PC.When users connected our product, it will automatically connect next time.

But our product is battery powered,so we want to prohibit automatic connection when the battery is low(3.6V Li-battery).

How should I do when battery is low?

The version of SDK is SDK14.2.

[Hung Bui]

Hi Taylor,

You can do what Andrew suggested, to not advertise. 
If you still want the phone/PC to be able to connect but not auto-connect you can think of advertising with different BLE address. This way you can tell the phone/PC about the condition of the device. You can choose to do very long interval advertising when the battery is low.

[Taylor]

Thanks for your reply.

I had set a mode which would not advertising when the battery is low.If the device had connected,I can not disconnect manually,because it had be bonded.

How does the Phone/PC know the condition of the device? We don't have custom service.

[Hung Bui]

What do you meant by "still to connect automatically" ? Would the connection terminated ? 
If the connection terminate, you can just don't restart advertising then the central won't be able to connect to your device.

[awneil]

Taylor said:

the device will still to connect automatically

It's not the device - it's the Central which does that.

And that would be the normal behaviour that users would expect - if your mouse disconnects for some reason, you'd want it to automatically re-connect as soon as possible.

As Hung Bui said, if you don't want the Central to connect, then don't advertise.

[Taylor]

awneil said:

It's not the device - it's the Central which does that.

It's right!

Should I close advertising immediately after using sd_ble_gap_disconnect()?

What can be done with the code?

[Hung Bui]

If you don't do advertising when you are in a connection, you just don't re-start advertising (check in the code if you do re-start advertising after BLE_GAP_EVT_DISCONNECTED event). 

If you already advertise when you are in a connection, you would need to stop that. You can stop it after using sd_ble_gap_disconnect()) 

[Ben_nrf52840]

Hi,

I have the same issue which is connected automatically from the host in HID.

I disconnect by using sd_ble_gap_disconnected() and stop advertising using sd_ble_gap_adv_stop().

I confirmed the advertise is not started automatically in the BLE_GAP_EVT_DISCONNECTED.

I'm using nrf52840 with SD version 17.0.2.

Would you please help to prevent host from connecting automatically?

Regards,

Ben