BLE - HID profile

RE: BLE - HID profile

ovrebekk — Mon, 20 Dec 2021 09:36:09 GMT

This article discusses some different ways of having your app looking for a BLE device in the background, even if the uses closes the app on the phone side.

The best method is to use a foreground service, which will show a persistent message on the notification bar informing the user that your app is still looking for BLE devices in the background.

Similar functionality should also be possible on iOS, as discussed here.

Best regards
Torbjørn

RE: BLE - HID profile

Roei — Fri, 17 Dec 2021 09:12:57 GMT

Hi,

I'm using my nrf device as a peripheral medical device.

When bonding to my phone, I'm starting advertise, the mobile app sends a connection request, connection is established and we are bonded. That happens when the mobile app is running.

After disconnection, I want to connect again when specific conditions occur. So my nrf device starts advertise with whitelist. Am I doing it correctly from peripheral side?

On mobile side - app isn't running, so I can't scan and send a connection request.

Can you please tell me what do you think?

Thanks!

RE: BLE - HID profile

ovrebekk — Fri, 17 Dec 2021 08:51:23 GMT

It is true that HID devices connects to phones on a system level, rather than through a specific app, since HID devices like keyboards, mice and gamepads usually work across all apps on the phone.

That being said it should be possible for an app to connect to your device even if the app is not active, as long as it is running in the background. Most phones allow you to do so called background scanning, which means an app can look for a device in the background and connect to it when it comes into range.

Can you let me know what you are planning to use your device for?

Depending on what kind of data or services you need I am not sure HID is the best option.

Best regards
Torbjørn

RE: BLE - HID profile

Roei — Thu, 16 Dec 2021 09:01:14 GMT

Hi,

I will tell you what exactly is my requirement.

I'm using BLE to connect to a mobile phone. After bonding - I want to reconnect again. When I start advertising - I'm able to connect to the mobile again only when mobile app is open. When it's closed - no connection is established.

I understand that HID profile implementation may solve that issue, and allow me to establish connection when starting advertising and mobile app isn't open.

Are you familiar with that?

Thanks!

RE: BLE - HID profile

ovrebekk — Thu, 16 Dec 2021 08:56:00 GMT

That sounds odd. Most of the HID related BLE configuration, such as the setup of the HID service, is handled by the ble_hids.c file. Did you take a look at this one?

There is also a lot of BLE handling in the main file, such as the SoftDevice initialization, gap and gatt init, configuration of advertising and services, and init of the conn params and peer manager modules which are also used to service the BLE functionality.

For more information about these examples you can also have a look at the example documentation.

Best regards
Torbjørn

RE: BLE - HID profile

Roei — Wed, 15 Dec 2021 08:01:33 GMT

Hi,

I've reviewed those examples and I didn't see any special BLE implementations, except for the direct advertising. Am I missing something?

Thanks!!

RE: BLE - HID profile

ovrebekk — Tue, 14 Dec 2021 08:44:16 GMT

In the nRF5 SDK we have two examples showing how to run HID over BLE (also called HID over GATT), the ble_app_hids_keyboard and the ble_app_hids_mouse examples.

I would suggest starting with one of these, and make any modifications that you might need based on the standard example.

If you are starting a new design I would also recommend looking into the nRF Connect SDK instead. This is a more future proof software platform which is the one being used for all new Nordic products, and at some point in the future it will not be possible to qualify new products based on the nRF5 SDK.

There are examples for HID keyboard and mouse using Bluetooth in this SDK also.

Best regards
Torbjørn

RE: BLE - HID profile

Roei — Mon, 13 Dec 2021 12:09:54 GMT

Hi,

I'm using nRF SDK.

Thanks!

RE: BLE - HID profile

ovrebekk — Mon, 13 Dec 2021 10:29:45 GMT

Are you planning to use the nRF5 SDK or the nRF Connect SDK for your software development?

Best regards
Torbjørn