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I'm using a TI Launchpad, together with the nRF Connect application on my Samsung Galaxy S21. I've got the launchpad connected to my computer and I'm using TI's bTool to send BLE Commands. My phone is the peripheral, while the TI Launchpad is the central.

What I'm trying to do is to look for a service in the nRF Connect app, which sends notifications to my TI Launchpad, whenever the value of a characteristic is changed (not like a heart rate monitor that notifies you periodically).

I read some things about the Battery Service and thought that may be the best option for me. I've added such a service using the "Configure GATT Server" section on my nRF Connect app. I've also added a Battery Level characteristic with NOTIFY properties, and a descriptor called "Client Characteristic Configuration" has been automatically added.

Now, I'm connecting to my phone using bTool. After the connection, I'm trying to change the value of the "Battery Level" characteristic (directly from the app - the "SERVER" section), while sending a notification on my TI Launchpad. It works. But unfortunately, it works even if I didn't enable notifications on my bTool. The notifications are sent even if I didn't write 00:01 to subscribe to the service's notifications.

Screenshot from nRF Connect

Whenever I'm pressing that button and adding a new value, notifications are sent no matter if I set the descriptor value to 00:00 or 00:01(notifications disabled/enabled).

Why is this happening? Also, do you have any other suggestion for a service that sends notifications whenever a value is changed? I'm pretty sure Battery Service is not the best option.

Michael Kotzjan
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Mario Mateaș
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    To answer your second question: You can define any custom characteristic with notification capabilities. But your options are of course limited when using nRF Connect instead of your own custom app. What is your specific use case for this? – Michael Kotzjan Oct 18 '21 at 09:35
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    @Michael Kotzjan not really a specific use, but I'm just trying to create a service that notifies you whenever I change the value of its characteristic. Problem is, notifications are sent even if they are disabled from the client. I've also added an image and updated the post – Mario Mateaș Oct 18 '21 at 09:55
  • This could be a problem of either bTool or nRF Connect. Do you have another phone to check the service using nRF Connect from it? – Michael Kotzjan Oct 18 '21 at 11:57

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