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Questions tagged [bluetooth-gatt]

The Generic Attribute Profile (GATT) defines the way that two Bluetooth Low Energy (BTLE) devices transfer data back and forth using concepts called Services and Characteristics.

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Connection and notification in Bluetooth Low Energy (BLE) GATT Profiles

As stated here, a BLE GATT client can "subscribe" to a specific characteristic in a GATT server to be notified each time a change occurs within this characteristic. Actually I'm wondering, does the notifying characteristic keep alive the connexion…
sc4re
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Read temperature from nRF 51822 with sensor HTS221 via bluetooth

I am trying to read temperature from this little sensor https://www.aliexpress.com/item/temperature-sensor-and-humidity-sensor-HTS221/32953862359.html?spm=a2g0s.9042311.0.0.e3534c4dT9GRz3 There are 4 GattServices available GattService…
maxxxo
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Correct way how to connect to BluetoothGatt devices sequentially

I have already implemented Bluetooth low energy device scanning logic, but I'm struggling a little bit with BluetoothGatt service usage. What I want to do is to connect to each of my ESP32 devices sequentially from my Android phone, so that I can…
Mr. Blond
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Android NordicSemiconductor/Android-BLE-Library onCharacteristicChanged is not called

I'm using this library NordicSemiconductor/Android-BLE-Library for BLE communication and successfully able to connect the peripheral device. I'm getting the services and characteristics and able to write the characteristics. But for somehow after…
Waqar UlHaq
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How to parse BluetoothGattCharacteristic value in java

I'm currently a bit lost in trying to figuring out how to transfer data from my ESP32 microcontroller to android phone. I have managed to send and read characteristics value, but don't know how to parse it.. For now, I'm sending simple integer value…
Mr. Blond
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Is there a conflict between Python gattlib and OpenCV?

I want to create a Python program opening webcam with OpenCV and controlling Bluetooth device with gattlib on Raspberry Pi. Here is the code: import cv2 import threading from gattlib import GATTRequester from time import sleep cap =…
yushulx
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Why BluetoothGattCallback keeps disconecting after a few seconds?

I try to connect to MiBand 2 and keeps the connection, but after a few seconds it fails and reconnect. I scan for the available devices and display them. When I click on the device I want to connect to it connects, but after a few seconds it…
Mary
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web-bluetooth get stored data from device GATT

My goal is to get data stored in device. Like device which is measuring temp or whatever and store it to its memory. i need to query all this data device has via Record Access Control Point (RACP). First thought, to achieve it, was get…
mr.Deepwest
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Clarification of - Attributes, Characteristics, Services and profiles

I'm currently trying to get a better understanding of the BLE protocol and I've some questions regarding the structure of GATT - more specifically with regards to what exactly Attributes, Characteristic and Services. And how these interact and make…
Sorenp
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Separate vs Combined Characteristics in one Gatt

We're trying to determine whether to use separate GATT characteristics or combine multiple properties into one custom characteristic. The benefits of combining is fairly clear: one transaction, many properties. But even with multiple characteristics…
drew covi
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send/receive string via GATT in BLE

I have been successfully sending and receiving hexa values via GATT using "Heart rate service" and with characteristic "Heart Rate Measurement". Now I need to send TX/RX strings over GATT. Can anyone help me out by giving suggestion about: Which…
Loki
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BLE iOS sending data to Android gattServer peripheral:writeValue:forCharacteristic:type not working

I am trying to use android as a BLE peripheral (gatt server). I was able to get it advertising, and I can have the iOS app reeive notifications when certain characteristics are changed, but I am having trouble doing a simple writeValue. On iOS I…
Chase Roberts
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Bluetooth Gatt Connection Issue in Oneplus when device is turned off

I have an issue only in my Oneplus device, where as Pixel, Nokia works great. Here is my issue. I have BLE device and connect to it via my app using following code. public boolean connect(final String address) { if (mBluetoothAdapter == null…
SRBhagwat
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BLE disconnect and close the Gatt, getConnectionState is STATE_CONNECTED, but device connection is still alive

I have a application for controlling multiple Bluetooth LE lamps. When I want to disconnect all devices at same time, I call BluetoothGatt disconnect, and close from onConnectionStateChange, getConnectionState will return STATE_DISCONNECTED, but…
Lucas
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Web bluetooth misses initial notifications

I am using the code in the example https://googlechrome.github.io/samples/web-bluetooth/notifications.html to subscribe to notifications from my bluetooth device. return myCharacteristic.startNotifications().then(_ => { log('> Notifications…
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