gatt | Go package for building Bluetooth Low Energy peripherals | Networking library

by paypal Go Version: Current License: BSD-3-Clause

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kandi X-RAY | gatt Summary

gatt is a Go library typically used in Networking applications. gatt has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can download it from GitHub.

Gatt (Generic Attribute Profile) is the protocol used to write BLE peripherals (servers) and centrals (clients). As a peripheral, you can create services, characteristics, and descriptors, advertise, accept connections, and handle requests. As a central, you can scan, connect, discover services, and make requests.

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Quality

Security

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Support

gatt has a medium active ecosystem.

It has 1074 star(s) with 290 fork(s). There are 52 watchers for this library.

It had no major release in the last 6 months.

There are 38 open issues and 22 have been closed. On average issues are closed in 243 days. There are 13 open pull requests and 0 closed requests.

It has a neutral sentiment in the developer community.

The latest version of gatt is current.

Quality

gatt has 0 bugs and 0 code smells.

Security

gatt has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.

gatt code analysis shows 0 unresolved vulnerabilities.

There are 0 security hotspots that need review.

License

gatt is licensed under the BSD-3-Clause License. This license is Permissive.

Permissive licenses have the least restrictions, and you can use them in most projects.

Reuse

gatt releases are not available. You will need to build from source code and install.

Installation instructions, examples and code snippets are available.

It has 6124 lines of code, 515 functions and 55 files.

It has low code complexity. Code complexity directly impacts maintainability of the code.

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gatt Key Features

No Key Features are available at this moment for gatt.

gatt Examples and Code Snippets

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Community Discussions

Trending Discussions on gatt

Handling Notifications on Android with Multiple BLE Peripheral Connections

Get success or failure response from Bluetooth-le write

How to get a response from the async write function in capacitor-community / bluetooth-le

UWP Bluetooth LE FromIdAsync Access is Denied Exception

Adding randomized attributes to graph edges

Initialize a null safe variable without a default constructor?

Easy 'for loop' for datetime field not working in Django(google chart)

Bluetooth Advertising Data

regular expression that can scrape all data within a tag

How to restore esp32 connections to gatt server

QUESTION

Handling Notifications on Android with Multiple BLE Peripheral Connections

Asked 2022-Mar-28 at 12:57

So, I am new to Android development and I am trying to connect my device to multiple BLE devices (T-Wristband) to receive frequent notifications (IMU sensor data less than 20 bytes at 50Hz).

When connecting to multiple devices, I miss data from one or more devices. I suspect the reason is that my BluetoothGattCallback method, onCharacteristicChanged, is working on the same thread for all devices (Note: I have checked that by logging Thread.currentThread.getName()).

What I have tried:

1. Android 4.3: How to connect to multiple Bluetooth Low Energy devices

I suspect everyone adding delays is just allowing the BLE system to complete the action you have asked before you submit another one.

Problem: I cannot add delays when receiving notifications since it would interfere with my sampling rate, and I am not sure when I might receive new notifications from another device, or even the same device.

2. Android BLE multiple connections

To achieve multiple BLE connections you have to store multiple BluetoothGatt objects and use those objects for a different device.

In this regard: I have tried writing a custom class for my device, TTGODevice, which saves an instance of the corresponding BluetoothGatt upon connection:

...

ANSWER

Answered 2022-Mar-28 at 12:57

It seems that BLE on Android cannot handle sampling rates at 50Hz and higher. I am not sure if this is a BLE-related problem or if it has something to do with the onCharacteristicCHanged method being called too frequently. I solved this by sending larger packets of data every 50ms, contrary to my original case at every 20ms. Larger BLE data packets are possible starting from Bluetooth 4.2, which is controlled using the MTU, Maximum Throughput Unit. This blog helped me a lot in understanding the underlying mechanism.

When receiving large packets of data over BLE at high sampling rates, it is best to use gatt.requestMtu(MY_DESIRED_MTU) with MY_DESIRED_MTU > 20Bytes inside the corresponding BluetoothGattCallback on Android. It should be noted that larger MTU means it takes longer for the data to be written on the BLE characteristic for the server device.

In short, I am using larger data packets and a larger delay to make up for the limitations in the sampling rate. For a sampling rate of 100Hz on the IMU in the T-Wristband, I am using an MTU of 95 Bytes, requested by the Android device, and a 50ms delay on the timer on the T-Wristband. This allows me to receive five consecutive data samples every 50ms.

Source https://stackoverflow.com/questions/70177244

QUESTION

Get success or failure response from Bluetooth-le write

Asked 2022-Mar-26 at 20:19

I'm using the Bluetooth-LE community plugin in a Ionic React project.

I'm writing a value to the GATT server with the following code:

...

ANSWER

Answered 2022-Mar-17 at 22:36

I need to be able to set a flag variable to indicate whether the write was a success or failure. There is nothing in the docs to indicate how this can be done.

You linked/shared right what the docs say is returned.

Source https://stackoverflow.com/questions/71518680

QUESTION

How to get a response from the async write function in capacitor-community / bluetooth-le

Asked 2022-Mar-18 at 01:42

I'm working with an ESP32 chip and am trying to create an Android app (using Ionic) which allows user to send wifi credentials to the ESP32 chip via BLE. I'd like to be able to update the status of the wifi sending process for the user in the UI (which I'm developing using Angular and then converting it to an Android webapp using Ionic). To do this, I'm also using the capacitor-community/bluetooth-le library.

Can anyone explain to me what this.queue does in the async write function (code shown below) does? I thought this function returns a response from a remote BLE device after writing to a GATT characteristic, but I get absolutely nothing at all for a response.

...

ANSWER

Answered 2022-Mar-18 at 01:42

Here's how I'm using BleClient.write to transmit information to a BLE device (recipient):

Source https://stackoverflow.com/questions/70366455

QUESTION

UWP Bluetooth LE FromIdAsync Access is Denied Exception

Asked 2022-Jan-27 at 15:53

I am following the code on this page:

https://docs.microsoft.com/en-us/windows/uwp/devices-sensors/gatt-client

It shows simply scanning for devices and then calling FromIdAsync to get the device, but as soon as I call that method I get an exception from the bluetooth dll saying "Access is Denied".

I then found another post when I did a search for FromIdAsync and Access is Denied and it included this code:

...

ANSWER

Answered 2022-Jan-27 at 15:53

It looks like the issue has something to do with Unity not including the bluetooth capability when building directly from Unity and running.

When I built the project and then loaded it into Visual Studio and executed it there, I did not get any errors.

So that will be my plan....build and then open in Visual Studio.

Source https://stackoverflow.com/questions/70873512

QUESTION

Adding randomized attributes to graph edges

Asked 2022-Jan-07 at 05:32

I've tried to add, randomly, one of two values of attribute in a dict, to each edge of some listed graphs, through the following code:

...

ANSWER

Answered 2022-Jan-07 at 05:32

You do not construct the dictionary for the function set_edge_attributes correctly (and, in general, use too many non-Pythonic features in your code). Here is a correct (and improved) solution:

Source https://stackoverflow.com/questions/70616868

QUESTION

Initialize a null safe variable without a default constructor?

Asked 2021-Nov-12 at 08:13

I'm sure this problem has been asked before, but I can't figure out how to even properly word it.

I am trying to get Bluetooth Device data into my flutter app. The examples I have found either use non-null safe versions of dart code or they hide all of the important details.

I am trying to build a very simple prototype from scratch so I can get a better grasp on things.

I want to make a stateful widget that updates based on notifyListeners(). The idea is I start out with "noName bluetooth device", then once I have a device connected, I can update the object and display the name of the connected device.

I keep running into this same roadblock and I can't get past it. I want to make a default Bluetooth Device, but the device has no default constructor. The default device cannot be null because of null safety.

Can someone help me figure this out. There is something I know I am fundamentally misunderstanding, but I don't know where to start.

The code below makes a ChangeNotifierProvider the parent of my BlueTesting widget that should display details of the connected Bluetooth Device (I haven't written all of the code yet).

The BTDevices class should update the Bluetooth Device object, and notify the app to display the updated data from "the default empty device" to the new connected device.

Thank you for your help!

...

ANSWER

Answered 2021-Nov-11 at 19:52

Make your variable nullable BluetoothDevice? device; And check if device is null later

Source https://stackoverflow.com/questions/69933530

QUESTION

Easy 'for loop' for datetime field not working in Django(google chart)

Asked 2021-Oct-26 at 06:26

I'm trying to use google chart in my Django project, the google chart required a format like ['label1', 'label2', 'label3', new Date(Y, m, d), new Date(Y, m, d), null, 100, null], it's like a list, so I'm trying to keep things simple first, I only replaced the date with template tags and leave other fields as default. The template tage works well alone in P element and output result as "2014, 10, 12". I would really appreciate it if someone can have a look, cheers.

views.py

...

ANSWER

Answered 2021-Oct-26 at 03:16

You're mixing your for loop into your data types which may be your issue. I think you'd be better off with something like this:

Source https://stackoverflow.com/questions/69716413

QUESTION

Bluetooth Advertising Data

Asked 2021-Sep-20 at 15:11

I was trying to understand basics of Bluetooth. I have few queries regarding the scanning and advertising of classic and low energy Bluetooth.

Is EIR data (classic Bluetooth extended inquiry response) and AD data (Bluetooth low energy scan response) read from GAP profile. Where is data from GAP profile stored? Is it on host or controller?
Is there a different GAP profile for classic and different GAP profile for LE ?
When we enable advertising (low energy) using hcitool cmd or enable discoverable mode (classic Bluetooth), how does controller get all the advertisement information (scan response/ extended inquiry response)? Is it stored on controller?
As mentioned in Bluetooth Specification 4.2 section 7.8.8 LE Set Scan Response Data command can be used to provide data for scanning packets. Is this different than GAP ?
Is Gatt Server running before connection is formed ? If not, then how is GAP profile (used for advertising) relevant before connection ?
Can same fields (e.g. device name) from EIR data and AD data be different ?

...

ANSWER

Answered 2021-Sep-20 at 15:11

Yes, both EIR and AD elements are defined by the GAP profile. This is managed in the host.
No, the same GAP profile is applicable to both classic and BLE. However, a device can support either one or both. What I mean by this is that if you have a Classic-only device, then the qualification will be against the classic GAP profile, while if you have and LE-only device, then the qualification will be against an LE-only GAP profile. In other words, in terms of Bluetooth qualification both the GAP profiles appear to be separate, but on the device itself it is one GAP profile.
Theoretically, GAP-related information is managed on the host layer, and this is then passed to/from the lower layers (see figure from Bluetooth Core Specification below). The controller then takes the information and sends it out in the packet format specified for EIR/AD data by the Bluetooth specification.

This depends on what you mean by GAP? To avoid confusion, GAP can be a service sitting in your GATT table, but this is not exactly the same as the GAP profile. The GAP service that sits in the GATT table is a subset of the GAP profile in that it contains some information about the GAP profile but is not a 1:1 direct reflection. The Scan Response data itself is defined by the GAP profile, but it is usually not included in the GAP service. Below is a list of all of the mandatory/optional fields for the Scan Response Data (SRD). You can find this and more information in the Supplement to the Core Specification.

Yes, the GATT server (also known as GATT table) should be formed before a connection is made. However, the GATT table can be updated when a connection has already been made. Again in this case I believe you are referring to the GAP service which is slightly different from the GAP profile.
No, fields that are the same in the EIR/AD data should have the same value. This is reflected in the description of the device name in Core Bluetooth Specification v5.3, Vol 3, Part C, Section 3.2.2.1.1:-

A BR/EDR/LE device type shall have a single Bluetooth Device Name which shall be identical irrespective of the physical channel used to perform the name discovery procedure.

If you haven't done so already, I highly recommend reading the Bluetooth Core Specification v5.3, Vol 3, Part C (page 1230) - GENERIC ACCESS PROFILE, as it will have answers to all of these questions and more.

Below are some additional useful resources:-

Source https://stackoverflow.com/questions/69159353

QUESTION

regular expression that can scrape all data within a tag

Asked 2021-Aug-17 at 12:24

please forgive my mistakes, add comment for any doubt

i was trying to scrape the data which is either contained in h2 and bold tag starting with a number from various blogs through regex, but i am getting only starting words of the sentence instead of full headline by using this regular expression

...

ANSWER

Answered 2021-Aug-17 at 10:34

this can be done by newspaper library

Source https://stackoverflow.com/questions/68811897

QUESTION

How to restore esp32 connections to gatt server

Asked 2021-Aug-04 at 23:39

I'm building some IoT devices which are controlled by ESP32. I want to have real time control via Android application. Because WiFi is too power hungry (my devices are battery powered) I've decided to connect using BLE which should be more suitable option.

I have Xamarin Android app which acts as a GATT server because it allows for multiple devices connected and aggregated in my app. ESP32 device connects to the server when I advertise and properly receives notifications for example when I click the button. The problem is that I have no idea how to manage the situation when user exits the app. How to restore the connections? It is no problem to save some deviceId in local db on the android device but can anyone tell me what steps should I take to achieve following results:

User connects app to the device, exits the app or leave the ble range and when he opens it again connection is restored and user can send some data to the device.

On ESP32 there seems to be no reconnect option and on android theoretically there is but when device is not a server but client (autoconnect = true) Maybe I did it the wrong way (devices should be servers but is then possible to be connected to multiple devices and achieve results of real time control?)

I will appreciate any advices :)

...

ANSWER

Answered 2021-Aug-02 at 06:22

With BLE you cannot initiate a connection from a peripheral device. The central device is responsible for initiating and maintaining the connection. As such, you have two options to achieve what you want:-

Option 1: as you said, switch the roles so that the Android device is the central in the connection. This way you can set autoconnect = true and this might be the easier option.

Option 2: maintain the roles, but add code on the ESP32 side so that upon disconnection, the ESP32 switches to a continuous scanning mode where it searches for the Android device, and as soon as it finds it, it would reconnect. If you want to save battery on the ESP32 then you can have it go to sleep and only wake up periodically to do a quick scan in case the Android device became available again.

Source https://stackoverflow.com/questions/68614591

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