I am fairly new to the BLE world. Assuming I have a BLE device Eg: A heart rate monitor, How do I interact with that BLE device using C code.
I am able to see the Heart rate data using the command line tool 'bluetoothctl'. If I want connect to the same device through C code and see the Notified data, how do I go about it?
Though some codes on the Internet and GitHub helped me to scan for the device, I do not have any idea on how to connect to the device, read the GATT characteristics of the BLE device. I'd even appreaciate it if anyone points me to the API documentations of BlueZ, I literally have no clue what the programs are all about. Any assistance would be of great help.
The preferred API for BlueZ uses the D-Bus bindings. The documentation for those APIs are at:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc
There are Python examples of how to use the D-Bus API at:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test
bluetoothctl is written in C and the source is available at: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/client
Related
I saw a video about a Pi 0 that has been coded to track the amount of people that are in a location at a certain time to report the data to an app that tell's people if the area is busy. This does not require for the tracked devices to be connected to a wifi.
How would one go by that? Are there specific node modules?
Thank you in advance
The RPi Zero is able to discovery nearby Bluetooth devices if those devices are advertising there presence.
The command line tool bluetoothctl allows you to scan for devices to test this.
To do this with code, BlueZ has a set of APIs which are documented at:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/adapter-api.txt
There is an example of how to discovery with the API using Python at:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test/test-discovery
The BlueZ API uses D-Bus so can be used with any language that has D-Bus bindings.
https://www.freedesktop.org/wiki/Software/DBusBindings/
I never used a raspberry pi before and I have a project part of which includes receiving data from a BLE blood pressure device over Bluetooth to a raspberry pi 3. I can pair the device to my raspberry but I have no idea what to do next. I need to be able to receive the measurements in my raspberry please help and thank you in advance.
PS: the device I'm trying to use is very similar to this one:
https://ibb.co/71365k5
Thanks for your answers, I have tried "Gatt" and "Gatttool" but the problem is after pairing the device is meant to send the measurement to its application on an android phone, without it I cannot read the blood measurement characteristic or it just does not exist.
Linux uses BlueZ as a default bluetooth stack. It exposes DBus APIs for implementing software using Bluetooth.
If you don't want to use this API directly, which can sometimes feel a bit low level you have many libraries that wrap it, such as https://github.com/getsenic/gatt-python that also comes with examples.
All other solutions requires replacing the Bluetooth stack on Linux and hence your other existing Bluetooth pairings to the system will stop working.
I want to implement a BLE in a Raspberry which sends the result of a sensor apart from it's characteristics and make another Raspberry to obtain that data.
Because the language that offers the possibility to read data from the sensor is written in C, C++ and Python, I have been searching through multiple libraries like pygattlib, pygatt, pybluez and bluepy with no result to know how to send data in addition with their characteristics.
Is there any option to reproduce my request?.
I also read about iBeacon and Eddystonne protocol from Apple and Google, however my first point is to comunicate between two Raspberry (server and client).
If you are using rpi you should have Bluez preinstalled. Bluez provides API through D-Bus which you can use to add GAP and GATT functionality. The documentation is in source code of Bluez.
BLE advertising (GAP profile) documentation: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/advertising-api.txt
BLE data transfer (GATT profile) documentation: https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/gatt-api.txt
Of course it easier to have an example. They are in Bluez repo too! They are written in Python but it should be easy to translate it to different language because they are using only D-Bus.
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test/example-gatt-server
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test/example-gatt-client
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/test/example-advertisement
I'll mark this as an answer because I could make it possible with the libraries written in javascript noble and bleno
I have a Raspberry Pi that acts as a BLE peripheral. I want to add Apple's HomeKit Accessory Protocol (HAP) to the Raspberry Pi's BLE code, to control the BLE device using Homekit. I would like to avoid implementing HAP over the internet.
The closest resource I found is https://gist.github.com/KhaosT/6ff09ba71d306d4c1079. However, this gist makes it seem like there are many unknowns with that process.
Does anyone know if this is possible? If so, any info or resources would be greatly appreciated. Thanks!
As mentioned at https://developer.apple.com/homekit/ under Accessory Developers, you need to first sign up for MFi and then you will get access to all the resources you need in order to implement homekit. All source code you can find publicly online is against Apple's license since they prohibit public redistribution of documentation and source code of implementations.
I have a device with a few custom GATT services, and I would like to write a Linux program to interact with it. After some searching I found out that Linux is using BlueZ to handle the Bluetooth LE protocol. I'm using Ubuntu 15.10 with BlueZ 5.35, but I cannot figure out how use this BlueZ from a user-space program. I cannot find an API documentation anywhere, no tutorials, examples, nothing. Is it even possible to use this BlueZ stack to do anything other than just connecting to Bluetooth devices with default services? And if so, where is the documentation? (Preferably C/C++ API but at this point anything goes)
Have a look at attrib/gatttool.c in the bluez sources [1]. Gatttool is a command line utility for connecting to BTLE devices using the C "API". The GATT interface is not exposed in libbluetooth though.
A newer alternative to gatttool and thus another example to learn
from is the btgatt-client, which you can find in
tools/btgatt-client.c (to enable compilation configure bluez with
--enable-experimental).
Besides the C interface bluez integrated a DBUS interface.
bluetoothctl is an example tool using the DBUS interface. The code of
bluetoothctl can be found in client/ [2].
Another example program using the C interface of bluez is the Anki
Drive SDK [3]. It packaged the bluez GATT C interface in its own
library libbzle [4]. When using the C interface you have to connect a
socket when establishing a BTLE connection. The gatttool does this
via the GATT interface, which in turn uses glib iirc. But you can
also do this using syscalls (socket, connect, ...) as explained e.g.
here [5]. This document also explains:
Unfortunately, as of now there is no official API reference to refer to, so more curious readers are advised to download and examine the BlueZ source code.
Gilbert Brault also extracted the GATT interface from bluez [6] and links to a rudimentary doxygen documentation of the GATT interface [7] with the following disclaimer:
This is a work in progress with the intent of documenting all important functions and data structures
Also Szymon Janc gave a nice overview in his talk "Bluetooth on Modern Linux" at the Embedded Linux Conference 2016 [8]. Starting at 42:00 he talks about the unexposed C interface. But in general he seems to recommend the DBUS API (see "Tips" slide at 45:30). Some DBUS documentation can be found in doc/gatt-api.txt [9] and Python examples using the DBUS interface can be found in test/.
Hope this helps.
[1] http://git.kernel.org/cgit/bluetooth/bluez.git/tree/attrib/gatttool.c
[2] http://git.kernel.org/cgit/bluetooth/bluez.git/tree/client/
[3] https://github.com/anki/drive-sdk/
[4] https://github.com/anki/drive-sdk/tree/master/deps/bzle/
[5] https://people.csail.mit.edu/albert/bluez-intro/c404.html
[6] https://github.com/gbrault/gattclient
[7] http://gbrault.github.io/gattclient/index.html
[8] https://www.youtube.com/watch?v=tclS9arLFzk
[9] http://git.kernel.org/cgit/bluetooth/bluez.git/tree/doc/gatt-api.txt
I feel your pain. I needed to add user input from a custom BLE peripheral, a simple remote pushbutton, to an embedded program running under Linux (Stretch) on a Raspberry Pi. I was stunned by the needless complexity and Spartan (not a compliment) documentation of the BlueZ API. All the BlueZ “examples” are written from the perspective that Bluetooth is the center of the universe and the user wants to support every Bluetooth device ever invented. In my case I knew exactly the device, service, and GATT characteristics I needed to interact with, and I wanted a minimum overhead task that would do its thing in a low priority thread.
It turns out a BLE central client is pretty straightforward using BlueZ, but it was an arduous road starting with the source for the BlueZ utility bluetoothctl in release 5.49. I accomplished my needs using only three unmodified source files from the BlueZ distribution and excerpts from an additional three source files. Since the BlueZ source is inextricably dependent on D-Bus and the Gnome GLib main loop, I grudgingly included them.
Following OlivierM's generous lead, and in hopes that my embarrassingly massive investment in time saves someone else a month of their life, I have posted my example Bluetooth BLE client on GitHub: https://github.com/jjjsmit/BluetoothBLEClient
It would arguably be simpler and quicker to write a shell script on Linux to do what you need to do. The BlueZ commands are relatively simple and straightforward, and there are many tutorials and questions on how to use it.
Tutorials:-
http://www.jaredwolff.com/blog/get-started-with-bluetooth-low-energy/
https://learn.adafruit.com/reverse-engineering-a-bluetooth-low-energy-light-bulb/control-with-bluez
https://lilyhack.wordpress.com/2014/02/03/ble-read-write-arduino-raspberry-pi/
http://joost.damad.be/2013/08/experiments-with-bluetooth-low-energy.html
Questions:-
Using Bluetooth low energy in linux command line
Bluetooth Low Energy: listening for notifications/indications in linux
How can I connect to the FitBit Zip over Bluetooth 4.0 LE on Linux with bluez?
Once you are more familiar with using the commands manually you can then write a minimal shell script so that this is automated for you.
I had a similar issue which is to interact with a BLE device with a GATT C/C++ API. I have realized there was no such API existing.
The way I fixed my issue was to write my own GATT library. I have pushed the code on Github: https://github.com/labapart/gattlib
I use this library in my own BLE project and it fulfils my needs. I created few examples https://github.com/labapart/gattlib/tree/master/examples that use the library to encourage people to use it and have better feedback.
I recently found out that Qt has Bluetooth Low Energy support as host since Qt 5.7. Qt Bluetooth LE. It is available under LGPLv3 or commercial license, and exposes a C++ API.