I am new to android.I have Raspberry pi 3 device.I can connect mobile device to Raspberry pi 3 over classic Bluetooth.now i am confused about Raspberry how to connect mobile device to Raspberry over bluetooth low energy.we can connect BLE device to android device and get Characteristics and can write Characteristics.now i want to do same thing in Raspberry pi 3 like (heart rate monitor,MI band 2)
Do it using a program
You can do it programmatically using DBus Calls. DBus is an interprocess Communication method used in linux. You can use DBus bindings for different languages such as python or C to make the DBus calls and do the operations.
A few links to help you get started :
DBus tutorial - https://dbus.freedesktop.org/doc/dbus-tutorial.html
BLE DBus API - https://elinux.org/images/3/32/Doing_Bluetooth_Low_Energy_on_Linux.pdf
Using Gatttool from terminal
Gatttool is a terminal tool just like hcitool. You can use the following commands to get the thing working:
hcitool lescan Gives you the list of nearby Low Energy Devices
gatttool -b mac_adress_of_le_device -I gives you an interactive session with the mentioned LE device
From the interactive session give connect to connect to the device
primary to get the primary services.
From this result, you can use the handle values to get the list of characteristics of a specific service. characteristics handle
To get the value of a characteristic use char-read-hnd handle
To get the characteristic descriptor, use char-desc handle
to write to a characteristic char-write-req handle value
Hope This helps!
Related
I am working with BLE devices. and using nrf controller with bluez 5.4 code.
I am customizing gatttool source code so that multiple devices can connect and disconnect.
My focus part for now is how to disconnect ble device using gatttool apis.
I had found one solution in code that we can use:
g_io_channel_shutdown();
g_io_channel_unref();
These 2 APIs are use to disconnect ble device.
I am using nrf connect application in my mobile to connect generate dummy ble device so that I can perform operations.
When I use this for disconnecting device any other formalities are needed in between or only these APIs are ok?
I am not able to disconnect using these APIs.Some time it is give effect and some time it is not working.
If any one have idea abut this please respond.
Thanks in advance.
Do you mean Bluez 5.4 or Bluez 5.40? Either way, they are quite old releases.
gatttool is one of the BlueZ tools that has been deprecated in BlueZ.
Ideally you would be using the BlueZ DBus API to interact with BlueZ.
Not sure if you are creating a GATT Server (peripheral device) or GATT client (Central Device) but there are examples of both in the BlueZ source:
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
These examples are in Python, but most languages have DBus libraries to help access the API which are documented at:
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/adapter-api.txt
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/device-api.txt
https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/gatt-api.txt
I have created a BLE peripheral that exposes a GATT service. It uses BlueZ 5.50, but it seems that only one device can connect to the GATT service. When the device is connected, then other devices can't see it anymore. It's not showing up in a scan anymore and if it was already scanned, then I can't connect to it anymore.
It seems to be a limitation or configuration issue in BlueZ, because when using the Paypal GATT library it can handle multiple connections. As far as I know, the RPi3 BLE chip should be able to handle up to 10 connections.
Does anyone know if this can be done using BlueZ?
The Paypal GATT library directly connects to the HCI device and bypasses most of the kernel stuff. BlueZ depends on kernel drivers and user-space applications and is capable if the driver reports that the controller allows multiple connections. You need a decent BLE controller and a recent kernel to make it work.
More information can be found in https://github.com/bluez/bluez/issues/12.
I have been trying for a few weeks to connect to the MI Band 2 watch, and read the heart rate characteristic value, but without luck.
I am a little unsure what the procedure is, when we are talking about GATT.
For the API https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/gatt-api.txt I was thinking about using the org.bluez.GattCharacteristic1 interface to read a value out.
I can connect and pair the watch, and get all UUIDs (services, descriptors and characteristics). The heart rate measurement has the following info:
Characteristic
/org/bluez/hci0/dev_CD_1D_69_25_19_5E/service0027/char0028
00002a37-0000-1000-8000-00805f9b34fb
I have tried using the bluetoothctl program to read the value, but getting a "not permitted" feedback.
What is the procedure to read out a characteristic value, using the GATT API.
Your device is using the adopted Heart Rate profile, seeing that 0x2A37 is the adopted characteristic UUID for heart rate measurement. I would recommend that you use the BlueZ command line tools as follows:-
1. Find the handle of the heart rate characteristic using:-
gatttool -b 00:11:22:33:44:55 --characteristics
Replace 00:11:22:33:44:55 with the Bluetooth address of your device. You basically want to find the uuid that contains 2a37 and note down its corresponding 'char value handle'.
2. Find the descriptors at that handle using:-
gatttool -b 00:11:22:33:44:55 char-desc --handle=0xXX
Where XX is the char value handle that you noted down earlier. You should be able to see a couple of characteristic descriptors at that handle. Note down the char handle with uuid 2902.
3- Enable notifications by writing '0100' at that handle using:-
gatttool -b 00:11:22:33:44:55 --sec-level=high --char-write --handle=0xYYYY --value=0100
Where 0xYYYY is the handle of the CCCD descriptor that you noted in step 2. Once this happens, you should start getting indication data, which you can decipher using the temperature data structure found here.
You can find more information about using the BlueZ commands at the following links:-
How can I connect to the FitBit Zip over Bluetooth 4.0 LE on Linux with bluez?
Bluetooth Low Energy: listening for notifications/indications in linux
Using Bluetooth low energy in linux command line
I hope this helps.
Maybe you could try the shell program gatttool or use app like nRF Connect to read.
I got a Microchip RN4871 BLE Module and want it to act as beacon.
So, I connected over UART and executed the following commands:
SS,20
SC,2
NB,09,656667
I am able to scan and connect to it using hcitool and gattool command. Now I want to verify whether the beacon functionality is working or not. I mean the device is periodically broadcasting Beacon packets or not..
How can I verify that.. Is there any android application which can help or can i do with raspberry pi 3 as it has in built Bluetooth Chip
There are some really nice apps from nordic for free available. I like the nrF connect app. I guess it will help you.
My goal is to activate a notification on a Bluetooth Low Energy device to receive data using the DBus Interface so I downloaded the last Bluez version (5.33).
I read the README file and I used the --enable-experimental options
during the configuration.
Now I can only scan for the LE device and connect with it using the Adpeter1 and Device1 interfaces. In the next step I need to connect to the GATTService interface on the device but using d-feet I can't see this interface.
You need to start bluetoothd with the -E (experimental) option.