I'm running some of the Python example code from Bluez using the DBUS interface. I am on Fedora 28, Bluez 5.50. The device I am trying to connect to is a dual-mode Microchip BM78. Both the sample code and bluetoothctl will discover the device, show both the LE and BDEDR services, but neither detect the the GATT characterstics once services are resolved. The GATT characteristics are not resolved, even after the device is paired, trusted and/or connected.
The Bluez DBUS API seems to require that the characterists are first discovered before any attempt to read or write is possible.
I can connect to the device using non-DBUS APIs and access the characteristics just fine.
Is there some way to force characteristic discovery once a service is resolved? Or some way to connect to a known characteristic that has not be discovered using the DBUS interface?
Related
I am working on a project with the beagle bone black wireless, where I need to be able to send music control commands to a phone. Note, I don't want to stream music to my beaglebone. I have spent about a week looking online, and found very little about this.
The OS for the beaglebone is Debian Jessie. I can get things like hci0tool, Bluetoothctl, hciconfig to work. I can detect and pair to a device. It seems though that my connection only lasts for the pairing process, and fails every time afterwards.
My current process is executing:
sudo su
bluetoothctl
power on
agent on
default-agent
scan on
I get the mac address
scan off
pair <MAC Address>
trust <MAC Address>
connect <MAC Address>
As of now pairing and trust succeed, though the connection ends after pairing finishes. And I have no idea of where to start for sending a command to a phone.
Connect call on Device1 interface will tries to connect all the profiles supported between the device and adapter. This happens by negotiating or exchanging the supported profiles.
Connection may not be possible when Adapter doesn't support the minimal requirement of profiles which is needed by the Device. In this case, you may need A2DP provider in adapter end to get connection successful. Yes, this is contradictory to this statement.
If you don't want to connect with all the profiles between Device and Adapter, then you can use ConnectProfile method in Device1 interface.
But bluetoothctl doesn't provide commands to achieve neither ConnectProfile nor you AVRCP commands.
You need to use D-Bus calls to get the communication with Bluetoothd. If your application is command line/shell based, you can use dbus-send/gdbus commands to address the D-Bus interface.
Although bluez-tools implements media control AVRCP commands, it doesn't provide any utility which uses it. Either you can compile bluez-tools as library and develop application using the media control API or use dbus-send/gdbus.
I have started with some samples using GDBUS, but not yet for AVRCP controls. See here : https://gist.github.com/parthitce
and Documentation here: https://www.linumiz.com/category/blog/
I'm not a ble guru, I worked on some modules to expose some simple service with pairing and bla bla :9
One of our customer ask me if it possible to control mcu gpio, with a beacon service running. For what I know beacon standard is only a lighthouse to check the proximity (streaming simple packet uuid, signal strength etc etc), and the only way to do something like this is to expose a new service running concurrently with beacon ( in practice send multi type of packets). I don't want pairing (beacon<->device app) and don't worry about race condition, if multi devices set/reset a gpio, it's not my business.
I found something similar https://community.estimote.com/hc/en-us/articles/217429867-What-is-GPIO-How-to-set-it-up-, what you think about?
There are libraries or eddystone's extensions to do that? Some project on github?
We prefer to work with Nordic ble module, but if you know solution based on other mcu, you are welcome.
Thanks for your help
Standard beacons (iBeacon, Eddystone, AltBeacon) are transmit only devices. They simply send out advertisements at a fixed rate with a unique identifier. Some manufacturers expose proprietary configuration interfaces as read-write Bluetooth LE GATT Services. But there is no standard GATT Service that does this, and the manufacturer-specific schemes are designed specifically to set beacon identifiers and other operating parameters.
I don't think there are beacon-specific libraries or extensions that will help with this, beyond standard Bluetooth LE SDKs for iOS and Android. In order to accomplish this goal with a Nordic BLE module you would need to build your own custom system:
Write custom Nordic firmware (that sits alongside beacon transmission firmware) that exposes a new Bluetooth LE GATT Service. The service would expose a writable GATT Attribute that would control the GPIO pin.
Write custom mobile app code that connects to this GATT Service (CoreBluetooth on iOS and android.bluetooth on Android), and writes to the GATT attribute to control the pin.
One thing you must be careful of is that connecting to to a GATT Service will typically stop a Bluetooth Peripheral from advertising (meaning it won't transmit as a beacon). So you may wish to drop the connection quickly to prevent mobile devices or other Bluetooth Centrals from stoping the beacon transmissions.
I am working on using the Bluetooth low energy modem with Linux. I am using the command line option for that i.e. hcitool . I am able to the find the devices using the command: $ hcitool scan
It is working fine for me, also I am able to broadcast my device using :
sudo hciconfig hci0 leadv
It is also working fine. But I want to add the services and characteristic to the modem device which can be detected by other device. I have tried sdptool add but it is not working for me. Does anyone know how to add the services and characteristics to the peripheral using the command line tools in ubuntu?
Edit: My modem is broadcasting but not able to explore the services and characteristic to the other BLE device. Now I am able to set the name of device using hcio name command
Edit: Now I am able to render the services and characteristic, by simultaneously running sudo hcidump command. But I am not able to track from where I am getting those services and characteristics. One definite observation is those services are rendering from the machine.
SDP is absent in BLE. Broadcast/advertise frame and GATT client/server are used instead.
Several links:
BlueZ gatttool: command line tool to run common GATT procedures
BlueZ GATT's ready profiles
hint: DBUS
GATT and DBUS example
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
http://comments.gmane.org/gmane.linux.bluez.kernel/29547
I used to broadcast BT services by following this article. This page not only shouws you how to advertise a profile, but also gives you an example on how to implement the HSP profile.
To know the bt class you need to announce, you can check this other page.
What are the IPC mechanisms used in webos for bluez connection, also to develop any bluetooth profile in webos, are the proper methods exposed or bluetooth , can someone explain me on the luna bus interaction with bluez ?
Luna-bus system is used in webos for bluez connection.
"com.palm.bt" is a Luna service name for webos bluetooth. Methods such as connect, write, read and close should be defined in bluetooth adapter and you can use this method using luna-send command. You can find the luna-send command example here: http://www.openwebosproject.org/docs/developer_guide/tools/luna_send/#.Uliv2mQqd1M
I have been asked to figure out how to achieve bluetooth communication through an off-the-shelf dongle (in this case a dongle utilizing the Broadcom BCM2045 chip) using the FTDI Vinculum 2 (VNC2) USB controller. I have custom firmware written for the VNC2 to communicate with a generic USB device with the VNC2 acting as the host, and I can successfully read the VID and PID from the dongle as well as the USB device class, subclass, and protocol. I can also send data to the dongle using the bulk data endpoint and I believe the device is receiving though I have no way to tell at the moment.
So I believe I can communicate with the dongle, the problem is I have no idea WHAT to communicate to it in order to set it up in discoverable mode or to pair it with another discoverable device, nor how to actually transmit data through the wireless link once it is paired. I don't even know if there exists a standard communication protocol for this type of thing or if every device will be different. I have a vague understanding of the bluetooth protocol stack and it is my understanding that I won't be required to fully understand that as it should be implemented in the dongle on one end and in the android smartphone that we hope to connect to on the other end. Like I said, I can currently send data to the bulk endpoint, is it true that this endpoint is only for data transfer over the wireless link and I will need to connect to a different endpoint in order to send setup/configuration messages to the dongle?
In short, I need to know what data to send over the USB bus to control any generic bluetooth dongle if possible or at least one specific bluetooth dongle. I have a USB port sniffer but the complexity of the output while using the dongle to communicate is staggering and I doubt I'll ever figure it out.
Thank you in advance.
Bluetooth dongles communicate with host software stack using HCI (host control interface), which is defined in the Bluetooth spec. For reference, you can look at source code for the open source BlueZ stack (standard linux stack). You could run BlueZ on linux talking to your USB dongle, and use hcidump to capture actual packets going across HCI. You can also check out hcitool and hciconfig for performing specific actions.