I am able to use bleak and get data from all 5 BLE sensors. But the problem is that I am unable to identify which data is from which device. I mean i need a string representing the address of the device alongwith the data itself.
I was able to get data simultaneously from all the BLE modules using bleak in Windows, as well as on raspberry pi.
The only problem with Windows is that if you use Bluetooth 4.2 adapter & above. It will be much better for the high speed data rate, and proper devices connection handling. As with the 4.0 adapter, I have always gone through one or two exceptions each time i started the script, and the maximum number of connections I got was 3.
When i tried this script on Raspberry pi 3b+, it has on-board chip of Bluetooth 4.2. It was able to give high speed data rate, and my 5 sensors were connected to it simultaneously.
Also, The two_devices examples in bleak source code on Github, is very good example for starting with further coding.
And if you run the script and found the data on console, but you were unable to get that which data is from device. Then you need to use functools, (what it does is it will inject the client you're connected to at present, with the callback function, and it will make the work much easier).
Check this out on Github: https://github.com/hbldh/bleak/issues/601
Related
I'm currently working on a research project which revolves around me getting to know the transfer speeds of BLE in a simple setting. To be specific, I'll be working with an Arduino Nano 33 BLE board. I'm well aware that BLE v5 is capable of reaching speeds of up to 1Mb/s (Mega-bits/s) but is unrealistic in real-world applications. Are there any resources that I can get the transfer speeds of BLE? If not, I'm guessing I will have to work with an experimental setup for finding the speeds for my specific use-case. Thank you in advance!
The Bluetooth Radio on the Arduino Nano 33 BLE is built into the NRF52840 MCU.
More information on the Radio is found here:
https://infocenter.nordicsemi.com/topic/ps_nrf52840/radio.html?cp=4_0_0_5_19
There are definitely ways to determine real throughput of this peripheral, you just need a packet sniffer (link below) or have a transmitter/receiver board-to-board setup.
Packet Sniffer:
https://www.nordicsemi.com/Products/Development-tools/nRF-Sniffer-for-Bluetooth-LE
The board-to-board setup will have the relay serially send the number of packets received to a PC for analysis. You could configure the relay board to send the number of packets received within a certain interval (using the Timers in the NRF52840 with <microsecond precision).
If your project changes and you no longer need to use BLE and you would like to increase throughput to ~1.5Mbps, I developed and tested a working configuration of the NRF52840's Radio on the Arduino Nano 33 BLE. Link below.
https://forum.arduino.cc/t/stream-binary-data-from-arduino-nano-33-ble-to-pc-via-ble/917206
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'm trying to build a small program that reads the BLE beacons around my devices and parses the ones that I'm interested in to publish on MQTT. I'm using Raspberry Pis to run the code, I develop using my mac. The language is JS (Node 10.x), my Pis are running latest Buster, that is Bluez 5.50 and a fork of Noble to interface with the bluetooth layer.
For some reason, on one of the Pis that I moved to an open area (in order to get clear readings), I only receive the Scan Response Packets. I never receive the Advertisement Packet. I do sometimes receive the Advertisement packet for one of the device that is quite far away, making me suspect that signal comes in play here. From the Pis in the network cabinet (small Faraday cage) I do get inconsistently both packets every now and then (reason for dedicating a Pi in an open location).
Is there any way to force Bluez to always receive the Advertisement packet? Is there a bug somehow or a feature that I am not using properly?
EDIT
I installed tshark to monitor closely, and I do see the advertisement packet reaching my device. This means that BlueZ is ignoring them. Is there some complete documentation on how to use bluetoothctl and how to configure the bluetooth deamon/tool in order for these packets to be read?
After many days investigating, I manage to get the desired result for my project. I first thought of using the bluewalker project to access the raw packets. With this you can scan in passive mode, meaning only the advertising packet is retrieved.
By looking more in depth into noble project, the one I actually use to interface with, there is a workaround to scan in passive mode (https://github.com/noble/noble/issues/701), but also a variable to capture both advertising and response packets: NOBLE_REPORT_ALL_HCI_EVENTS. Setting this to 1 will give me exactly what I need, both the scan request which contains the data that changes more frequently, and the scan response that contains more data, such as min/max 24h values. And as a matter of fact, combining this setting with duplicates=false seems to give me only the scan request data, just like in passive mode.
Question still opened:
Having this, I still don't know how to use bluetoothctl to display both scan request data along with the scan response. Nor did I find a way to force the scan mode to passive. I could investigate more hcitool hciconfig, but they are deprecated (although every article on the internet refers to them).
My current is on Flutter using Dart and working with Bluetooth low energy devices. I have the basics up using this library and am able to do the following
1. Search for devices and list
2. Connect to device
3. Retrieve services and read characteristic values
4. Subscribe to changes on characteristics.
In order to interact with device correctly I need to read and write from the correct services/characteristics to read data and set things like resistance on the flywheel
I have used the below link and have started mapping out the services, however although the reading can be worked out. The writing to characteristics is a bit out of my reach.
https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.service.cycling_power.xml
The question is.
Does any have experience working BLE cycle trainers and could provide
some insight into how to read and manage services and characteristics
appropriately?
I asked this same question a few months ago, but I've run into another roadblock and I'm hoping someone will have a flash of insight. The is the previous thread: Detecting if the monitor is powered off
I'm trying to figure out the power status of a monitor, in particular a TV that is plugged in via HDMI. I'm running Ubuntu 10.10 with nVidia ION video cards. These PCs will be running some digital signage and I need to make sure the power is on to the TV during business hours. I have a working Python script controlling an IR transmitter to turn the TV off and on. The last piece of the puzzle is to know the current state of the TV.
In my previous thread, I found I could use ddccontrol to get information from the monitor. That worked great for a traditional Asus monitor plugged in via HDMI. However, the Vizio TV says it doesn't support DDC.
I've also tried using get-edid to get live resolution and color information, but that fails to return any information from the TV.
I've tried udevadm monitor but an event only fires on the initial monitor plugin.
I have a feeling that the nVidia drivers are blocking these calls to the monitor, but I can't confirm that.
Ultimately, all I'm looking for is a single byte of information that changes when the monitor turns off.
EDIT: So, I'm coming to the conclusion that this may not be possible. At least not consistently possible across various combinations of video cards and monitors/TVs. The next idea I have is to monitor power usage on an outlet. I first looked at Kill A Watts, but they are completely stand alone. After several hours of searching, I came across Digi and their XBee radios. I ordered one of XBee's Smart Plugs from Digi and a XBee radio and USB adapter from Spark Fun. My current plan is to use a Python script that polls the Smart Plug for power usage.
The plug and radio were kind of expensive. Does anybody know of a power meter that plugs in? Everything I found was wireless. I'd like to be able to connect to it via USB, ethernet, or serial.
EDIT 2:
I could never get the XBee plug to work. It's incredibly difficult to configure the plug unless you buy one of Digi's gateways.
I ended up building my own current sensor. It's Arduino based and cost about $60 in parts. I wrote about it here: http://trafficlightads.net/2011/09/06/an-arduino-current-sensor/
I have a couple of Watts up? .Net models that have USB and Ethernet for monitoring devices and controlling devices. The .Net model adds Ethernet and an internal relay to turn the attached device on and off. This could be used to eliminate the possibility of IR being blocked and not being able to transition the state of the TV.
Watts up? .Net Product Link
They aren't cheap, but they are well-built. I recommend getting the international model if you want the most flexibility in outlet type. This allows you to use your own in and out cords. In the USA model the input cord is hard-wired/integrated.
Good luck.