I got a measuring instrument which can measure light intensity and this instrument can be connected to a PC via USB.
I now want to be able to read the values from the device via a Raspberry.
When the instrument is connected to the Pi, it shows up when entering 'lsusb' to the terminal and it is also listed under '/dev/usb' as hiddev1
But how can i actually grab the data from the device?
When i enter 'sudo cat /dev/usb/hiddev1' nothing happens.
Thanks in advance for your help
Try using HIDAPI, a cross-platform library for accessing Human Interface Devices.
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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 device that is inserted between a client and a printer.
In the normal case this device should just allow the printing to occur as normal, but if a certain event happens it should instead divert the printing to a PDF file on disk.
In essence it should work as a print server that can decide where to send the data to be printed.
The problem is that I want to achieve this using an USB-A to USB-A cable between the client and the device, and the printer via USB to the device.
The device is at the moment a Raspberry Pie running Raspbian.
Printing from the Pie is tested using CUPS, so that works.
Now for the question(s):
How can I allow printing via USB cable from the client? Simply connecting the device and the client does not allow it to be recognised as a printer. CUPS does not seem to support this sharing option.
Can CUPS be configured to support sharing via USB?
Is there any other print software that supports this?
Is there another OS where this could be achieved easier?
Any input is appreciated!
I'm currently working on a device which is able to work as a keyboard and communicate via Serial with a self-written software.
Now I have to install serial drivers (from Arduino) on different computers if I want to communicate with my application which I actually want to avoid.
Is there any other solution to solve this problem? Is it possible that my microcontroller works as a keyboard AND is able to send and receive data as HID device?
Thanks and greetings!
I actually do something similar with a 32u4, but it receives its serial over the built-in UART. I do this because it's linking between two separate systems. If it were only one system I could implement a 2nd interface. (Don't forget, a USB HID device must have an IN endpoint even if you are not using it.) Or you could just throw a $2 USB/TTL converter on and do it the same as I did.
I'm working on a little Arduino project to create a bluetooth N64 joystick for my Ubuntu box.
I managed to find a sketch to output the controllers state via serial and it works great. Also sending the TX and RX to the little CSR bluetooth module I have works fine.
When I pair with the device I have to use "rfcomm bind" to see the device in my dev directory and 'cat'ing the output shows all the data is coming through as well.
My question is this, what are my next steps for getting Linux to recognize this device as a joystick - i.e. /dev/js0. If I know what I need to do to achieve this I can read up on the necessary steps but at the moment I have absolutely no clue where to start - having not done anything like this in the past. Should I be looking into creating a Kernel Module?
Any information or pokes in the right direction at all would be greatly appreciated - even if it's just an observation.
Writing custom kernel code is definitely not the way to go here.
To make your project appear as a joystick device in Linux you'll want to present it using the Bluetooth HID profile. With that in place everything should "just work" on the client side and you'll see an entry in /dev. The HID profile is pretty comprehensive and is used by most Bluetooth interface devices - keyboards, mice, game controllers etc. the Bluetooth part of this is actually mostly just a thin wrapper around the USB HID protocol.
From the sounds of things your device is currently not advertising itself using that profile.
I have two legacy machines connected to a Linux box with USB using the ftdi_sio driver, to /dev/ttyUSB0 and /dev/ttyUSB1. The Linux box is relaying and analyzing the traffic between the machines. When the Linux box boots up, the machines are connected to the files pretty much randomly. The problem is to know which one is which.
I could just ask the devices, of course, but I'd like to avoid the risk of malfunction due to sending wrong data to the wrong device. Is there a way to figure out, for example, the id of the device connected to a tty file?
Check this Using Linux USB page.
/proc/bus/usb/devices lists information about the devices currently attached to the USB bus. This is very useful when trying to figure out if the device is correctly enumerated.
Maybe you can use the output from lsusb -v and look at iProduct + iSerial to determine the order the devices are attached.