USBMonitor

USBMonitor is a versatile cross-platform library that simplifies USB device monitoring for Windows, Linux and MacOS systems. It enables developers to effortlessly track device connections, disconnections, and access to all connected device attributes.

With USBMonitor, developers can stay up-to-date with any changes in the connected USB devices, allowing them to trigger specific actions whenever a USB device is connected or disconnected. By ensuring consistent functionality across various operating systems, USBMonitor removes the need to address platform-specific quirks, inconsistencies, or incompatibilities, resulting in a smooth and efficient USB device management experience. The uniformity in functionality significantly enhances code compatibility, minimizing the risk of code issues or unexpected breaks when moving between platforms.

At its core, USBMonitor utilizes pyudev (for Linux environments), WMI (for Windows environments), and the I/O Registry (for MacOs environments). Handling all the low-level intricacies and translating OS-specific information to ensure consistency across all systems.

Installation

To install USBMonitor, simply run:

pip install usb-monitor

Usage

Using USBMonitor is both simple and straight-forward. In most cases, you'll just want to start the monitoring Daemon, defining the on_connect and on_disconnect callback functions to manage events when a USB device connects or disconnects. Here's a basic example:

from usbmonitor import USBMonitor
from usbmonitor.attributes import ID_MODEL, ID_MODEL_ID, ID_VENDOR_ID

device_info_str = lambda device_info: f"{device_info[ID_MODEL]} ({device_info[ID_MODEL_ID]} - {device_info[ID_VENDOR_ID]})"
# Define the `on_connect` and `on_disconnect` callbacks
on_connect = lambda device_id, device_info: print(f"Connected: {device_info_str(device_info=device_info)}")
on_disconnect = lambda device_id, device_info: print(f"Disconnected: {device_info_str(device_info=device_info)}")

# Create the USBMonitor instance
monitor = USBMonitor()

# Start the daemon
monitor.start_monitoring(on_connect=on_connect, on_disconnect=on_disconnect)

# ... Rest of your code ...

# If you don't need it anymore stop the daemon
monitor.stop_monitoring()

Output

Linux	Windows

Sometimes, when initializing your software, you may seek to confirm which USB devices are indeed connected.

from usbmonitor import USBMonitor
from usbmonitor.attributes import ID_MODEL, ID_MODEL_ID, ID_VENDOR_ID

# Create the USBMonitor instance
monitor = USBMonitor()

# Get the current devices
devices_dict = monitor.get_available_devices()

# Print them
for device_id, device_info in devices_dict.items():
    print(f"{device_id} -- {device_info[ID_MODEL]} ({device_info[ID_MODEL_ID]} - {device_info[ID_VENDOR_ID]})")

Output

/dev/bus/usb/001/001 -- xHCI_Host_Controller (0002 - 1d6b)
/dev/bus/usb/001/002 -- USB2.0_Hub (3431 - 2109)
/dev/bus/usb/001/003 -- USB_Optical_Mouse (c077 - 046d)
/dev/bus/usb/001/004 -- USB_Compliant_Keypad (9881 - 05a4)
/dev/bus/usb/002/001 -- xHCI_Host_Controller (0003 - 1d6b)

API Reference

USBMonitor(filter_devices = None)

Initialize the USBMonitor instance. It will allow to inspect and monitor connected devices

• filter_devices: tuple[dict[str, str]] | None. A tuple of dictionaries containing the device attributes to filter. If passed, it will only return and monitor devices that match any of the specified filters. For example, if you want to only retrieve and track devices with 'ID_VENDOR_FROM_DATABASE' = 'Realtek' or the device with 'ID_VENDOR_ID' = '1234' and 'ID_MODEL_ID' = '1A2B' you should instantiate with: USBMonitor(filter_devices=({'ID_VENDOR_FROM_DATABASE': 'Realtek'}, {'ID_VENDOR_ID': '1234', 'ID_MODEL_ID': '1A2B'})). Default value is None.

USBMonitor.start_monitoring(on_connect = None, on_disconnect = None, check_every_seconds = 0.5)

Starts a daemon that continuously monitors the connected USB devices in order to detect new connections or disconnections. When a device is disconnected, the on_disconnect callback function is invoked with the Device ID as the first argument and the dictionary of device information as the second argument. Similarly, when a new device is connected, the on_connect callback function is called with the same arguments. This allows developers to promptly respond to any changes in the connected USB devices and perform necessary actions.

• on_connect: callable | None. The function to call every time a device is added. It is expected to have the following format on_connect(device_id: str, device_info: dict[str, dict[str, str|tuple[str, ...]]])
• on_disconnect: callable | None. The function to call every time a device is removed. It is expected to have the following format on_disconnect(device_id: str, device_info: dict[str, dict[str, str|tuple[str, ...]]])
• check_every_seconds: int | float. Seconds to wait between each check for changes in the USB devices. Default value is 0.5 seconds.

USBMonitor.stop_monitoring(warn_if_was_stopped=True)

Stops the monitoring of USB devices. This function will stop the daemon launched by USBMonitor.start_monitoring

• warn_if_was_stopped: bool. If set to True, this function will issue a warning if the monitoring of USB devices was already stopped (the daemon was not running).

USBMonitor.get_available_devices()

Returns a dictionary of the currently available devices, where the key is the Device ID and the value is a dictionary containing the device's information. All the keys of this dictionary can be found at attributes.DEVICE_ATTRIBUTES. They always correspond with the default Linux device properties (independently of the OS where the library is running).

• Returns: dict[str, dict[str, str|tuple[str, ...]]]: A dictionary containing the currently available devices. All values are strings except for ID_USB_INTERFACES, which is a tuple of string

USBMonitor.changes_from_last_check(update_last_check_devices = True)

Returns a tuple of two dictionaries, one containing the devices that have been removed since the last check, and another one containing the devices that have been added. Both dictionaries will have the Device ID as key and all the device information as value. Remember that all the keys of this dictionary can be found at can be found at attributes.DEVICE_ATTRIBUTES.

• update_last_check_devices: bool. If True it will update the internal USBMonitor.last_check_devices attribute. So the next time you'll call this method, it will check for differences against the devices found in that current call. If False it won't update the USBMonitor.last_check_devices attribute.

• Returns: tuple[dict[str, dict[str, str|tuple[str, ...]]], dict[str, dict[str, str|tuple[str, ...]]]]: A tuple containing two dictionaries. The first dictionary contains the information of the devices that were removed since the last check and the second dictionary contains the information of the new added devices. All values are strings except for ID_USB_INTERFACES, which is a tuple of string.

USBMonitor.check_changes(on_connect = None, on_disconnect = None, update_last_check_devices = True)

Checks for any new connections or disconnections of USB devices since the last check. If a device has been removed, the on_disconnect function will be called with the Device ID as the first argument and the dictionary with the device's information as the second argument. The same will occur with the on_connect function if any new device have been added. Internally this function will just run USBMonitor.changes_from_last_check and will execute the callbacks for each returned device

• on_connect: callable | None. The function to call when a device is added. It is expected to have the following format on_connect(device_id: str, device_info: dict[str, dict[str, str|tuple[str, ...]]])
• on_disconnect: callable | None. The function to call when a device is removed. It is expected to have the following format on_disconnect(device_id: str, device_info: dict[str, dict[str, str|tuple[str, ...]]])
• update_last_check_devices: bool. If True it will update the internal USBMonitor.last_check_devices attribute. So the next time you'll call this method, it will check for differences against the devices found in that current call. If False it won't update the USBMonitor.last_check_devices attribute.

Device Properties

The device_info returned by most functions will contain the following information:

Key	Value Description	Example
'ID_MODEL_ID'	The product ID of the USB device.	'0892'
'ID_MODEL'	The name of the USB device model.	'HD_Pro_Webcam_C920'
'ID_MODEL_FROM_DATABASE'	Device model name, retrieved from the device database.	'OrbiCam'
'ID_VENDOR'	The name of the USB device vendor	'046d'
'ID_VENDOR_ID'	The vendor ID of the USB device.	'046d'
'ID_VENDOR_FROM_DATABASE'	USB device vendor's name, from the device database.	'Logitech, Inc.'
'ID_USB_INTERFACES'	A tuple representing the USB device's interfaces.	('0e0100', '0e0200', '010100', '010200')
'DEVNAME'	The device name or path	'/dev/bus/usb/001/003'
'DEVTYPE'	Should always be 'usb_device'.	'usb_device'

Note that, depending on the device and the OS, some of this information may be incomplete or certain attributes may overlap with others.