USBvalve is a tool developed by a GitHub user known as cecio.
It allows the detection of what a USB device is trying to do when plugging it into a device.
Some USB devices, commonly known as BadUSB might be trying to execute commands on the target device.
The below video is an example of what a BadUSB device can do. It is being detected by the USBvalve and then outputted to the computers terminal via serial.