This is a basically a pass through device for USB Type A connectors that doesn't connect the 5V line. it has a Male connector and one end and a Female connector at the other.
Well basically it is simple, non-intrusive way of solving a problem that 3D-printers connected to Octoprint machines have, their screen stays on, even when their PSU is off because they are still receiving 5V via USB.
The new version of the PCB now breaks out the pins from the female USB connector (can be seen in the third image above), I've found this useful for adding 5V back into a USB device that is power hungry (such as an external hard drive), especially if using an extension cable.
Plug the Power BLough-R directly into a USB port of the computer running Octoprint and plug the printer's USB cable into the Power BLough-R. Your Octoprint machine will be able to communicate with your printer as normal once your printer's PSU is on.
This has been a little bug bear of mine for a while and wanted to come up with a simple solution for it. Up to this I was plugging out the USB cable every time I turned off my printer.
I also wanted to make a PCB and this is my first ever one, as you might be able to tell. It's certainly not the most complicated device, but it achieves what I set out to do!
There are other solutions to this problem, some people have taken to cutting traces on boards, others have modified the USB cable (either by cutting the 5V line or placing tape over the connector), but I thought this would be a nice, non intrusive way to achieve the goal.
The Power BLoughR works with most printers, but there are some exceptions. Some printers, such as the Prusa MK3, already separate the printers 5v from the USB 5v. When you use the Power BLoughR with these printers, nothing powers the USB to serial chip, so it will not appear in the port drop down in Octoprint. A good general test to know if you need the Power BLoughR or not is, with the printer off, plug in the USB. If the screen turns on, the Power BLoughR should work for you.