Power BLough-R – USB 5V Bypass

The Power-BLough-R is 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.

It’s a simple, non-intrusive way of solving a problem that some 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.

This latest version now breaks out the pins from the female USB connector, 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.

A 3D printed case STL file for the Power-BLough-R is also available on Thingiverse!

How does it work?

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.

Printer Compatibility

The Power BLoughR works with most printers, but there are some exceptions. Some printers, such as the Prusa MK3, already separate the printer’s 5v line 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.

FAQ

• Is there a switch? No. The designer wanted to make this as simple as possible. Standard cheap switches can probably handle standard USB current, but they were concerned about people using these with phone chargers.
• How do you pronounce the name? ‘Power Blocker’, as the designer’s second name (Blough) is pronounced ‘lock!.
• Isn’t this just the same as cutting the 5V line of the USB cable? This is exactly like that, but no cables were harmed in this solution!

Package Contents

• 1x Assembled Power-BLough-R

Resources

• Hackaday Page