Álvaro Prieto's Open Source Universal USB Tester Calls Time on Faulty, Mislabeled Cables

Electrical engineer Álvaro Prieto has called time on faulty or mislabeled USB cables, building a dedicated testing board with a wide array of USB connector types — and releasing it as open hardware to help others sort out their junk drawers too.

"Ever wonder if your USB [Type-]C cable is USB2 or USB3? Do you have some charge-only cables hiding in a box just waiting for the right moment to spoil your project plans?! Fear no more," Prieto writes of the project. "I've made a simple board to test most of the things!"

Prieto's USB cable tester has USB Type-A and Type-C sockets to one side, then USB Type-B, micro-USB, mini-USB, and another USB Type-C socket to the other, and is compatible with both true USB and USB-terminated Thunderbolt cables. The face of the board houses a CR2023 coin cell in the center, making the tester entirely stand-alone, while an array of surface-mount LEDs read out precisely what is connected to where.

"Connect your cable to both sides and the signal LEDs will light up if they are connected," Prieto explains. "Want to test a USB [Type-]A to C cable? How about a USB [Type-]A to micro-B? USB [Type-]C to B? Mini-B? You’ve got it!"

Prieto has released a parts list and KiCad project files for the cable tester on GitHub under the Creative Commons Attribution 4.0 license — though it comes with a warning for those building one: "Do not ever plug this into a device," Prieto says, "[as] the pins on one side are all shorted together and that could break it!"

For those wanting something pre-assembled, the GitHub repository also includes a release with files suitable for assembled PCB manufacturing at JLPCB.