Here’s How You Can Make Your Own KVM Switch to Control Multiple Computers

For power users with multiple computers, KVM switches are incredibly useful devices. They allow you to control multiple computers by quickly switching which computer is connected to your keyboard, video montior, and mouse. Despite their popularity and relative simplicity, however, KVM switches are fairly expensive — easily hundreds of dollars for a model designed for several computers.

Luckily, you can build you own for far less money, and More Than User has a great guide on how to do that. The parts list for the build is fairly substantial and will require a custom PCB, but none of the individual components are particularly expensive. Of course, KVM switches are expensive for a reason, and actually getting it all to work isn’t exactly a plug-and-play process.

The More Than User setup relies on the fact that VGA connections carry an I2C signal for controlling inputs, which is actually the original use for the I2C protocol. The keyboard and mouse need to be connected with a USB hub (sorry to those of you still using PS/2 keyboards). But, while building this DIY KVM switch is a big undertaking, the writeup thoroughly explains both how things work and why. Additional features, like a clipboard shared between computers, are planned for the future, but it’s already functional how it is.