3D Printer Switcher

When the number of printers increases, I want the changeover switch.

However, a commercially available USB switcher is useless. For a single printer, only configurations with multiple CPUs are considered.

So combine the parts here. This completes the switcher dedicated to 3D printers.

Switching software is troublesome, but hardware switching is quick.

As a result of trying out variously, this configuration is the cheapest and reproducible.

[ 2020.6.1 ] Unfortunately, with this configuration, all 3D printers do not work. It doesn't work with my favorite Cetus3D. Therefore, now I am making a changeover switch that makes full use of a relay circuit. It was very difficult. However, a value was created to match it. My print job has dramatically eased. The reason why it does not work is as follows. First, you need to completely disconnect the printer and CPU from USB for about 1 second. Then connect to another printer again. This sequence must be realized by a relay circuit. M