The faithful ATX psu mod needed an upgrade with variable voltages and more then 12V so this happened. I got inspired on the web and came up with the following circuit with the parts I could get. If anyone knows a handy way to do this digitally, keep me recommended!
More --> build log
https://hackaday.io/project/16385-variable-power-supply-arduino-compatiblefor arduino variable power supply with www.inviot.com arduino compatible board