Hi,
As one of my first real projects, I would like to build an benchtop power supply based on an ATX power supply. I'm not planning to modify the power supply itself, but I would like to add a circuit to it to allow a couple of things. I'm a programmer so maybe my instinct of going right away for a microcontroller is bad, but since I would like it to have only one output with a voltage selector (I was thinking of adding an LCD screen and using a clickable rotary switch to make it good looking) to cycle between the ATX's -12V, 3.3V, 5V, 12V and maybe add a voltage regulator for other voltages, it seemed easier to control transistors on each rails to control which one is active or not.
While this flow makes sense in my head (4 lines - -12V, 3.3V, 5V and 12V - merging into a single one with transistors acting as "gates" and I guess diodes for safety?), it somehow doesn't sound safe... is it? I haven't seen a similar build on the internet... people tend to expose each rail invidually... but I think it would be a better learning experience for me to make it work with a single output rail.
Any feedback is greatly appreciated before I fry anything 
Thanks!
