This was one of my first electronics projects ever and I had a lot of fun. There is a lot of that I would do differently today and I also want to share here the process and failures, that i experienced on the way.
I had the festool mini systainer lying around for some time and always wanted to turn it into something useful. I thought it would make a really cool housing for my power supply and it did.
In my first approach, I opened up the ATX and removed a lot of elements, which made it a really good fit for the box (unfortunately I caused a short circuit and roasted the ATX). In this version however. I left the ATX intact, also for safety reasons, which unfortunately makes it impossible to completely hide it in the box. It sticks out a little bit in the back now.
Building this, I did a lot of rewiring, soldering, trying out several different connectors and plugs. I learned a ton, however If i could start over i would probably build it around one of these breakout boards.
That would also make it a lot easier to replace it. Power supplies tend to not live forever.
However transforming your old pc power supply unit into a nice new lap power supply is pretty straight forward. I'm not going into details here since this has been documented a million times. But the pin-out already offers a lot of different voltages. Even negativ ones.
The variable output including the power meter I basically copied from this version here.
Instead of using the buck-boost-converter, that I ordered and grilled. I went to a local electronics supplier in Berlin, which are surprisingly rare. They could not offer me an all-in-one solution so I went for one boost converter, that transforms a 12V signal into 32V and a buck converter, that pulls it down again via a coarse 50k and a 2k poti for fine tuning. Another 1k poti allows you to limit the current. These converters are super chunky and probably overkill for that use but I had no other option.
I also installed 4 USB-A Outputs with 5V. That comes in handy for powering microcontrollers or charging your phone. The hub I 3D printed in the awsome xhain hackspace. I didn't have my own printer by then.
All in all, I'm quite happy with how it turned out and since then, I'm using it all the time! Let me know what you think about it. During my building process I browsed through endless other cool examples of such a build. Really good starter Project.