Desktop Power Supply

01/27/2016
Kind of a long story here....

In my basement there's an unfinished half where we keep the furnace, water heater, oil tank and a HUGE amount of "Stuff" my wife likes to call "Junk". This is also the home of my workshop. (think workbench, drill press, saws, shelves filled with nuts, bolts, nails, you get the idea. )

The other half of the basement is somewhat finished as it has carpeted floors real walls, a ceiling, lighting.

At the far end of that finished side is a small room I'm calling my "office"

That's where I have my computers, a desk, a small sofa. (quite nice actually)

I got tired of running back and fourth between the office and the workshop while working on small electronic projects that involved programming and other computer resources that were in the office but sometimes needed soldering, tools or other workbench stuff. So I recently added a small work-table next to the desk for "projects". It currently holds some breadboarded electronic projects and my laptop.

Most times, the "projects" are powered by the USB ports of either the desktop computer or the laptop.
I decided to build a small adjustable power supply for use in this space.
I have a lot of old laptop power supply "bricks" that supply around 18-19VDC @ about 3-4amps
I thought one of these would be the perfect input source for my variable supply.
Then I realized that I had one of these always plugged in at my workspace already (for my actual laptop)
So I designed a small desktop supply around that as the source.
When I need power for a project I just disconnect the charger from my laptop and plug it into the PS unit.

Here's what it looks like inside:

All of this was cobbled together from some of that "Stuff" I keep stored in the other half of the basement.
The case is from an old "ATI USB TV Wonder" (Google it) the rest is just parts,
Note the clever adaption of the 10K trimpot. Yes I actually soldered a shaft onto the slotted end and added a small knob for the output voltage adjustment.
I added a USB power connector on one end and a PS/2 Mouse/Keyboard connector at the other.
This PS/2 connector is handy because I can simply insert breadboard wires directly into it.
Next I'll make an actual connector from an old keyboard cable to attach to my breadboards.
(another good use for for that "Stuff" I've collected)

Here's a link to the schematic: DesktopPowerSupply.pdf

Here's some more photos: