So I’ve opened up and checked out the power bar I mentioned over the weekend (officially a PowerAuthority Model F5C120 from Belkin). It works fine, and everything on the inside is in top shape. (Score!)

For a little background, I’ve been switching my overhead lights with an outlet strip, with another strip nearby for “the brights”. I have some other power adapters and tools that I manually plug into these strips when needed. No doubt, this could definitely be a useful peripheral as-is, but it looked like it had some highly exploitable free space in it’s case. This led me to investigate (and plan) further.

The inner case has a large middle section that’s empty, save for the wires carrying switched phases heading back to the outlets. This section has over an inch of clearance, so I started thinking about what power supplies I had the parts to build. That’s plenty enough room for some proto board with some regulators on it (reminds me of the phrase, yak shaving).

As an alternative to building a power supply from scratch, I went through my orphaned/extra/funky wall rats box, and I hit gold! I found a 5V/12V switching power supply I had sitting around, probably from an external CD burner that no longer exists. It’s slim and will put out 1.5 Amps to outputs of 5 and 12 volts, so it’s next step in life will be to join this power bar.

Here’s the power bar (you can see the 5/12 volt supply already partially integrated):

If this is to be a bench supply, I’ll need some way of getting the power out. I started planning a set of jacks or panel on the left side, which led to the need for a set of features that I wanted in my supply. I like to “shoot from the hip” sometimes when designing circuits or gadgets, but I want to use this supply for  a long time without much modification. I think setting just a few key features will help get me a reliable tool (and get it out of the “in progress” box sooner). Here’s what I’ve come up with for a set of outputs:

• 12 volts on 2 or 4 jacks, with at least one switched – I don’t use this much, but I’d like to have access to it for robotics or car projects.
• 5 volts on several jacks, with some switched – This is my standard voltage, so I want to power my breadboard, as well as nearby stand-alone projects.
• 5 volts on USB jacks (female A) – I power a lot of projects from USB cables, and I don’t necessarily want those all powered from my computer’s ports.
• 3.3 volts and/or a variable voltage – Sometimes I work on 3.3 volts in low-power systems, but I need it seldom enough that a variable voltage output would be more practical.

It looks like I’ll need the circuitry to provide these power levels, and the panel & jacks to interface it to the world. Using the manufactured power supply and an old powered USB hub already covers most of the features. I have some LM317T variable voltage regulators, so I’ll build the variable output from that. Maybe that’ll satisfy my need to build part of it from scratch? I’ll see how I feel after the panel of jacks is completed and installed in the power bar.

I began this post intending to describe and disassemble the USB hub that I have in mind for inclusion, but I think I’ll build the next post around that. For now, here’s the powered USB ports that’ll be on the side of the unit: