I currently have six or eight of those wall-wart power supplies for various bits of hardware around my machine. There's probably four different voltages represented, and each one usually has a transformer getting nice and warm and chewing up extra power. And, of course, each one is just slightly bigger than the space allowed for it on a power board...

My solution would be to have one unit that had half a dozen leads that could be independently selected for voltage (3, 4.5, 6, 7.5, 9, 12 and 15 volts) and ring/tip polarity. This would be a switched-mode power supply so the efficiency would be nice and high and it wouldn't use much extra power just to keep itself humming. And if it was really good it'd have a separate power converter to present a range of DC voltages and then a bunch of daisy-chainable 'splitter' boxes that would provide the individual leads; so that if I got another device that needed a power supply I could just add an extra splitter box if I'd run out of cables on the first one.

Now, firstly, does anyone know of anything vaguely approximating this device? Does it work with 240V (as well as 120V)? Has anyone had any experience using it?

Seeing nothing like it that I can find in my local electronics stores, I think my next best option is to make my own. I would be building a switched-mode power supply with full circuit isolation, 120/240V switchable IEC input, and plenty of spare grunt for running empegs or (even) charging laptops. It'd be designed to take a lot of beating. It may take me a while to build, though, because I'm not a power supply whiz or even set up with my own electronics workshop. I do have the resources of hardware specialists at work though...

So the other two questions are: firstly, does anyone have any experience building switched-mode power supplies that they'd like to share with me? Secondly, for the rest of you out there plagued by wall-warts, is anyone interested in buying them if I can make them reliably?

And are there any extra features you would want in such a power supply?

Lots of questions here - now it's your turn to answer some of them!

Have fun,

Paul