switching regulator kit?

Another route is to check out some of the surplus outfits for DC-DC converters and regulator modules. New they're a bit pricey (about $25-35, like from Jameco), so see if you can get some surplus units in the range you want. Look hard enough and you should be able to find some ready-made module in the

I have had OK luck breadboarding National Semi's "Simple Switcher" parts on perfboard and point to point wiring. I always seem to need more inductance than I calculate, but that is probably because of poor current estimates on my part.

As Gordon mentioned, you can often buy little switcher modules surplus. I got a nice one to run a 5V single board computer from Herbach Rademan for about $5 as I remember. It's hit or miss with surplus, but they are pretty common.

Regards, Bob

Later, Jon

-------------------------------------------------------------- Jon Hylands snipped-for-privacy@huv.com

Thanks -- that's neat!

Best,

- Joe

That's what I've been doing when I need a custom circuit board -- one of these days I'm going to have to invest in something better. Either a CNC mill (with which I can simply cut traces out of a copper-clad board) or an etching system or some such. Or, find an online service that's not too expensive for small quantities.

Good point. Still, this seems like something almost all of us will need sooner or later -- maybe we get by with linear regulators (as in Dave Cook's "Intermediate Robot Building" book), but our battery life would almost certainly be improved by a switching one.

Jon pointed out Dimension Engineering, which has some neat drop-in replacement regulators, for $15 plus shipping. That's not too bad, and in a small bot where space or weight matter, it'd be a great solution. I still wonder how much a kit based on something like the "Simple Switcher" and a PCB would cost, though.

Let's see, the regulator chip itself looks to cost about $4 from Jameco (for a 1A version). Then you need capacitors, an inductor, maybe a resistor or two, and a PCB. I'm not sure what inductors cost; the other parts shouldn't add up to a dollar, but the PCB would probably be at least $5 unless we got to high-volume production. So we'd be looking at $10 or so.

Hm. At that price, Dimension Engineering's $15 product is probably a better bargain (taking into account the value of our time!).

Best,

- Joe