If you ask us how to measure the current draw from something, we’ll break a power lead and put a multimeter in series with the power supply. If that’s not handy, we’ve been known to take the fuse out of the power supply and replace it with the meter. Crude, but effective. But if you have about $8,000 sitting around, you could go grab a Keithley 2460 SourceMeter.
What’s a SourceMeter? Well, as far as we can tell it is a power supply with very accurate built-in current monitoring and a microprocessor that can display lots of interesting statistics and graphs. In all fairness, this looks like a souped up model, but they start at about half the price which is still a lot more than most hacker budgets.
You might wonder why we’re talking about an $8,000 instrument. Well, it is nice to see what will be popping up on the surplus market at some point. But more than that, this seems like this would be a highly doable hacker project. There are lots of ways to measure current from a shunt resistor to a hall effect device. We certainly know how to make cool embedded systems with nice touch screens. Or you could just pipe the data back to a PC and crunch it all there using your favorite language.
We couldn’t think of any “smart power supply” projects that would compete with the SourceMeter. We’ve seen monitoring on loads and converters. We also see plenty of projects for monitoring AC. After browsing the videos for these SourceMeters, though, we are wondering why we don’t always put a digital monitoring interface on any bench supply we are building.