You almost never hear of a DC Watt Meter – one just does some mental math with Volts and Amps at the back of one’s head. An AC Watt Meter, on the other hand, can by pretty useful on any workbench.

Unlike the Kill-a-Watt which spits out analog values, the Chinese meter sent digital information out on a ribbon cable with the bus lines labeled. Since the meter was so hackable, [Kalle] took it ...