Got a new one that'll keep track of how much current a small circuit draws and logs totals. I'd guess you'd call it a 'battery gauge' or 'mileage meter' for a batter pack.
Looking for a better idea...if one exist's...
The idea I've got just to measure circuit draw, not battery pack before the regulator draw, now goes like this:
I get a 5v switch-mode regulator (LM2825 type thing) with an external V sense line, run the regulator output thru a low ohm resistor (.001, .01, .1 ohms, how low is low enough? depends on max current draw I suppose), the regulator's external V sense line goes on the circuit side of the resistor.
Measure the voltage on both sides of the resistor with the ADC with respect to Batt- (with a divider if need be and add that current draw to final result), apply a little Kirchoff's and Ohm's law, do the math, and done...I got current draw. I then integrate time into the equation and get mAh (limited by the resolution of time and the ADC and accuracy of the regulator and resistor).
Am I done?
In fact, it would be kinda nice to throw this in-line with most other projects on the bench just to see what they pull...