Power logger

[Guest]

Hi,
I'm looking for a off the shelf meter to log power consumption for my project. average 1uA with pulses of 2Amp MAX I would like to stick a meter in-line and have a log + total power consumed. Anyone seen such a device?

Thanks

[PCM programmer]

I assume you're trying to figure out the expected battery life
for your project.

We had this same problem, and I just did it with a "life test".
I took a PIC demo board with a 16F877 and connected the
battery voltage on the project board to the AN0 pin on the
demo board. Then, once per hour, the 16F877 would read
the A/D value. The program then sent that value and the
event number (1, 2, 3, ... etc) to a PC through the serial port,
where it was displayed in a terminal program. After a few
days, I copied the data on the terminal screen and saved it
in a file. Then I imported it into Excel and converted the A/D
value to a voltage and displayed the data as a graph of the
battery voltage vs. time.

I think I may also have turned the A/D off, when not taking
a sample, so I could reduce the leakage current of the A/D
input pin to almost zero. That way, the A/D board would
not affect the battery life.

[djpark]

It is hard to imagine exactly what application you are making, but you may find it interesting check out MAX471 or MAX472.

This high side current sensor amplifier can measure the bi-direction current flow of 3V-36V with 500uA output for 1A current, you can feed it to a resistor and measure the voltage across. Particularly MAX471 has internal 35 mili-ohm resistor and can measure upto 3A.

It is hard to find in the shop, but NewArk carries it.

-- dj