Voltage Logging / Multimeter with Arduino


i am building a rig to power my AV Devices (Camera, Harddisk-Recorder etc.pp.) using a V-Mount Battery and a Voltage Converter like this: http://www.lanparte.com/html/129.html

Basically the converter transforms the 14.4v V-Mount Battery output to all sorts of voltages commonly used in the video world. I have a problem though that i need to analyze, because on one port the voltage seems to be dropping occasionally, causing my camera to reset.

I was looking into multimeters with USB Logging output, but the time-resolution (1 measurement per second) seems not exact enough to find the cause. Then i tried to find "multimeter" shields for the arduino, without success. Seriously, right now i don't want to go into building my own voltage dividers, as - as far as i understand electronics - they should use involve isolated circuits as the V-Mount batteries are quite powerful and i dont want to do anythin wrong, as i am not very experienced with electronics.

I found this, which seems perfect: http://www.phidgets.com/products.php?category=8&product_id=1135_0

but additionally to the 19$ for the sensor, they charge almost 50$ shipping which is out of the question. Can anyone advise a not so pricy, accurate solution for what i want to do: like i said, i would happily buy a shield but i didnt find any. So whats the best way to go for me?

cheers, t.

You can use any resistors voltage divider to measure the port, the input of ADC from the arduino only take very low current. arduino can have about 10,000 measurement per second.

Improving your accuracy with these http://provideyourown.com/2012/secret-arduino-voltmeter-measure-battery-voltage/ http://code.google.com/p/tinkerit/wiki/SecretVoltmeter

Would it be safer / more accurate / versatile / easier to use this chip that i found now?

High-Side Measurement CURRENT SHUNT MONITOR http://www.adafruit.com/datasheets/ina169.pdf

if i understand correctly this thing would allow measureing current and has a voltage divider, true?

EDIT: My Mistake, no Voltage divider, just current