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Jan Olof

Member Since 06 Oct 2010
Offline Last Active Feb 08 2011 08:30 AM
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#8557 Analog Read

Posted by Jan Olof on 27 January 2011 - 02:50 PM

Well I'm stumped. I don't think the netduino can measure current directly. You might need something like this that outputs varying voltage:

http://www.sparkfun.com/products/8883


Thats overkill! :)
You only need a resistor. Calculated by Ohms law.
You need a voltage drop of 3.3 V at 20 mA, and then you just measure the volage over the resistor with the analog input of the Netduino.

165 Ohm at 20 mA gives a drop of 3,3V (max for the Neduino analog input) (U=R*I)

I would select the one closest below 165 Ohm I can find, with 1% accuracy I would take 162 Ohm.

/Jan Olof


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