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1  Topics / Home Automation and Networked Objects / Re: resistance for input on arduino on: June 13, 2011, 08:15:40 am
4x 200 Ohm
1x 7 Kohm (9v decrese to 5-- for input to arduino
2  Topics / Home Automation and Networked Objects / resistance for input on arduino on: June 13, 2011, 08:07:33 am
Hi guys,
I have a problem with arduino mega ,
I want to measure the consumption of this circuit and I want to measure the resistance to find the watts
according to the formula W=V^2/R...

For example, when I press a switch not to see consumption 0 watts else if I press all the switches together
to see consumption 100mW..


I reached a point with this example >>>http://arduino.cc/en/Tutorial/AnalogInput<<<< but not potentiometer
I want to have the buttons.

with analogRead() function that read values ​​from 0-1023 expect when I press a button to reduce the values but
because the circuit has little resistance does not decrease much, going from 1023 to 1022 with all switches closed,
so I can not measure watts with the scale

for example, when I press one button to decrease from 1023 to 1000.
when I press two button to decrease from 1000 to 980.
when I press three button to decrease from 980 to 950 etc..
I do not care about the exact I just want to reduce the values when I press buttons

How to fix it;
Is there a function that will help me;
You know another way (again with resistance, not current sensor)
Tell me something!!!

Thanks guys and sorry for my bad english.
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