my project

[nick smith]

hey all

does anyone know how sensitive the analog inputs are on the arduino? i am only getting about a 0.2 volt difference (according to the simple volt meter program john gave us) and i was wondering if that might not be a large enough difference

[John Harrison]

5V returns 1023
0V returns 0

so I guess it has a 5/1023 volt sensitivity in theory, and probably
something more like .1V sensitivity in actual use.

If the change is too small, you can run a simple non-inverting op amp
circuit to magnify. THIS circuit is pretty simple and straightforward
compared to what you have been doing:
http://en.wikipedia.org/wiki/Operational_amplifier_applications#Non-inverting_amplifier

try like 10K for R2 and 1K for R1. Any op amp such as the 358 I gave you
should work.

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[nick smith]

i'll give that a try tomorrow and let you know how its working. thank you