map analogRead to voltage value

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if there way/method/formula convert analogread value voltage value?

think use 'map' function conversion.
so guess i'm wondering if analog digital converter accurate enough this? i'm assuming value of 1023 5v? 511 2.5v? ect...

i want know input voltage value of piezo element when 'tap' or 'knock' on it.

thanks


yes map function say. if mapped 0-1023 counts 0-5 each count represent 4.9 millivolts.

there couple of methods better (higher) resolution if attempting measure low in voltage obtain decent readings. first wire stable lower voltage analog reference pin on avr chip , set software activate external reference voltage. other method utilize op amps amplify lower voltage ranges 5vdc maximum input voltage.

measuring pizo's output voltage may challenge generates small ac voltage , without rectification , amplification not useful measurement.

lefty


Arduino Forum > Forum 2005-2010 (read only) > Software > Syntax & Programs > map analogRead to voltage value


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