Converting to a physical quantity

It is not sufficient for a sensor to have a numerical raw value of the measured quantity. It only tells us something if we know something more about the raw value. We must therefore convert it to a known physical unit. We must also provide an estimate of the precision (or error) the value has.

Note

A sensor measuring a physical quantity should report a numerical value, its physical unit, and the corresponding precision, or error of the estimate.

To avoid creating a complex mathematical model that converts our measured light intensity into a known physical unit, which would go beyond the scope of this book, we convert it to a percentage value. Since we've gained a factor of five of precision using our averaging calculation, we can report two decimals of precision, even though the input value is only 1,024 bits, and only contains one decimal of precision:

   double Light = (100.0 * AvgA0) / 1024; 
   MainPage.Instance.LightUpdated(Light, 2, "%"); 
}