Supposing i have a sine wave and would like to locate a point of value 1.5 or the first value after 1.5 only on the rising edge, how would i go about getting this done. The location of the point should be determined at all rising edges of the sine wave.
Thank you.
"Locating a point" doesn't mean much to me.
If you want to trigger some action when the sine wave reaches the value of 1.5 volts, that can be done using the Arduino built in analog comparator. It compares the input voltage to a reference voltage that you define, and provides a signal for input less than or greater than the reference.
Alternatively you can measure the input voltage with the analogRead function, but you are limited to relatively low frequencies for the input sine wave.
Looking at it should make it pretty easy to spot.
If you know the function, plug in 1.5 and find the Y.
Then +/- the period and you'll have half of the rest of the Y values only along one edge.
If you are not really in needs for extreme precision (i.e. the period of your sine is long / frequency low)you can just take a measure in the loop and keep the previous one in memory. You know you are at your point if the current value is >= 1.5 and current value is higher than the previous one (meaning you are on the rising edge)