This is Arduino library for measure sampling. It can be used when you need to process some data from sensors. Now it uses sliding window to calculate [Standard deviation] (https://en.wikipedia.org/wiki/Standard_deviation)

When you need to detect some fluctuation in the sensor data flow and you don't have the exact value you may compare with on each measurement.

#include <Sampler.h>

Sampler sampler = Sampler();

void setup() {
    pinMode(0, INPUT);
}

void loop() {
    int sensorValue = analogRead(0);
    sampler.sample(sensorValue);
    int deviation = sampler.deviation();
    if (deviation > 1) {
        //here we go, some fluctuation in data, do something
    }
}

Just copy Sampler folder (with two files inside, Sampler.h and Sampler.cpp) into you Arduino SDK install folder/libraries