File content as of revision 2:997f57aee3b7:

#ifndef WEIGHTED_AVERAGE_H
#define WEIGHTED_AVERAGE_H

// Updated every 4th sample, ~16ms
#define WEIGHTED_BUFFER_SIZE 64

class WeightedAverage
{
    public: 
        explicit WeightedAverage()
        {
            reset();
        }
        
        void add(float reading)
        {
            total -= buff[ptr % BUFFER_SIZE];
            total += reading;
            buff[ptr++] = reading;
        }
        
        float average()
        {
            float avg = 0;
            
            int n = (BUFFER_SIZE > ptr ? BUFFER_SIZE : ptr);
            
            for(int i = 0; i < n; i++)
            {
                avg += (i * buff[i]);   
            }
            
            return avg / ((n * (n + 1)) / 2);
        }
        
        void reset()
        {
            ptr = 0;
            total = 0;
            for(int i = 0; i < BUFFER_SIZE; i++)
                buff[i] = 0.0f;
        }
        
    private:
        unsigned long ptr;
        float total;
        float buff [WEIGHTED_BUFFER_SIZE];
};

WeightedAverage leftWeightedAvg;
WeightedAverage rightWeightedAvg;
WeightedAverage frontWeightedAvg;

#endif