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espurna/filters/BaseFilter.h

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+// -----------------------------------------------------------------------------
+// Base Filter (other filters inherit from this)
+// Copyright (C) 2017-2018 by Xose Pérez <xose dot perez at gmail dot com>
+// -----------------------------------------------------------------------------
+
+#if SENSOR_SUPPORT
+
+#pragma once
+
+class BaseFilter {
+
+    public:
+        virtual void add(double value);
+        virtual unsigned char count();
+        virtual void reset();
+        virtual double result();
+        virtual void resize(unsigned char size);
+        unsigned char size() { return _size; };
+
+    protected:
+        unsigned char _size;
+
+};
+
+#endif // SENSOR_SUPPORT

espurna/filters/MaxFilter.h

@@ -0,0 +1,40 @@
+// -----------------------------------------------------------------------------
+// Max Filter
+// Copyright (C) 2017-2018 by Xose Pérez <xose dot perez at gmail dot com>
+// -----------------------------------------------------------------------------
+
+#if SENSOR_SUPPORT
+
+#pragma once
+
+#include "BaseFilter.h"
+
+class MaxFilter : public BaseFilter {
+
+    public:
+
+        void add(double value) {
+            if (value > _max) _max = value;
+        }
+
+        unsigned char count() {
+            return 1;
+        }
+
+        void reset() {
+            _max = 0;
+        }
+
+        double result() {
+            return _max;
+        }
+
+        void resize(unsigned char size) {}
+
+    protected:
+
+        double _max = 0;
+
+};
+
+#endif // SENSOR_SUPPORT

espurna/filters/MedianFilter.h

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+// -----------------------------------------------------------------------------
+// Median Filter
+// Copyright (C) 2017-2018 by Xose Pérez <xose dot perez at gmail dot com>
+// -----------------------------------------------------------------------------
+
+#if SENSOR_SUPPORT
+
+#pragma once
+
+#include "BaseFilter.h"
+
+class MedianFilter : public BaseFilter {
+
+    public:
+
+        ~MedianFilter() {
+            if (_data) delete _data;
+        }
+
+        void add(double value) {
+            if (_pointer <= _size) {
+                _data[_pointer] = value;
+                _pointer++;
+            }
+        }
+
+        unsigned char count() {
+            return _pointer;
+        }
+
+        void reset() {
+            if (_pointer > 0) {
+                _data[0] = _data[_pointer-1];
+                _pointer = 1;
+            } else {
+                _pointer = 0;
+            }
+        }
+
+        double result() {
+
+            double sum = 0;
+
+            if (_pointer > 2) {
+
+                for (unsigned char i = 1; i <= _pointer - 2; i++) {
+
+                    // For each position,
+                    // we find the median with the previous and next value
+                    // and use that for the sum
+
+                    double previous = _data[i-1];
+                    double current = _data[i];
+                    double next = _data[i+1];
+
+                    if (previous > current) std::swap(previous, current);
+                    if (current > next) std::swap(current, next);
+                    if (previous > current) std::swap(previous, current);
+
+                    sum += current;
+
+                }
+
+                sum /= (_pointer - 2);
+
+            } else if (_pointer > 0) {
+
+                sum = _data[0];
+
+            }
+
+            return sum;
+
+        }
+
+        void resize(unsigned char size) {
+            if (_size == size) return;
+            _size = size;
+            if (_data) delete _data;
+            _data = new double[_size+1];
+            for (unsigned char i=0; i<=_size; i++) _data[i] = 0;
+            _pointer = 0;
+        }
+
+    protected:
+
+        unsigned char _pointer = 0;
+        double * _data = NULL;
+
+};
+
+#endif // SENSOR_SUPPORT

espurna/filters/MovingAverageFilter.h

@@ -0,0 +1,51 @@
+// -----------------------------------------------------------------------------
+// Moving Average Filter
+// Copyright (C) 2017-2018 by Xose Pérez <xose dot perez at gmail dot com>
+// -----------------------------------------------------------------------------
+
+#if SENSOR_SUPPORT
+
+#pragma once
+
+#include <vector>
+#include "BaseFilter.h"
+
+class MovingAverageFilter : public BaseFilter {
+
+    public:
+
+        void add(double value) {
+            _sum = _sum + value - _data[_pointer];
+            _data[_pointer] = value;
+            _pointer = (_pointer + 1) % _size;
+        }
+
+        unsigned char count() {
+            return _pointer;
+        }
+
+        void reset() {}
+
+        double result() {
+            return _sum;
+        }
+
+        void resize(unsigned char size) {
+            if (_size == size) return;
+            _size = size;
+            if (_data) delete _data;
+            _data = new double[_size];
+            for (unsigned char i=0; i<_size; i++) _data[i] = 0;
+            _pointer = 0;
+            _sum = 0;
+        }
+
+    protected:
+
+        unsigned char _pointer = 0;
+        double _sum = 0;
+        double * _data = NULL;
+
+};
+
+#endif // SENSOR_SUPPORT