Revision 0:ac15e38daeb5, committed 2011-04-20

Comitter:

shimniok

Date:

Wed Apr 20 08:00:25 2011 +0000

Child:

1:70348515ed2f

Commit message:

Initial release

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SimpleFilter.cpp	Wed Apr 20 08:00:25 2011 +0000
@@ -0,0 +1,13 @@
+#include "SimpleFilter.h"
+
+SimpleFilter::SimpleFilter(short shift): _filter_value(0), _shift(shift) {
+    // nothing to do here, really
+}
+
+short SimpleFilter::filter(short value) {
+
+    _filter_value += value - (_filter_value >> _shift);
+    _filter_value >>= _shift;
+    
+    return _filter_value;
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SimpleFilter.h	Wed Apr 20 08:00:25 2011 +0000
@@ -0,0 +1,27 @@
+/** SimpleFilter implements a simple low pass integer "leaky integrator" described here:
+ * 
+ * http://ece124web.groups.et.byu.net/references/readings/Simple%20Software%20Lowpass%20Filter.pdf
+ *
+ * Well suited for filtering ADC integer values very quickly
+ *
+ * Michael Shimniok http://bot-thoughts.com/
+ */
+class SimpleFilter {
+public:
+    /** Creates a new filter object
+     *
+     * @param shift: the number of shifts to perform at each filtering input step; lower means higher bandwidth
+     */
+    SimpleFilter(short shift);
+
+    /** Supplies input to the filter and returns filtered output value
+     *
+     * @param value is the input value to the filter, e.g., some measurement
+     * @returns the filtered output value
+     */
+    short filter(short value);
+
+private:
+    long _filter_value;
+    short _shift;
+};
\ No newline at end of file