From 677aaeb463151b0aaefafbd244ff5144d07c16a6 Mon Sep 17 00:00:00 2001
From: rob tillaart <rob.tillaart@gmail.com>
Date: Fri, 6 Mar 2015 14:26:17 +0100
Subject: [PATCH] + version 0.1.04 + smaller footprint

---
 libraries/AnalogPin/AnalogPin.cpp | 17 +++++++++++------
 libraries/AnalogPin/AnalogPin.h   |  6 +++---
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/libraries/AnalogPin/AnalogPin.cpp b/libraries/AnalogPin/AnalogPin.cpp
index 47caee83..861eff77 100644
--- a/libraries/AnalogPin/AnalogPin.cpp
+++ b/libraries/AnalogPin/AnalogPin.cpp
@@ -1,7 +1,7 @@
 //
 //    FILE: AnalogPin.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.02
+// VERSION: 0.1.04
 //    DATE: 2014-10-05
 // PURPOSE: wrapper class for analogRead
 //
@@ -9,22 +9,24 @@
 // 0.1.00 - 2013-09-09 initial version
 // 0.1.01 - 2013-11-09 added some comments
 // 0.1.02 - 2014-10-05 changed signatures datatypes
+// 0.1.03 - 2014-12-07 some refactor
+// 0.1.04 - 2015-03-06 refactor smaller footprint
 //
 // Released to the public domain
 //
 
 #include "AnalogPin.h"
 
-AnalogPin::AnalogPin(uint8_t pin)
+AnalogPin::AnalogPin(const uint8_t pin)
 {
     _pin = pin;
     _prevValue = analogRead(pin);
 }
 
-int AnalogPin::read(uint8_t noise)
+int AnalogPin::read(const uint8_t noise)
 {
     int value = analogRead(_pin);
-    if (noise == 0 || abs(value - _prevValue) > noise)
+    if (noise == 0 || ((value - _prevValue) & 0x7FFF) > noise)
     {
         _prevValue = value;
     }
@@ -33,9 +35,12 @@ int AnalogPin::read(uint8_t noise)
 
 int AnalogPin::readSmoothed(uint8_t alpha)
 {
-    alpha = constrain(alpha, 0, 31);
+    if (alpha > 31) alpha = 31;
     int value = analogRead(_pin);
-    value = (alpha*_prevValue + (32-alpha)*value)/32;
+    if (alpha > 0)
+    {
+        value = value + (alpha * (_prevValue - value)) / 32;
+    }
     _prevValue = value;
     return value;
 }
diff --git a/libraries/AnalogPin/AnalogPin.h b/libraries/AnalogPin/AnalogPin.h
index b31603ec..56fd7718 100644
--- a/libraries/AnalogPin/AnalogPin.h
+++ b/libraries/AnalogPin/AnalogPin.h
@@ -1,7 +1,7 @@
 //
 //    FILE: AnalogPin.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.02
+// VERSION: 0.1.04
 //    DATE: 2014-10-05
 // PURPOSE: wrapper class for analogRead
 //     URL:
@@ -18,12 +18,12 @@
 #include "WProgram.h"
 #endif
 
-#define ANALOGPIN_LIB_VERSION "0.1.02"
+#define ANALOGPIN_LIB_VERSION "0.1.04"
 
 class AnalogPin
 {
 public:
-    AnalogPin(uint8_t);
+    AnalogPin(const uint8_t);
 
     // noise 0..255; in practice 0..4
     int read(uint8_t noise = 0);