Added arduino libs

libraries/PID/examples/PID_AdaptiveTunings/PID_AdaptiveTunings.ino

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+/********************************************************
+ * PID Adaptive Tuning Example
+ * One of the benefits of the PID library is that you can
+ * change the tuning parameters at any time.  this can be
+ * helpful if we want the controller to be agressive at some
+ * times, and conservative at others.   in the example below
+ * we set the controller to use Conservative Tuning Parameters
+ * when we're near setpoint and more agressive Tuning
+ * Parameters when we're farther away.
+ ********************************************************/
+
+#include <PID_v1.h>
+
+#define PIN_INPUT 0
+#define PIN_OUTPUT 3
+
+//Define Variables we'll be connecting to
+double Setpoint, Input, Output;
+
+//Define the aggressive and conservative Tuning Parameters
+double aggKp=4, aggKi=0.2, aggKd=1;
+double consKp=1, consKi=0.05, consKd=0.25;
+
+//Specify the links and initial tuning parameters
+PID myPID(&Input, &Output, &Setpoint, consKp, consKi, consKd, DIRECT);
+
+void setup()
+{
+  //initialize the variables we're linked to
+  Input = analogRead(PIN_INPUT);
+  Setpoint = 100;
+
+  //turn the PID on
+  myPID.SetMode(AUTOMATIC);
+}
+
+void loop()
+{
+  Input = analogRead(PIN_INPUT);
+
+  double gap = abs(Setpoint-Input); //distance away from setpoint
+  if (gap < 10)
+  {  //we're close to setpoint, use conservative tuning parameters
+    myPID.SetTunings(consKp, consKi, consKd);
+  }
+  else
+  {
+     //we're far from setpoint, use aggressive tuning parameters
+     myPID.SetTunings(aggKp, aggKi, aggKd);
+  }
+
+  myPID.Compute();
+  analogWrite(PIN_OUTPUT, Output);
+}
+
+