diff --git a/libraries/PulsePattern/PulsePattern.cpp b/libraries/PulsePattern/PulsePattern.cpp
index 9e04731f..8fa6e601 100644
--- a/libraries/PulsePattern/PulsePattern.cpp
+++ b/libraries/PulsePattern/PulsePattern.cpp
@@ -2,21 +2,26 @@
 //    FILE: PulsePattern.cpp
 //  AUTHOR: Rob dot Tillaart at gmail dot com  
 // VERSION: see PULSEPATTERN_LIB_VERSION in .h
-// PURPOSE: PulsePatternOut library for Arduino
+// PURPOSE: PulsePattern library for Arduino
 //
 // HISTORY:
 // 0.0.1 - 2012-11-23 initial version
 // 0.0.2 - 2012-11-23 adapted a static PPO
 // 0.0.3 - 2012-12-27 renamed to PulsePattern
-// 0.0.4 - 2012-12-27 code stable enough to publish(?)
+// 0.0.4 - 2012-12-27 code stable(?) enough to publish
+// 0.0.5 - 2012-12-27 code cleanup+comment
 //
 // Released to the public domain
 //
-// TODO 
-// - PRE 1.0 backwards compatibility
+// TODO
+// - fast function iso array to return the next period?
+//   more adaptive to e.g. sensor values. (investigate)
+// - test PRE 1.0 backwards compatibility
 // - move code to .h file so compiler can inline?
 // - optimize timer code
 // - adjust timing to more accurate values -> setTimer()
+// - worker should be private - how???
+// - test invalid array periods
 //
 
 #include "PulsePattern.h"
@@ -27,11 +32,12 @@
 #include "WProgram.h"
 #endif
 
-PulsePattern PPO;
+// Predefined generator (singleton)
+PulsePattern PPGenerator;
 
 ISR(TIMER1_COMPA_vect)
 {
-  PPO.worker();
+  PPGenerator.worker();
 }
 
 PulsePattern::PulsePattern()
@@ -47,6 +53,8 @@ void PulsePattern::init(uint8_t pin, uint16_t * ar, uint8_t size,
 	_pin = pin;
 	_ar = ar;
 	_size = size;
+	// TODO: run over the array to test invalid values? 
+	// constrain them 10-4095?
 	_level = constrain(level, LOW, HIGH);
 	_prescaler = constrain(prescaler, PRESCALE_1, PRESCALE_1024);
 	_cnt = 0;
@@ -82,12 +90,10 @@ void PulsePattern::worker()
 	// set next period & flip signal
 	_level = !_level;
 	digitalWrite(_pin, _level);
-	// TODO small adjustment needed for code overhead?; inline iso call?
-	// for now
+	// TODO: adjustment needed for code overhead when micros?; 
 	// + 5.2 usec for digitalWrite
 	// + 3 usec for settimer call
-	setTimer(_ar[_cnt]-8);
-	
+	OCR1A = (_ar[_cnt]) * (F_CPU/1000000L);
 	_cnt++;
 	if (_cnt >= _size) _cnt = 0;  // repeat
 }
@@ -104,8 +110,10 @@ void PulsePattern::setTimer(uint16_t cc)
 {
 	TCCR1A = 0;
 	TCCR1B = 0;
-	TCNT1 = 0;      	// reset counter
-    OCR1A = cc*16;			// compare A register value;  
+	TCNT1 = 0;      		// reset counter
+    OCR1A = cc*16;			// compare A register value;
+							// *16 makes max period 4095
+							// min period 12?
 	
 	// 4: CTC mode, top = OCR1A
 	TCCR1A = _BV (COM1A1);  	// clear on compare
@@ -114,5 +122,4 @@ void PulsePattern::setTimer(uint16_t cc)
 	TIMSK1 = _BV (OCIE1A);   // interrupt on Compare A Match   
 }
 
-
 // END OF FILE
\ No newline at end of file
diff --git a/libraries/PulsePattern/PulsePattern.h b/libraries/PulsePattern/PulsePattern.h
index 93d3a22a..83ab53ae 100644
--- a/libraries/PulsePattern/PulsePattern.h
+++ b/libraries/PulsePattern/PulsePattern.h
@@ -1,18 +1,18 @@
-#ifndef Histogram_h
-#define PulsePatternOut_h
+#ifndef PulsePattern_h
+#define PulsePattern_h
 // 
-//    FILE: PulsePatternOut.h
+//    FILE: PulsePattern.h
 //  AUTHOR: Rob dot Tillaart at gmail dot com  
-// PURPOSE: PulsePatternOut library for Arduino
+// PURPOSE: PulsePattern library for Arduino
 //          sends a pulse pattern to a digital pin (continuously)
-// HISTORY: See PulsePatternOut.cpp
+// HISTORY: See PulsePattern.cpp
 //
 // Released to the public domain
 //
 
 #include <inttypes.h>
 
-#define PULSEPATTERN_LIB_VERSION "0.0.4"
+#define PULSEPATTERN_LIB_VERSION "0.0.5"
 
 #define NOTINIT -1
 #define STOPPED 0
@@ -50,7 +50,7 @@ private:
 	volatile uint8_t _cnt;
 };
 
-extern PulsePattern PPO;
+extern PulsePattern PPGenerator;
 
 #endif
 // END OF FILE
\ No newline at end of file
diff --git a/libraries/PulsePattern/examples/SOS_demo2/SOS_demo2.ino b/libraries/PulsePattern/examples/SOS_demo2/SOS_demo2.ino
new file mode 100644
index 00000000..87649762
--- /dev/null
+++ b/libraries/PulsePattern/examples/SOS_demo2/SOS_demo2.ino
@@ -0,0 +1,48 @@
+//
+//    FILE: SOS_demo2.pde
+//  AUTHOR: Rob Tillaart
+//    DATE: 2012-11-23
+//
+// PUPROSE: demo of the PulsePattern Library
+//          uses timer1
+//
+
+#include "PulsePattern.h"
+
+// a pattern consists of durations of LOW and HIGH periods
+// so the first line of the SOSpattern is 
+// 500 units LOW, 500 units HIGH etc
+// for a dutycycle of 50% LOW and HIGH should have equal periods
+// NOTE max period = 4095.
+// min period = about 12 
+uint16_t SOSpattern[] = {  
+  500,500,500,500,500,1500,  // SOS in morse
+  1500,500,1500,500,1500,1500, 
+  500,500,500,500,500,1500 };
+
+uint16_t XYZpattern[] = {  
+  100,100,100,100,100,100,  // SOS in morse
+  500,500,500,500,500,500, 
+  1000,1000,1000,1000,1000,1000 };
+
+uint8_t patternSize = 18;
+uint8_t startLevel = LOW;
+
+void setup()
+{
+  Serial.begin(9600);
+  Serial.println("Start PulsePattern");
+
+  // as the prescaler = 1024 the periods of the pattern are a 
+  // few percent less than a millisecond
+  PPGenerator.init(13, SOSpattern, patternSize, startLevel, PRESCALE_1024);
+  PPGenerator.start();
+}
+
+void loop()
+{
+  // dummy code
+  Serial.println(millis());
+  delay(1000);
+}
+