diff --git a/CMakeLists.txt b/CMakeLists.txt
index 87f2f45..d8382e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -147,32 +149,32 @@ IF(BUILD_SWIG_BINDINGS)
   ADD_SUBDIRECTORY(lang/swig)
 ENDIF(BUILD_SWIG_BINDINGS)
 
-# pkg-config (use the CPack information)
-# FIND_PACKAGE(PkgConfig)
-# if(PKG_CONFIG_EXECUTABLE)
-#   set(PC_SHORT_NAME "${BUILDSYS_CPACK_NAME}")
-#   set(PC_LONG_NAME "${BUILDSYS_CPACK_NAME}")
-#   set(PC_LIBRARY_NAME "${LIBNIFALCON_CPP}")
-#   set(PC_DESCRIPTION "${CPACK_PACKAGE_DESCRIPTION_SUMMARY}")
-#   set(PC_VERSION "${LIBNIFALCON_MAJOR_VERSION}.${LIBNIFALCON_MINOR_VERSION}.${LIBNIFALCON_BUILD_VERSION}")
-
-#   if(LIBUSB_1_FOUND)
-#     set(PC_REQUIRES "${PC_REQUIRES}libusb-1.0 ")
-#     set(PC_LINK_FLAGS "${PC_LINK_FLAGS}-lnifalcon_comm_libusb ")
-#   endif(LIBUSB_1_FOUND)
-
-#   set(PC_LINK_FLAGS "${lib${PC_LIBRARY_NAME}_LINK_FLAGS} ${PC_LINK_FLAGS}")
-#   set(PC_LINK_FLAGS "-l${PC_LIBRARY_NAME} ${PC_LINK_FLAGS}")
-#   set(PC_COMPILE_FLAGS "${lib${PC_LIBRARY_NAME}_COMPILE_FLAGS}")
-#   set(PC_CONFIGURED_FILE
-#     ${CMAKE_BINARY_DIR}/libnifalcon.pc
-#     )
-#   MESSAGE("-- Generating ${PC_CONFIGURED_FILE}")
-#   configure_file(
-#     ${CMAKE_SOURCE_DIR}/libnifalcon.pc.cmake
-#     ${PC_CONFIGURED_FILE}
-#     @ONLY
-#     )
-#   set(PKG_CONFIG_DIR "${CMAKE_INSTALL_PREFIX}/lib/pkgconfig")
-#   install(FILES ${PC_CONFIGURED_FILE} DESTINATION ${PKG_CONFIG_DIR})
-# endif(PKG_CONFIG_EXECUTABLE)
+#pkg-config (use the CPack information)
+FIND_PACKAGE(PkgConfig)
+if(PKG_CONFIG_EXECUTABLE)
+  set(PC_SHORT_NAME "${BUILDSYS_CPACK_NAME}")
+  set(PC_LONG_NAME "${BUILDSYS_CPACK_NAME}")
+  set(PC_LIBRARY_NAME "${LIBNIFALCON_CPP}")
+  set(PC_DESCRIPTION "${CPACK_PACKAGE_DESCRIPTION_SUMMARY}")
+  set(PC_VERSION "${LIBNIFALCON_MAJOR_VERSION}.${LIBNIFALCON_MINOR_VERSION}.${LIBNIFALCON_BUILD_VERSION}")
+
+  if(LIBUSB_1_FOUND)
+    set(PC_REQUIRES "${PC_REQUIRES}libusb-1.0 ")
+    set(PC_LINK_FLAGS "${PC_LINK_FLAGS}-lnifalcon_comm_libusb ")
+  endif(LIBUSB_1_FOUND)
+
+  set(PC_LINK_FLAGS "${lib${PC_LIBRARY_NAME}_LINK_FLAGS} ${PC_LINK_FLAGS}")
+  set(PC_LINK_FLAGS "-l${PC_LIBRARY_NAME} ${PC_LINK_FLAGS}")
+  set(PC_COMPILE_FLAGS "${lib${PC_LIBRARY_NAME}_COMPILE_FLAGS}")
+  set(PC_CONFIGURED_FILE
+    ${CMAKE_BINARY_DIR}/libnifalcon.pc
+    )
+  MESSAGE("-- Generating ${PC_CONFIGURED_FILE}")
+  configure_file(
+    ${CMAKE_SOURCE_DIR}/libnifalcon.pc.cmake
+    ${PC_CONFIGURED_FILE}
+    @ONLY
+    )
+  set(PKG_CONFIG_DIR "${CMAKE_INSTALL_PREFIX}/lib/pkgconfig")
+  install(FILES ${PC_CONFIGURED_FILE} DESTINATION ${PKG_CONFIG_DIR})
+endif(PKG_CONFIG_EXECUTABLE)
diff --git a/README.txt b/README.txt
index 66ba252..ce864cd 100644
--- a/README.txt
+++ b/README.txt
@@ -110,6 +110,7 @@ Jared Allen
 Alastair Barrow
 Niall Begley
 Edgar Berdahl
+Axel Kohlmeyer
 Steven Martin
 Kevin Ouellet
 Devanshi Shah
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index f3e4626..04eadb6 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -96,6 +96,7 @@ ELSE(NOT Boost_PROGRAM_OPTIONS_FOUND)
     falcon_test_cli/FalconTestBase.cpp 
     falcon_test_cli/FalconLoopTimeTest.cpp 
     falcon_test_cli/FalconCubeTest.cpp 
+    falcon_test_cli/FalconSphereTest.cpp 
     falcon_test_cli/FalconWallTest.cpp 
     falcon_test_cli/FalconColorTest.cpp
     )
diff --git a/examples/falcon_test_cli/FalconSphereTest.cpp b/examples/falcon_test_cli/FalconSphereTest.cpp
new file mode 100644
index 0000000..bb7a9f0
--- /dev/null
+++ b/examples/falcon_test_cli/FalconSphereTest.cpp
@@ -0,0 +1,137 @@
+#include "FalconSphereTest.h"
+
+#include "falcon/core/FalconDevice.h"
+#include "falcon/grip/FalconGripFourButton.h"
+#include "falcon/kinematic/FalconKinematicStamper.h"
+
+FalconSphereTest::FalconSphereTest(boost::shared_ptr<libnifalcon::FalconDevice> d) :
+	FalconTestBase(d),
+	m_radius(0.028),
+	m_stiffness(1000.0),
+	m_isInitializing(true),
+	m_hasPrintedInitMsg(false),
+	m_plusButtonDown(false),
+	m_minusButtonDown(false),
+	m_centerButtonDown(false),
+	m_forwardButtonDown(false)
+{
+	setPrintOnCount(1000);
+	m_falconDevice->setFalconKinematic<libnifalcon::FalconKinematicStamper>();
+	m_falconDevice->setFalconGrip<libnifalcon::FalconGripFourButton>();
+	m_oldpos[0] = m_oldpos[1] = m_oldpos[2] = 0.0;
+}
+
+void FalconSphereTest::runFunction()
+{
+	if(!m_falconDevice->runIOLoop())
+		return;
+
+	boost::array<double, 3> pos = m_falconDevice->getPosition();
+
+	if(m_isInitializing)
+	{
+		if(!m_hasPrintedInitMsg)
+		{
+			std::cout << "Move the end effector all the way out" << std::endl;
+			m_hasPrintedInitMsg = true;
+		}
+		if(pos[2] > .170)
+		{
+			std::cout << "Starting sphere simulation..." << std::endl;
+			m_isInitializing = false;
+			tstart();
+		} else {
+			m_oldpos = pos;
+		}
+		m_lastLoopCount = m_falconDevice->getFalconFirmware()->getLoopCount();
+		return;
+	}
+
+	// increase radius
+	if(m_falconDevice->getFalconGrip()->getDigitalInputs() 
+	   & libnifalcon::FalconGripFourButton::PLUS_BUTTON)
+	{
+		m_plusButtonDown = true;
+	}
+	else if(m_plusButtonDown)
+	{
+		m_plusButtonDown = false;
+		m_radius += 0.002;
+		std::cout << "Plus button pressed... radius now:" << m_radius << std::endl;
+		return;
+	}
+
+	// decrease radius
+	if(m_falconDevice->getFalconGrip()->getDigitalInputs() 
+	   & libnifalcon::FalconGripFourButton::MINUS_BUTTON)
+	{
+		m_minusButtonDown = true;
+	}
+	else if(m_minusButtonDown)
+	{
+		m_minusButtonDown = false;
+		m_radius -= 0.002;
+		std::cout << "Minus button pressed... radius now:" << m_radius << std::endl;
+		return;
+	}
+
+	if(m_falconDevice->getFalconGrip()->getDigitalInputs() 
+	   & libnifalcon::FalconGripFourButton::FORWARD_BUTTON)
+	{
+		m_forwardButtonDown = true;
+	} else{
+		m_forwardButtonDown = false;
+	}
+
+	// make sphere soft radius or "slippery"
+	if(m_falconDevice->getFalconGrip()->getDigitalInputs() 
+	   & libnifalcon::FalconGripFourButton::CENTER_BUTTON)
+	{
+		if(m_forwardButtonDown)
+		{
+			m_stiffness = -300.0;
+                } 
+                else 
+                {
+			m_stiffness = 1000.0;
+                }
+	} else{
+                if(m_forwardButtonDown)
+                {
+			m_stiffness = 500.0;
+		} 
+		else 
+		{
+			m_stiffness = 100.0;
+		}
+	}
+
+
+	boost::array<double, 3> force;
+	force[0] = 0.0;
+	force[1] = 0.0;
+	force[2] = 0.0;
+	
+	// offset z 
+	pos[2] -= 0.11;
+	
+	double dist = sqrt(pos[0]*pos[0]+pos[1]*pos[1]+pos[2]*pos[2]);
+
+	if (dist < m_radius) {
+		if (m_forwardButtonDown) {
+			force[0] = (m_oldpos[0] - pos[0]) * m_stiffness * 10.0;
+			force[1] = (m_oldpos[1] - pos[1]) * m_stiffness * 10.0;
+			force[2] = (m_oldpos[2] - pos[2]) * m_stiffness * 10.0;
+		} else {
+			force[0] = (pos[0] / dist) * (m_radius - dist) * m_stiffness;
+			force[1] = (pos[1] / dist) * (m_radius - dist) * m_stiffness;
+			force[2] = (pos[2] / dist) * (m_radius - dist) * m_stiffness;
+		} 
+	}
+        // dampen position update to remove noise.
+	m_oldpos[0] = 0.4*m_oldpos[0]+ 0.6*pos[0];
+	m_oldpos[1] = 0.4*m_oldpos[1]+ 0.6*pos[1];
+	m_oldpos[2] = 0.4*m_oldpos[2]+ 0.6*pos[2];
+	m_falconDevice->setForce(force);
+}
+
diff --git a/examples/falcon_test_cli/FalconSphereTest.h b/examples/falcon_test_cli/FalconSphereTest.h
new file mode 100644
index 0000000..c06bc11
--- /dev/null
+++ b/examples/falcon_test_cli/FalconSphereTest.h
@@ -0,0 +1,27 @@
+#ifndef FALCON_SPHERE_TEST_H
+#define FALCON_SPHERE_TEST_H
+
+#include "FalconTestBase.h"
+#include "falcon/gmtl/Vec.h"
+
+class FalconSphereTest : public FalconTestBase
+{
+public:
+	FalconSphereTest(boost::shared_ptr<libnifalcon::FalconDevice> d);
+protected:
+	double m_stiffness;
+    double m_radius;
+    boost::array<double, 3> m_oldpos;
+    bool m_plusButtonDown;
+    bool m_minusButtonDown;
+    bool m_centerButtonDown;
+    bool m_forwardButtonDown;
+    
+
+	void runFunction();
+	bool m_isInitializing;
+	bool m_hasPrintedInitMsg;
+
+};
+
+#endif
diff --git a/examples/falcon_test_cli/falcon_test_cli.cpp b/examples/falcon_test_cli/falcon_test_cli.cpp
index e6879e8..ef3f72f 100644
--- a/examples/falcon_test_cli/falcon_test_cli.cpp
+++ b/examples/falcon_test_cli/falcon_test_cli.cpp
@@ -24,6 +24,7 @@
 #include "falcon/util/FalconCLIBase.h"
 #include "FalconLoopTimeTest.h"
 #include "FalconCubeTest.h"
+#include "FalconSphereTest.h"
 #include "FalconWallTest.h"
 #include "FalconColorTest.h"
 
@@ -60,6 +61,7 @@ public:
 			("loop_time_test", "Loops infinitely, printing time every 1000 I/O loops (should be as near 1.0 as possible)")
 #endif
 			("cube_test", "Presents a cube-shaped surface to touch")
+			("sphere_test", "Presents a sphere-shaped surface to touch")
 			("color_test", "Fades LEDs based on the position of the end effector")
 			("x_wall_test", "Presents a wall surface to touch (force along x axis)")
 			("y_wall_test", "Presents a wall surface to touch (force along y axis)")
@@ -84,6 +86,12 @@ public:
 			std::cout << "Running cube test" << std::endl;
 			t.reset(new FalconCubeTest(m_falconDevice));
 		}
+		else if(m_varMap.count("sphere_test"))
+		{
+			while(!calibrateDevice() && !stop);
+			std::cout << "Running sphere test" << std::endl;
+			t.reset(new FalconSphereTest(m_falconDevice));
+		}
 		else if(m_varMap.count("color_test"))
 		{
 			while(!calibrateDevice() && !stop);
diff --git a/include/falcon/core/FalconDevice.h b/include/falcon/core/FalconDevice.h
index 300616d..d4488d9 100644
--- a/include/falcon/core/FalconDevice.h
+++ b/include/falcon/core/FalconDevice.h
@@ -103,7 +103,7 @@ namespace libnifalcon
 		bool setFirmwareFile(const std::string& filename);
 
 		/**
-		 * Conveinence function, calls loadFirmware with a certain number of retries
+		 * Convenience function, calls loadFirmware with a certain number of retries
 		 *
 		 * @param retries Number of times to retry loading firmware before quitting
 		 * @param skip_checksum Whether or not to skip checksum tests when loading firmware (useful with ftd2xx on non-windows platforms)
diff --git a/include/falcon/gmtl/MatrixOps.h b/include/falcon/gmtl/MatrixOps.h
index f0bef0a..943c8aa 100644
--- a/include/falcon/gmtl/MatrixOps.h
+++ b/include/falcon/gmtl/MatrixOps.h
@@ -436,7 +436,7 @@ namespace gmtl
    {
       //gmtlASSERT( ROWS == COLS && "invertFull only works with nxn matrices" );
 
-      const DATA_TYPE pivot_eps(1e-20);         // Epsilon for the pivot value test (delta with test against zero)
+      const DATA_TYPE pivot_eps(1e-10);         // Epsilon for the pivot value test (delta with test against zero)
 
       // Computer inverse of matrix using a Gaussian-Jordan elimination.
       // Uses max pivot at each point
@@ -468,7 +468,7 @@ namespace gmtl
 
          if(gmtl::Math::isEqual(DATA_TYPE(0),pivot_value,pivot_eps))
          {
-            std::cerr << "*** pivot = " << pivot_value << " in mat_inv. ***\n";
+            // std::cerr << "*** pivot = " << pivot_value << " in mat_inv. ***\n";
             result.setError();
             return result;
          }
@@ -551,6 +551,7 @@ namespace gmtl
              n        dimenstion of matrix a.
       */
 
+      const DATA_TYPE pivot_eps(1e-10);         // Epsilon for the pivot value test (delta with test against zero)
       const DATA_TYPE* a = src.getData();
       DATA_TYPE* b = result.mData;
 
@@ -601,9 +602,9 @@ namespace gmtl
          pivot = m[ r[ k] ][ c[ k] ];
 
 
-         if ( gmtl::Math::abs( pivot) <= 1e-20)
+         if ( gmtl::Math::abs( pivot) <= pivot_eps)
          {
-            std::cerr << "*** pivot = " << pivot << " in mat_inv. ***\n";
+            // std::cerr << "*** pivot = " << pivot << " in mat_inv. ***\n";
             result.setError();
             return result;
          }
diff --git a/include/falcon/grip/FalconGripFourButton.h b/include/falcon/grip/FalconGripFourButton.h
index 486a49d..216a5a0 100644
--- a/include/falcon/grip/FalconGripFourButton.h
+++ b/include/falcon/grip/FalconGripFourButton.h
@@ -26,15 +26,21 @@ namespace libnifalcon
 	{
 	public:
 		/**
-		 * Enumeration for the default 4 button grip that comes with the falcon
-		 *
+		 * Enumeration for the default 4 button grip that comes with the falcon.
+		 * This grip has plus and minus buttonsr, one button in the center and 
+		 * one pointing forward. For convenience also symbolic names are provided.
 		 */
 		enum
 		{
 			BUTTON_1 = 0x1,
 			BUTTON_2 = 0x2,
 			BUTTON_3 = 0x4,
-			BUTTON_4 = 0x8
+			BUTTON_4 = 0x8,
+		/* symbolic names */
+			PLUS_BUTTON    = 0x1,
+			FORWARD_BUTTON = 0x2,
+			CENTER_BUTTON  = 0x4,
+			MINUS_BUTTON   = 0x8
 		} FourButtonGripButtons;
 		
 		/**
diff --git a/src/comm/FalconCommLibUSB.cpp b/src/comm/FalconCommLibUSB.cpp
index b38b3a0..1ff056a 100644
--- a/src/comm/FalconCommLibUSB.cpp
+++ b/src/comm/FalconCommLibUSB.cpp
@@ -649,13 +649,11 @@ namespace libnifalcon
 			((FalconCommLibUSB*)transfer->user_data)->setHasBytesAvailable(true);
 			((FalconCommLibUSB*)transfer->user_data)->setReceived();
 		}
-		//We will always at least get modem status bytes back
-		//If we get nothing back, we have disconnected.
-		//Thanks to Devanshi Shah for this fix.
 		else
 		{
-			LOG_ERROR("Device disconnected");
-			((FalconCommLibUSB*)transfer->user_data)->m_isCommOpen = false;
+			// We can't assume 0 bytes back = disconnected on linux, as it causes massive problems
+			// with other applications (mainly Pd). So, just set that we got nothing back and try to figure out
+			// some other way to detect unplugs
 			((FalconCommLibUSB*)transfer->user_data)->setBytesAvailable(0);
 			((FalconCommLibUSB*)transfer->user_data)->setHasBytesAvailable(false);
 			((FalconCommLibUSB*)transfer->user_data)->setReceived();
diff --git a/src/util/FalconCLIBase.cpp b/src/util/FalconCLIBase.cpp
index 6723622..a8d70cc 100644
--- a/src/util/FalconCLIBase.cpp
+++ b/src/util/FalconCLIBase.cpp
@@ -154,8 +154,12 @@ namespace libnifalcon
 		}
 		else
 		{
-			std::cout << "No device index specified to open, cannot continue (--help for options)" << std::endl;
-			return false;
+                        // assume device index 0, if none given
+			if(!m_falconDevice->open(0))
+			{
+				std::cout << "Cannot open falcon device index 0 - Lib Error Code: " << m_falconDevice->getErrorCode() << " Device Error Code: " << m_falconDevice->getFalconComm()->getDeviceErrorCode() << std::endl;
+				return false;
+			}
 		}
 
 		//There's only one kind of firmware right now, so automatically set that.
@@ -256,26 +260,20 @@ namespace libnifalcon
 
 	bool FalconCLIBase::calibrateDevice()
 	{
-		bool homing = false;
 		m_falconDevice->getFalconFirmware()->setHomingMode(true);
 		m_falconDevice->runIOLoop();
 		if(!m_falconDevice->getFalconFirmware()->isHomed())
 		{
-			if(!homing)
+			m_falconDevice->getFalconFirmware()->setLEDStatus(libnifalcon::FalconFirmware::RED_LED);
+			if(m_displayCalibrationMessage)
 			{
-				m_falconDevice->getFalconFirmware()->setLEDStatus(libnifalcon::FalconFirmware::RED_LED);
-				if(m_displayCalibrationMessage)
-				{
-					std::cout << "Falcon not currently calibrated. Move control all the way out then push straight all the way in." << std::endl;
-					m_displayCalibrationMessage = false;
-				}
+				std::cout << "Falcon not currently calibrated. Move control all the way out then push straight all the way in." << std::endl;
+				m_displayCalibrationMessage = false;
 			}
-			homing = true;
 			return false;
 		}
 		std::cout << "Falcon calibrated successfully." << std::endl;
 		m_falconDevice->getFalconFirmware()->setLEDStatus(libnifalcon::FalconFirmware::GREEN_LED);
-		homing = false;
 		return true;
 	}
 }