diff --git a/gr-jay/grc/jay_peak_detect.xml b/gr-jay/grc/jay_peak_detect.xml
index fb605cb..9c53f31 100644
--- a/gr-jay/grc/jay_peak_detect.xml
+++ b/gr-jay/grc/jay_peak_detect.xml
@@ -5,6 +5,12 @@
   <category>[jay]</category>
   <import>import jay</import>
   <make>jay.peak_detect($vlen, $framerate, $bandwidth, $fcenter, $peak_thresh, $peak_hysteresis, $peak_width_min, $peak_width_max, $alpha_s, $alpha_m)</make>
+  <callback>set_bandwidth($bandwidth)</callback>			
+  <callback>set_centerFrequency($fcenter)</callback>			
+  <callback>set_peakThresh($peak_thresh)</callback>			
+  <callback>set_peakHysteresis($peak_hysteresis)</callback>			
+  <callback>set_peakWidthMin($peak_width_min)</callback>			
+  <callback>set_peakWidthMax($peak_width_max)</callback>			
   <!-- Make one 'param' node for every Parameter you want settable from the GUI.
        Sub-nodes:
        * name
diff --git a/gr-jay/include/jay/peak_detect.h b/gr-jay/include/jay/peak_detect.h
index b249956..73d2707 100644
--- a/gr-jay/include/jay/peak_detect.h
+++ b/gr-jay/include/jay/peak_detect.h
@@ -47,6 +47,13 @@ namespace gr {
        * creating new instances.
        */
       static sptr make(int vlen, float framerate, float bandwidth, float fcenter, float peak_thresh, float peak_hysteresis, float peak_width_min, float peak_width_max, float alpha_s, float alpha_m);
+	  	virtual void set_bandwidth(float bandwidth_Hz) = 0;
+		virtual void set_centerFrequency(float freq_Hz) = 0;
+		virtual void set_peakThresh(float thresh_dB) = 0;
+		virtual void set_peakHysteresis(float hysteresis_dB) = 0;
+		virtual void set_peakWidthMin(float width_Hz) = 0;
+		virtual void set_peakWidthMax(float width_Hz) = 0;
+	  
     };
 
   } // namespace jay
diff --git a/gr-jay/lib/peak_detect_impl.cc b/gr-jay/lib/peak_detect_impl.cc
index 27e6029..ab310b3 100644
--- a/gr-jay/lib/peak_detect_impl.cc
+++ b/gr-jay/lib/peak_detect_impl.cc
@@ -48,8 +48,8 @@ namespace gr {
 		, m_fcenter (fcenter)
 		, m_peak_thresh (peak_thresh)
 		, m_peak_hysteresis (peak_hysteresis)
-		, m_peak_width_min ((int)((float)m_vlen/bandwidth*peak_width_min + 0.5f))
-		, m_peak_width_max ((int)((float)m_vlen/bandwidth*peak_width_max + 0.5f))
+		, m_peak_width_min ((int)((float)m_vlen/m_bandwidth*peak_width_min + 0.5f))
+		, m_peak_width_max ((int)((float)m_vlen/m_bandwidth*peak_width_max + 0.5f))
 		, m_alpha_s (alpha_s)
 		, m_alpha_m(alpha_m)
 		, m_frameCount(0)
@@ -96,7 +96,49 @@ namespace gr {
 		delete [] m_pXm;
 		delete [] m_pXs;
 		delete [] m_pX;
-    }
+		}
+
+	void peak_detect_impl::set_bandwidth(float bandwidth_Hz)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		m_bandwidth = bandwidth_Hz;
+		fprintf(stderr, "set_bandwidth(%f)\n", bandwidth_Hz);
+	}
+
+	void peak_detect_impl::set_centerFrequency(float freq_Hz)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		m_fcenter = freq_Hz;
+		fprintf(stderr, "set_centerFrequency(%f)\n", freq_Hz);
+	}
+
+	void peak_detect_impl::set_peakThresh(float thresh_dB)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		m_peak_thresh = thresh_dB;
+		fprintf(stderr, "set_peakThresh(%f)\n", thresh_dB);
+	}
+
+	void peak_detect_impl::set_peakHysteresis(float hysteresis_dB)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		fprintf(stderr, "set_peakHysteresis(%f)\n", hysteresis_dB);
+		m_peak_hysteresis = hysteresis_dB;
+	}
+		
+	void peak_detect_impl::set_peakWidthMin(float width_Hz)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		fprintf(stderr, "set_peakWidthMin(%f)\n", width_Hz);
+		m_peak_width_min = (int)((float)m_vlen/m_bandwidth*width_Hz + 0.5f);
+	}
+
+	void peak_detect_impl::set_peakWidthMax(float width_Hz)
+	{
+		boost::mutex::scoped_lock guard(m_mutex);
+		fprintf(stderr, "set_peakWidthMax(%f)\n", width_Hz);
+		m_peak_width_max = (int)((float)m_vlen/m_bandwidth*width_Hz + 0.5f);
+	}
 
 	float peak_detect_impl::mean(float* pSrc, int length)
 	{
diff --git a/gr-jay/lib/peak_detect_impl.h b/gr-jay/lib/peak_detect_impl.h
index e076bd5..dca2461 100644
--- a/gr-jay/lib/peak_detect_impl.h
+++ b/gr-jay/lib/peak_detect_impl.h
@@ -262,6 +262,8 @@ namespace jay {
 		};
 		
 	private:
+		boost::mutex m_mutex;
+		
 		void check_pair(pmt::pmt_t pair)
 		{
 			pmt::pmt_t key = pmt::car(pair);
@@ -360,6 +362,14 @@ namespace jay {
 		float mean(float *pSrc, int length);
 		std::vector<int> findPeakPos(float* pSrc, int length, float thresh);
 		
+		// Callbacks
+		void set_bandwidth(float bandwidth_Hz) override;
+		void set_centerFrequency(float freq_Hz) override;
+		void set_peakThresh(float thresh_dB) override;
+		void set_peakHysteresis(float hysteresis_dB) override;
+		void set_peakWidthMin(float width_Hz) override;
+		void set_peakWidthMax(float width_Hz) override;
+
 		void sort(std::vector<Peak>&peaks)
 		{
 			int n = peaks.size();