diff --git a/HamShield.cpp b/HamShield.cpp
index 430e2f4..afadace 100644
--- a/HamShield.cpp
+++ b/HamShield.cpp
@@ -1129,23 +1129,14 @@ uint32_t HamShield::findWhitespaceChannels(uint32_t buffer[],uint8_t buffsize, u
 }
 
 
-/* 
-BUG: I cannot figure out how to attach these interrupt handlers without the error: 
-
-/Users/casey/Documents/Arduino/libraries/HamShield/HamShield.cpp: In member function 'void HamShield::buttonMode(uint8_t)':
-/Users/casey/Documents/Arduino/libraries/HamShield/HamShield.cpp:1125: error: argument of type 'void (HamShield::)()' does not match 'void (*)()'
-/Users/casey/Documents/Arduino/libraries/HamShield/HamShield.cpp:1126: error: argument of type 'void (HamShield::)()' does not match 'void (*)()'
-*/
-
-
-/*
+/* Setup the auxiliary button input mode and register the ISR */
 void HamShield::buttonMode(uint8_t mode) { 
    pinMode(HAMSHIELD_AUX_BUTTON,INPUT);       // set the pin mode to input
-   digitalWrite(HAMSHIELD_AUX_BUTTON,HIGH);   // turn on internal pull up 
-   if(mode == PTT_MODE) { attachInterrupt(HAMSHIELD_AUX_BUTTON, isr_ptt, CHANGE); } 
-   if(mode == RESET_MODE) { attachInterrupt(HAMSHIELD_AUX_BUTTON, isr_reset, CHANGE); }
+   digitalWrite(HAMSHIELD_AUX_BUTTON,HIGH);   // turn on internal pull up
+   sHamShield = this; 
+   if(mode == PTT_MODE) { attachInterrupt(HAMSHIELD_AUX_BUTTON, HamShield::isr_ptt, CHANGE); } 
+   if(mode == RESET_MODE) { attachInterrupt(HAMSHIELD_AUX_BUTTON, HamShield::isr_reset, CHANGE); }
 }
-*/
 
 /* Interrupt routines */
 
@@ -1162,12 +1153,12 @@ void HamShield::isr_ptt() {
    if((bouncer + 200) > millis()) { 
    if(ptt == false) { 
       ptt = true;
-      HamShield::setModeTransmit();
+      sHamShield->setModeTransmit();
       bouncer = millis();
    }
    if(ptt == true) { 
       ptt = false;
-      HamShield::setModeReceive();
+      sHamShield->setModeReceive();
       bouncer = millis();
    } }
 }
@@ -1359,4 +1350,4 @@ void HamShield::AFSKOut(char buffer[80]) {
   startPlayback(AFSK_space, sizeof(AFSK_space));  delay(8); }
 
 }
-*/
\ No newline at end of file
+*/
diff --git a/HamShield.h b/HamShield.h
index 7f2aa97..45949a1 100644
--- a/HamShield.h
+++ b/HamShield.h
@@ -519,8 +519,8 @@ class HamShield {
         uint32_t scanChannels(uint32_t buffer[],uint8_t buffsize, uint8_t speed, uint16_t threshold);
         uint32_t findWhitespaceChannels(uint32_t buffer[],uint8_t buffsize, uint8_t dwell, uint16_t threshold);
         void buttonMode(uint8_t mode);
-        void isr_ptt();
-        void isr_reset();
+        static void isr_ptt();
+        static void isr_reset();
 	void morseOut(char buffer[HAMSHIELD_MORSE_BUFFER_SIZE]);
 	char morseLookup(char letter);
         bool waitForChannel(long timeout, long breakwindow, int setRSSI);
@@ -541,7 +541,7 @@ class HamShield {
         uint32_t GMRS[];
         uint32_t MURS[];
         uint32_t WX[];
-
+        static HamShield *sHamShield; // HamShield singleton, used for ISRs mostly
          
 //          int8_t A1846S::readWord(uint8_t devAddr, uint8_t regAddr, uint16_t *data, uint16_t timeout);
 //          int8_t A1846S::readBits(uint8_t devAddr, uint8_t regAddr, uint8_t bitStart, uint8_t length, uint16_t *data, uint16_t timeout);