diff --git a/RF24.cpp b/RF24.cpp
index d2073b5..7ad8056 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -26,7 +26,7 @@
 
 /******************************************************************/
 
-void RF24::csn(int mode) const
+void RF24::csn(int mode)
 {
   SPI.setBitOrder(MSBFIRST);
   SPI.setDataMode(SPI_MODE0);
@@ -36,14 +36,14 @@ void RF24::csn(int mode) const
 
 /******************************************************************/
 
-void RF24::ce(int level) const
+void RF24::ce(int level)
 {
   digitalWrite(ce_pin,level);
 }
 
 /******************************************************************/
 
-uint8_t RF24::read_register(uint8_t reg, uint8_t* buf, uint8_t len) const
+uint8_t RF24::read_register(uint8_t reg, uint8_t* buf, uint8_t len)
 {
   uint8_t status;
 
@@ -59,7 +59,7 @@ uint8_t RF24::read_register(uint8_t reg, uint8_t* buf, uint8_t len) const
 
 /******************************************************************/
 
-uint8_t RF24::read_register(uint8_t reg) const
+uint8_t RF24::read_register(uint8_t reg)
 {
   csn(LOW);
   SPI.transfer( R_REGISTER | ( REGISTER_MASK & reg ) );
@@ -71,7 +71,7 @@ uint8_t RF24::read_register(uint8_t reg) const
 
 /******************************************************************/
 
-uint8_t RF24::write_register(uint8_t reg, const uint8_t* buf, uint8_t len) const
+uint8_t RF24::write_register(uint8_t reg, const uint8_t* buf, uint8_t len)
 {
   uint8_t status;
 
@@ -87,7 +87,7 @@ uint8_t RF24::write_register(uint8_t reg, const uint8_t* buf, uint8_t len) const
 
 /******************************************************************/
 
-uint8_t RF24::write_register(uint8_t reg, uint8_t value) const
+uint8_t RF24::write_register(uint8_t reg, uint8_t value)
 {
   uint8_t status;
 
@@ -145,7 +145,7 @@ uint8_t RF24::read_payload(void* buf, uint8_t len)
 
 /******************************************************************/
 
-uint8_t RF24::flush_rx(void) const
+uint8_t RF24::flush_rx(void)
 {
   uint8_t status;
 
@@ -158,7 +158,7 @@ uint8_t RF24::flush_rx(void) const
 
 /******************************************************************/
 
-uint8_t RF24::flush_tx(void) const
+uint8_t RF24::flush_tx(void)
 {
   uint8_t status;
 
@@ -171,7 +171,7 @@ uint8_t RF24::flush_tx(void) const
 
 /******************************************************************/
 
-uint8_t RF24::get_status(void) const
+uint8_t RF24::get_status(void)
 {
   uint8_t status;
 
@@ -184,7 +184,7 @@ uint8_t RF24::get_status(void) const
 
 /******************************************************************/
 
-void RF24::print_status(uint8_t status) const
+void RF24::print_status(uint8_t status)
 {
   printf_P(PSTR("STATUS=%02x: RX_DR=%x TX_DS=%x MAX_RT=%x RX_P_NO=%x TX_FULL=%x\n\r"),
   status,
@@ -198,7 +198,7 @@ void RF24::print_status(uint8_t status) const
 
 /******************************************************************/
 
-void RF24::print_observe_tx(uint8_t value) const
+void RF24::print_observe_tx(uint8_t value)
 {
   printf_P(PSTR("OBSERVE_TX=%02x: POLS_CNT=%x ARC_CNT=%x\n\r"),
   value,
@@ -242,7 +242,7 @@ uint8_t RF24::getPayloadSize(void)
 
 /******************************************************************/
 
-void RF24::printDetails(void) const
+void RF24::printDetails(void)
 {
   uint8_t buffer[5];
   uint8_t status = read_register(RX_ADDR_P0,buffer,5);
@@ -371,7 +371,7 @@ void RF24::begin(void)
 
 /******************************************************************/
 
-void RF24::startListening(void) const
+void RF24::startListening(void)
 {
   write_register(CONFIG, read_register(CONFIG) | _BV(PWR_UP) | _BV(PRIM_RX));
   write_register(STATUS, _BV(RX_DR) | _BV(TX_DS) | _BV(MAX_RT) );
@@ -391,20 +391,27 @@ void RF24::startListening(void) const
 
 /******************************************************************/
 
-void RF24::stopListening(void) const
+void RF24::stopListening(void)
 {
   ce(LOW);
 }
 
 /******************************************************************/
 
-void RF24::powerDown(void) const
+void RF24::powerDown(void)
 {
   write_register(CONFIG,read_register(CONFIG) & ~_BV(PWR_UP));
 }
 
 /******************************************************************/
 
+void RF24::powerUp(void)
+{
+  write_register(CONFIG,read_register(CONFIG) | _BV(PWR_UP));
+}
+
+/******************************************************************/
+
 boolean RF24::write( const void* buf, uint8_t len )
 {
   boolean result = false;
@@ -483,14 +490,14 @@ uint8_t RF24::read_payload_length(void)
 
 /******************************************************************/
 
-boolean RF24::available(void) const
+boolean RF24::available(void)
 {
   return available(NULL);
 }
 
 /******************************************************************/
 
-boolean RF24::available(uint8_t* pipe_num) const
+boolean RF24::available(uint8_t* pipe_num)
 {
   uint8_t status = get_status();
   IF_SERIAL_DEBUG(print_status(status));
@@ -587,7 +594,7 @@ void RF24::openReadingPipe(uint8_t child, uint64_t address)
 
 /******************************************************************/
   
-void RF24::toggle_features(void) const
+void RF24::toggle_features(void)
 {
   csn(LOW);
   SPI.transfer( ACTIVATE );
@@ -597,7 +604,7 @@ void RF24::toggle_features(void) const
 
 /******************************************************************/
 
-void RF24::enableAckPayload(void) const
+void RF24::enableAckPayload(void)
 {
   //
   // enable ack payload and dynamic payload features
@@ -624,7 +631,7 @@ void RF24::enableAckPayload(void) const
 
 /******************************************************************/
 
-void RF24::writeAckPayload(uint8_t pipe, const void* buf, uint8_t len) const
+void RF24::writeAckPayload(uint8_t pipe, const void* buf, uint8_t len)
 {
   const uint8_t* current = (const uint8_t*)buf;
 
@@ -648,13 +655,13 @@ boolean RF24::isAckPayloadAvailable(void)
 
 /******************************************************************/
 
-boolean RF24::isPVariant(void) const {
+boolean RF24::isPVariant(void) {
     return p_variant ;
 }
 
 /******************************************************************/
 
-void RF24::setAutoAck(bool enable) const
+void RF24::setAutoAck(bool enable)
 {
   if ( enable )
     write_register(EN_AA, B111111);
@@ -664,7 +671,7 @@ void RF24::setAutoAck(bool enable) const
 
 /******************************************************************/
 
-void RF24::setAutoAck( uint8_t pipe, bool enable ) const
+void RF24::setAutoAck( uint8_t pipe, bool enable )
 {
     uint8_t en_aa = read_register( EN_AA ) ;
     if( enable ) {
@@ -677,21 +684,21 @@ void RF24::setAutoAck( uint8_t pipe, bool enable ) const
 
 /******************************************************************/
 
-boolean RF24::testCarrier(void) const
+boolean RF24::testCarrier(void)
 {
   return ( read_register(CD) & 1 );
 }
 
 /******************************************************************/
 
-boolean RF24::testRPD(void) const
+boolean RF24::testRPD(void)
 {
   return ( read_register(RPD) & 1 ) ;
 }
 
 /******************************************************************/
 
-void RF24::setPALevel(rf24_pa_dbm_e level) const
+void RF24::setPALevel(rf24_pa_dbm_e level)
 {
   uint8_t setup = read_register(RF_SETUP) ;
   setup &= ~(_BV(RF_PWR_LOW) | _BV(RF_PWR_HIGH)) ;
@@ -724,7 +731,7 @@ void RF24::setPALevel(rf24_pa_dbm_e level) const
 
 /******************************************************************/
 
-rf24_pa_dbm_e RF24::getPALevel(void) const
+rf24_pa_dbm_e RF24::getPALevel(void)
 {
   rf24_pa_dbm_e result = RF24_PA_ERROR ;
   uint8_t power = read_register(RF_SETUP) & (_BV(RF_PWR_LOW) | _BV(RF_PWR_HIGH)) ;
@@ -794,7 +801,7 @@ boolean RF24::setDataRate(rf24_datarate_e speed)
 
 /******************************************************************/
 
-rf24_datarate_e RF24::getDataRate( void ) const {
+rf24_datarate_e RF24::getDataRate( void ) {
   rf24_datarate_e result ;
   uint8_t setup = read_register(RF_SETUP) ;
 
@@ -821,7 +828,7 @@ rf24_datarate_e RF24::getDataRate( void ) const {
 
 /******************************************************************/
 
-void RF24::setCRCLength(rf24_crclength_e length) const
+void RF24::setCRCLength(rf24_crclength_e length)
 {
   uint8_t config = read_register(CONFIG) & ~_BV(CRCO) ;
 
@@ -839,7 +846,7 @@ void RF24::setCRCLength(rf24_crclength_e length) const
 
 /******************************************************************/
 
-void RF24::disableCRC( void ) const
+void RF24::disableCRC( void )
 {
   uint8_t disable = read_register(CONFIG) & ~_BV(EN_CRC) ;
   write_register( CONFIG, disable ) ;
diff --git a/RF24.h b/RF24.h
index e4cf87c..81f10ba 100644
--- a/RF24.h
+++ b/RF24.h
@@ -50,7 +50,7 @@ protected:
      *
      * @param mode HIGH to take this unit off the SPI bus, LOW to put it on
      */
-    void csn(int mode) const ;
+    void csn(int mode) ;
 
     /**
      * Set chip enable
@@ -58,7 +58,7 @@ protected:
      * @param level HIGH to actively begin transmission or LOW to put in standby.  Please see data sheet
      * for a much more detailed description of this pin.
      */
-    void ce(int level) const ;
+    void ce(int level) ;
 
     /**
      * Read a chunk of data in from a register
@@ -68,7 +68,7 @@ protected:
      * @param len How many bytes of data to transfer
      * @return Current value of status register
      */
-    uint8_t read_register(uint8_t reg, uint8_t* buf, uint8_t len) const ;
+    uint8_t read_register(uint8_t reg, uint8_t* buf, uint8_t len) ;
 
     /**
      * Read single byte from a register
@@ -76,7 +76,7 @@ protected:
      * @param reg Which register. Use constants from nRF24L01.h
      * @return Current value of register @p reg
      */
-    uint8_t read_register(uint8_t reg) const ;
+    uint8_t read_register(uint8_t reg) ;
 
     /**
      * Write a chunk of data to a register
@@ -86,7 +86,7 @@ protected:
      * @param len How many bytes of data to transfer
      * @return Current value of status register
      */
-    uint8_t write_register(uint8_t reg, const uint8_t* buf, uint8_t len) const ;
+    uint8_t write_register(uint8_t reg, const uint8_t* buf, uint8_t len) ;
 
     /**
      * Write a single byte to a register
@@ -95,7 +95,7 @@ protected:
      * @param value The new value to write
      * @return Current value of status register
      */
-    uint8_t write_register(uint8_t reg, uint8_t value) const ;
+    uint8_t write_register(uint8_t reg, uint8_t value) ;
 
     /**
      * Write the transmit payload
@@ -134,21 +134,21 @@ protected:
      *
      * @return Current value of status register
      */
-    uint8_t flush_rx(void) const ;
+    uint8_t flush_rx(void) ;
 
     /**
      * Empty the transmit buffer
      *
      * @return Current value of status register
      */
-    uint8_t flush_tx(void) const ;
+    uint8_t flush_tx(void) ;
 
     /**
      * Retrieve the current status of the chip
      *
      * @return Current value of status register
      */
-    uint8_t get_status(void) const ;
+    uint8_t get_status(void) ;
 
     /**
      * Decode and print the given status to stdout
@@ -157,7 +157,7 @@ protected:
      *
      * @warning Does nothing if stdout is not defined.  See fdevopen in stdio.h
      */
-    void print_status(uint8_t status) const ;
+    void print_status(uint8_t status) ;
 
     /**
      * Decode and print the given 'observe_tx' value to stdout
@@ -166,7 +166,7 @@ protected:
      *
      * @warning Does nothing if stdout is not defined.  See fdevopen in stdio.h
      */
-    void print_observe_tx(uint8_t value) const ;
+    void print_observe_tx(uint8_t value) ;
 
     /**
      * Turn on or off the special features of the chip
@@ -174,7 +174,7 @@ protected:
      * The chip has certain 'features' which are only available when the 'features'
      * are enabled.  See the datasheet for details.
      */
-    void toggle_features(void) const ;
+    void toggle_features(void) ;
     /**@}*/
 
 public:
@@ -211,14 +211,14 @@ public:
      * in this mode, without first calling stopListening().  Call
      * isAvailable() to check for incoming traffic, and read() to get it.
      */
-    void startListening(void) const ;
+    void startListening(void) ;
 
     /**
      * Stop listening for incoming messages
      *
      * Do this before calling write().
      */
-    void stopListening(void) const ;
+    void stopListening(void) ;
 
     /**
      * Write to the open writing pipe
@@ -245,7 +245,7 @@ public:
      *
      * @return True if there is a payload available, false if none is
      */
-    boolean available(void) const ;
+    boolean available(void) ;
 
     /**
      * Read the payload
@@ -351,15 +351,22 @@ public:
      *
      * @warning Does nothing if stdout is not defined.  See fdevopen in stdio.h
      */
-    void printDetails(void) const ;
+    void printDetails(void) ;
 
     /**
      * Enter low-power mode
      *
-     * To return to normal power mode, either write() some data or
-     * startListening().
+     * To return to normal power mode, either write() some data,
+     * startListening(), or powerUp().
      */
-    void powerDown(void) const ;
+    void powerDown(void) ;
+
+    /**
+     * Leave low-power mode - making radio more responsive
+     *
+     * To return to low power mode, call powerDown().
+     */
+    void powerUp(void) ;
 
     /**
      * Test whether there are bytes available to be read
@@ -370,7 +377,7 @@ public:
      * @param[out] pipe_num Which pipe has the payload available
      * @return True if there is a payload available, false if none is
      */
-    boolean available(uint8_t* pipe_num) const ;
+    boolean available(uint8_t* pipe_num) ;
 
     /**
      * Enable custom payloads on the acknowledge packets
@@ -380,7 +387,7 @@ public:
      *
      * @see examples/pingpair_pl/pingpair_pl.pde
      */
-    void enableAckPayload(void) const;
+    void enableAckPayload(void) ;
 
     /**
      * Write an ack payload for the specified pipe
@@ -396,7 +403,7 @@ public:
      * @param len Length of the data to send, up to 32 bytes max.  Not affected
      * by the static payload set by setPayloadSize().
      */
-    void writeAckPayload(uint8_t pipe, const void* buf, uint8_t len) const ;
+    void writeAckPayload(uint8_t pipe, const void* buf, uint8_t len) ;
 
     /**
      * Determine if an ack payload was received in the most recent call to
@@ -417,7 +424,7 @@ public:
      * @return Returns true if the hardware is RF24L01P (or compatible) and false
      * if its not.
      */
-    boolean isPVariant(void) const ;
+    boolean isPVariant(void) ;
 
     /**
      * Enable or disable auto-acknowlede packets
@@ -427,7 +434,7 @@ public:
      *
      * @param enable Whether to enable (true) or disable (false) auto-acks
      */
-    void setAutoAck(bool enable) const ;
+    void setAutoAck(bool enable) ;
 
     /**
      * Enable or disable auto-acknowlede packets on a per pipeline basis.
@@ -438,7 +445,7 @@ public:
      * @param which pipeline to modify
      * @param enable Whether to enable (true) or disable (false) auto-acks
      */
-    void setAutoAck( uint8_t pipe, bool enable ) const ;
+    void setAutoAck( uint8_t pipe, bool enable ) ;
 
     /**
      * Test whether there was a carrier on the line for the
@@ -448,7 +455,7 @@ public:
      *
      * @return true if was carrier, false if not
      */
-    boolean testCarrier(void) const ;
+    boolean testCarrier(void) ;
 
     /**
      * Test whether a signal (carrier or otherwise) greater than
@@ -460,7 +467,7 @@ public:
      *
      * @return true if signal => -64dBm, false if not
      */
-    boolean testRPD(void) const ;
+    boolean testRPD(void) ;
 
     /**
      * Set Power Amplifier (PA) level to one of four levels.
@@ -471,7 +478,7 @@ public:
      *
      * @param Desired PA level.
      */
-    void setPALevel( rf24_pa_dbm_e level ) const ;
+    void setPALevel( rf24_pa_dbm_e level ) ;
 
     /**
      * Fetches the current PA level. 
@@ -481,7 +488,7 @@ public:
      * by the enum mnemonics are negative dBm. See setPALevel for
      * return value descriptions.
      */
-    rf24_pa_dbm_e getPALevel( void ) const ;
+    rf24_pa_dbm_e getPALevel( void ) ;
 
     /**
      * Set the transmission data rate
@@ -497,20 +504,20 @@ public:
      * is one of 250kbs, RF24_1MBPS for 1Mbps, or RF24_2MBPS, as defined in the
      * rf24_datarate_e enum.
      */
-    rf24_datarate_e getDataRate( void ) const ;
+    rf24_datarate_e getDataRate( void ) ;
 
     /**
      * Set the CRC length
      *
      * @param length RF24_CRC_8 for 8-bit or RF24_CRC_16 for 16-bit
      */
-    void setCRCLength(rf24_crclength_e length) const ;
+    void setCRCLength(rf24_crclength_e length) ;
 
     /**
      * Disable CRC validation
      *
      */
-    void disableCRC( void ) const ;
+    void disableCRC( void ) ;
 
     /**@}*/
 };