diff --git a/RF24.cpp b/RF24.cpp
index db39bea..e0fe3c0 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -331,7 +331,7 @@ void RF24::startListening(void)
   ce(HIGH);
 
   // wait for the radio to come up (130us actually only needed)
-  delay(1);
+  delayMicroseconds(130);
 }
 
 /******************************************************************/
@@ -591,5 +591,22 @@ boolean RF24::isAckPayloadAvailable(void)
   return result;
 }
 
+/******************************************************************/
+
+void RF24::setAutoAck(bool enable)
+{
+  if ( enable )
+    write_register(EN_AA, B111111);
+  else
+    write_register(EN_AA, 0);
+}
+
+/******************************************************************/
+
+boolean RF24::testCarrier(void)
+{
+  return ( read_register(CD) & 1 );
+}
+
 // vim:ai:cin:sts=2 sw=2 ft=cpp
 
diff --git a/RF24.h b/RF24.h
index 2bc97c3..6c8fffd 100644
--- a/RF24.h
+++ b/RF24.h
@@ -399,6 +399,27 @@ public:
    * @return True if an ack payload is available.
    */
   boolean isAckPayloadAvailable(void);
+
+  /**
+   * Enable or disable auto-acknowlede packets
+   *
+   * This is enabled by default, so it's only needed if you want to turn
+   * it off for some reason.
+   *
+   * @param enable Whether to enable (true) or disable (false) auto-acks
+   */
+  void setAutoAck(bool enable);
+
+  /**
+   * Test whether there was a carrier on the line for the
+   * previous listening period.
+   *
+   * Useful to check for interference on the current channel.
+   *
+   * @return true if was carrier, false if not
+   */
+
+  boolean testCarrier(void);
   
   /**@}*/
 };
diff --git a/examples/scanner/makefile b/examples/scanner/makefile
new file mode 100644
index 0000000..15cb43b
--- /dev/null
+++ b/examples/scanner/makefile
@@ -0,0 +1,305 @@
+# Arduino Makefile
+# Arduino adaptation by mellis, eighthave, oli.keller
+# Modified by Kerry Wong to support NetBeans
+# Modified by Rob Gray (Graynomad) for use with Windows and no IDE
+#   This works in my environment and I use it to program two different 
+#   328-based boards and a Mega2560. It's not necessarily robust and 
+#   I may have broken something in the original file that I don't use.
+#
+# This makefile allows you to build sketches from the command line
+# without the Arduino environment.
+#
+# Instructions for using the makefile:
+#
+#  1. Copy this file into the folder with your sketch. The project code file
+#	  should have a .c extension however the file gets copied to a .cpp before
+#     compilation so you still write in C++.
+#
+#  2. Modify the lines between the double ### rows to set the paths 
+#     comm ports etc for your system. EG. c:/progra~1/arduino/arduino-00
+#     for the Arduino IDE, Note the use of short folder name, don't use
+#     "Program files" because spaces will break the build.
+#
+#     Set the line containing "MCU" to match your board's processor.
+#     Typically ATmega328 or ATmega2560.  If you're using a LilyPad Arduino,
+#     change F_CPU to 8000000.
+#
+#  3. At the command line, change to the directory containing your
+#     program's file and the makefile.
+#
+#  4. Type "make" and press enter to compile/verify your program.
+#     The default make target will also perform the uplode using avrdude.
+#
+#     The first time this is done all required libraries will be built
+#     and a core.a file will be created in the output folder.
+#
+#  NOTES:
+#     All output goes into a folder called "output" underneath the working folder.
+#     The default all: target creates symbol (.sym) and expanded assembly 
+#     (.lss) files and uploads the program.
+#
+#
+##########################################################
+##########################################################
+# Select processor here
+MCU 			= atmega328p
+#MCU 			= atmega2560
+
+ifeq ($(MCU),atmega2560)
+UPLOAD_RATE 	= 115200
+AVRDUDE_PROTOCOL = stk500v2
+COM 			= 39
+endif
+
+ifeq ($(MCU),atmega328p)
+UPLOAD_RATE 	= 57600
+AVRDUDE_PROTOCOL = stk500v1
+COM 			= 33
+endif
+
+UNAME := $(shell uname)
+
+ifeq ($(UNAME),Darwin)
+ARDUINO_VERSION	= 21
+ARDUINO_DIR 	= /opt/arduino-00$(ARDUINO_VERSION)
+AVR_TOOLS_PATH 	= $(ARDUINO_DIR)/hardware/tools/avr/bin
+AVRDUDECONFIG_PATH = $(ARDUINO_DIR)/hardware/tools/avr/etc
+PORT                    = /dev/tty.usbserial-A600eHIs
+PORT2                   = /dev/tty.usbserial-A9007LmI
+PORT3                   = /dev/tty.usbserial-A40081RP
+else
+ARDUINO_VERSION	= 22
+ARDUINO_DIR 	= /opt/arduino-00$(ARDUINO_VERSION)
+AVR_TOOLS_PATH 	= /usr/bin
+AVRDUDECONFIG_PATH = $(ARDUINO_DIR)/hardware/tools
+PORT 			= /dev/ttyUSB0
+PORT2 			= /dev/ttyUSB1
+endif
+
+# Temporary testing of github Arduino environment
+OLD_DIR 	= /opt/arduino-00$(ARDUINO_VERSION)
+AVR_TOOLS_PATH 	= $(OLD_DIR)/hardware/tools/avr/bin
+AVRDUDECONFIG_PATH = $(OLD_DIR)/hardware/tools/avr/etc
+ARDUINO_DIR 	= /opt/Arduino
+
+PROJECT_NAME 	= $(notdir $(PWD))
+PROJECT_DIR 	= . 
+ARDUINO_CORE 	= $(ARDUINO_DIR)/hardware/arduino/cores/arduino
+ARDUINO_AVR 	= $(ARDUINO_DIR)/hardware/tools/avr/avr/include/avr
+ARDUINO_LIB 	= $(ARDUINO_DIR)/libraries
+F_CPU 			= 16000000
+
+##########################################################
+##########################################################
+
+# Note that if your program has dependencies other than those
+# already listed below, you will need to add them accordingly.
+C_MODULES =  \
+$(ARDUINO_CORE)/wiring_pulse.c \
+$(ARDUINO_CORE)/wiring_analog.c \
+$(ARDUINO_CORE)/pins_arduino.c \
+$(ARDUINO_CORE)/wiring.c \
+$(ARDUINO_CORE)/wiring_digital.c \
+$(ARDUINO_CORE)/WInterrupts.c \
+$(ARDUINO_CORE)/wiring_shift.c \
+
+CXX_MODULES = \
+$(ARDUINO_CORE)/Tone.cpp \
+$(ARDUINO_CORE)/main.cpp \
+$(ARDUINO_CORE)/WMath.cpp \
+$(ARDUINO_CORE)/Print.cpp \
+$(ARDUINO_CORE)/HardwareSerial.cpp \
+$(ARDUINO_LIB)/SPI/SPI.cpp \
+$(ARDUINO_LIB)/EEPROM/EEPROM.cpp \
+../../RF24.cpp
+
+CXX_APP 	= output/$(PROJECT_NAME).cpp
+MODULES 	= $(C_MODULES) $(CXX_MODULES)
+SRC 		= $(C_MODULES)
+CXXSRC 		= $(CXX_MODULES) $(CXX_APP)
+FORMAT 		= ihex
+
+# Name of this Makefile (used for "make depend").
+MAKEFILE = Makefile
+
+# Debugging format.
+# Native formats for AVR-GCC's -g are stabs [default], or dwarf-2.
+# AVR (extended) COFF requires stabs, plus an avr-objcopy run.
+#DEBUG = stabs
+DEBUG =
+
+OPT = s
+
+# Place -D or -U options here
+CDEFS = -DF_CPU=$(F_CPU)L -DARDUINO=$(ARDUINO_VERSION)
+CXXDEFS = -DF_CPU=$(F_CPU)L -DARDUINO=$(ARDUINO_VERSION)
+
+# Place -I options here
+CINCS =  -I$(ARDUINO_LIB)/EEPROM -I$(ARDUINO_CORE) -I$(ARDUINO_LIB) -I$(PROJECT_DIR) -I$(ARDUINO_AVR) -I$(ARDUINO_LIB)/SPI -I../..
+
+CXXINCS = -I$(ARDUINO_CORE) -I$(ARDUINO_LIB)
+
+# Compiler flag to set the C Standard level.
+# c89   - "ANSI" C
+# gnu89 - c89 plus GCC extensions
+# c99   - ISO C99 standard (not yet fully implemented)
+# gnu99 - c99 plus GCC extensions
+#CSTANDARD = -std=gnu99
+CDEBUG 		= -g$(DEBUG)
+#CWARN 		= -Wall -Wstrict-prototypes
+CWARN 		= -Wall   # show all warnings
+#CWARN 		= -w      # suppress all warnings
+CMAP		= -Wl,-Map,output.map 
+####CTUNING = -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
+CTUNING = -ffunction-sections -fdata-sections
+CXXTUNING = -fno-exceptions -ffunction-sections -fdata-sections
+#CEXTRA = -Wa,-adhlns=$(<:.c=.lst)
+MMCU 		= -mmcu=$(MCU)
+
+CFLAGS = $(CDEBUG) -O$(OPT) $(CMAP) $(CWARN) $(CTUNING) $(MMCU) $(CDEFS) $(CINCS) $(CSTANDARD) $(CEXTRA)
+CXXFLAGS = $(CDEBUG) -O$(OPT) $(CWARN) $(CXXTUNING) $(CDEFS) $(CINCS)
+#ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs
+LDFLAGS = -O$(OPT) -lm -Wl,--gc-sections
+#LDFLAGS = -O$(OPT) -lm -Wl,-Map,output/$(PROJECT_NAME).map 
+
+# Programming support using avrdude. Settings and variables.
+AVRDUDE_PORT = $(PORT)
+AVRDUDE_WRITE_FLASH = -U flash:w:output/$(PROJECT_NAME).hex:i
+
+AVRDUDE_FLAGS = -V -F -D -C $(AVRDUDECONFIG_PATH)/avrdude.conf \
+-p $(MCU) -c $(AVRDUDE_PROTOCOL) -b $(UPLOAD_RATE)
+
+# Program settings
+CC 			= $(AVR_TOOLS_PATH)/avr-gcc
+CXX 		= $(AVR_TOOLS_PATH)/avr-g++
+LD 			= $(AVR_TOOLS_PATH)/avr-gcc
+OBJCOPY 	= $(AVR_TOOLS_PATH)/avr-objcopy
+OBJDUMP 	= $(AVR_TOOLS_PATH)/avr-objdump
+AR 			= $(AVR_TOOLS_PATH)/avr-ar
+SIZE 		= $(AVR_TOOLS_PATH)/avr-size
+NM 			= $(AVR_TOOLS_PATH)/avr-nm
+AVRDUDE 	= $(AVR_TOOLS_PATH)/avrdude
+REMOVE 		= rm -f
+MV 			= mv -f
+
+# Define all object files.
+OBJ = $(SRC:.c=.o) $(CXXSRC:.cpp=.o) $(ASRC:.S=.o)
+OBJ_MODULES = $(C_MODULES:.c=.o) $(CXX_MODULES:.cpp=.o)
+
+# Define all listing files.
+LST = $(ASRC:.S=.lst) $(CXXSRC:.cpp=.lst) $(SRC:.c=.lst)
+
+# Combine all necessary flags and optional flags.
+# Add target processor to flags.
+ALL_CFLAGS 	= $(CFLAGS) -mmcu=$(MCU)
+ALL_CXXFLAGS = $(CXXFLAGS) -mmcu=$(MCU)
+ALL_ASFLAGS = -x assembler-with-cpp $(ASFLAGS) -mmcu=$(MCU)
+ALL_LDFLAGS = $(LDFLAGS) -mmcu=$(MCU)
+
+# Default target.
+# This is th etarget that gets executed with a make command
+# that has no parameters, ie "make".
+all: applet_files build sym lss size upload
+
+build: elf hex
+
+output/$(PROJECT_NAME).cpp: $(PROJECT_NAME).pde
+	test -d output || mkdir output
+	echo "#include <WProgram.h>" > $@ 
+	echo "#line 1 \"$<\"" >> $@ 
+	cat $< >> $@ 
+
+elf: output/$(PROJECT_NAME).elf
+hex: output/$(PROJECT_NAME).hex
+eep: output/$(PROJECT_NAME).eep
+lss: output/$(PROJECT_NAME).lss
+#sym: output/$(PROJECT_NAME).sym
+
+# Upload HEX file to Arduino
+upload: upload1 upload2
+
+upload1: output/$(PROJECT_NAME).hex
+	$(AVRDUDE) $(AVRDUDE_FLAGS) -P $(PORT) $(AVRDUDE_WRITE_FLASH)
+
+upload2: output/$(PROJECT_NAME).hex
+	$(AVRDUDE) $(AVRDUDE_FLAGS) -P $(PORT2) $(AVRDUDE_WRITE_FLASH)
+
+upload3: output/$(PROJECT_NAME).hex
+	$(AVRDUDE) $(AVRDUDE_FLAGS) -P $(PORT3) $(AVRDUDE_WRITE_FLASH)
+
+sym:
+	$(NM) -n -C --format=posix output/$(PROJECT_NAME).elf > output/$(PROJECT_NAME).sym
+	
+# Display size of file.
+size:
+	$(SIZE) output/$(PROJECT_NAME).elf
+	
+# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
+COFFCONVERT=$(OBJCOPY) --debugging \
+--change-section-address .data-0x800000 \
+--change-section-address .bss-0x800000 \
+--change-section-address .noinit-0x800000 \
+--change-section-address .eeprom-0x810000
+
+coff: output/$(PROJECT_NAME).elf
+	$(COFFCONVERT) -O coff-avr output/$(PROJECT_NAME).elf $(PROJECT_NAME).cof
+
+	extcoff: $(PROJECT_NAME).elf
+	$(COFFCONVERT) -O coff-ext-avr output/$(PROJECT_NAME).elf $(PROJECT_NAME).cof
+
+.SUFFIXES: .elf .hex .eep .lss .sym
+
+.elf.hex:
+	$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@
+
+.elf.eep:
+	$(OBJCOPY) -O $(FORMAT) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
+	--no-change-warnings \
+	--change-section-lma .eeprom=0 $< $@
+
+# Create extended listing file from ELF output file.
+.elf.lss:
+	$(OBJDUMP) -h -S $< > $@
+
+# Link: create ELF output file from library.
+#output/$(PROJECT_NAME).elf: $(PROJECT_NAME).c output/core.a
+output/$(PROJECT_NAME).elf: output/$(PROJECT_NAME).o output/core.a
+	$(LD) $(ALL_LDFLAGS) -o $@ output/$(PROJECT_NAME).o output/core.a
+
+output/core.a: $(OBJ_MODULES)
+	@for i in $(OBJ_MODULES); do echo $(AR) rcs output/core.a $$i; $(AR) rcs output/core.a $$i; done
+
+# Compile: create object files from C++ source files.
+.cpp.o:
+	$(CXX) -c $(ALL_CXXFLAGS) $< -o $@
+
+# Compile: create object files from C source files.
+.c.o:
+	$(CC) -c $(ALL_CFLAGS) $< -o $@
+
+# Compile: create assembler files from C source files.
+.c.s:
+	$(CC) -S $(ALL_CFLAGS) $< -o $@
+
+# Assemble: create object files from assembler source files.
+.S.o:
+	$(CC) -c $(ALL_ASFLAGS) $< -o $@
+
+# Automatic dependencies
+%.d: %.c
+	$(CC) -M $(ALL_CFLAGS) $< | sed "s;$(notdir $*).o:;$*.o $*.d:;" > $@
+
+%.d: %.cpp
+	$(CXX) -M $(ALL_CXXFLAGS) $< | sed "s;$(notdir $*).o:;$*.o $*.d:;" > $@
+
+# Target: clean project.
+clean:
+	$(REMOVE) output/$(PROJECT_NAME).hex output/$(PROJECT_NAME).eep output/$(PROJECT_NAME).cof output/$(PROJECT_NAME).elf \
+	output/$(PROJECT_NAME).map output/$(PROJECT_NAME).sym output/$(PROJECT_NAME).lss output/core.a \
+	$(OBJ) $(LST) $(SRC:.c=.s) $(SRC:.c=.d) $(CXXSRC:.cpp=.s) $(CXXSRC:.cpp=.d)
+
+#.PHONY:	all build elf hex eep lss sym program coff extcoff clean applet_files sizebefore sizeafter
+.PHONY:		all build elf hex eep lss sym program coff extcoff applet_files sizebefore sizeafter
+
+#include $(SRC:.c=.d)
+#include $(CXXSRC:.cpp=.d)
diff --git a/examples/scanner/output/core.a b/examples/scanner/output/core.a
new file mode 100644
index 0000000..6ae105d
Binary files /dev/null and b/examples/scanner/output/core.a differ
diff --git a/examples/scanner/output/scanner.cpp b/examples/scanner/output/scanner.cpp
new file mode 100644
index 0000000..5eb1627
--- /dev/null
+++ b/examples/scanner/output/scanner.cpp
@@ -0,0 +1,128 @@
+#include <WProgram.h>
+#line 1 "scanner.pde"
+
+/*
+ Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation.
+ */
+
+/**
+ * Channel scanner
+ *
+ * Example to detect interference on the various channels available.
+ * This is a good diagnostic tool to check whether you're picking a
+ * good channel for your application.
+ *
+ * Inspired by cpixip.
+ * See http://arduino.cc/forum/index.php/topic,54795.0.html
+ */
+
+#include <SPI.h>
+#include "nRF24L01.h"
+#include "RF24.h"
+#include "printf.h"
+
+//
+// Hardware configuration
+//
+
+// Set up nRF24L01 radio on SPI bus plus pins 8 & 9
+
+RF24 radio(8,9);
+
+//
+// Channel info
+//
+
+const short num_channels = 128;
+short values[num_channels];
+
+//
+// Setup
+//
+
+void setup(void)
+{
+  //
+  // Print preamble
+  //
+  
+  Serial.begin(57600);
+  printf_begin();
+  printf("\n\rRF24/examples/scanner/\n\r");
+  
+  //
+  // Setup and configure rf radio
+  //
+  
+  radio.begin();
+  radio.setAutoAck(false);
+
+  // Get into standby mode
+  radio.startListening();
+  radio.stopListening();
+
+  // Print out header, high then low digit 
+  int i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",i>>4);
+    ++i;
+  }
+  printf("\n\r");
+  i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",i&0xf);
+    ++i;
+  }
+  printf("\n\r");
+}
+
+//
+// Loop
+//
+
+const short num_reps = 100;
+
+void loop(void)
+{
+  // Clear measurement values 
+  memset(values,0,num_channels);
+
+  // Scan all channels num_reps times
+  int rep_counter = num_reps;
+  while (rep_counter--)
+  {
+    int i = num_channels;
+    while (i--)
+    {
+      // Select this channel
+      radio.setChannel(i);
+
+      // Listen for a little
+      radio.startListening();
+      delayMicroseconds(128);
+      radio.stopListening();
+
+      // Did we get a carrier?
+      if ( radio.testCarrier() )
+	++values[i];
+    }
+  }
+
+  // Print out channel measurements, clamped to a single hex digit 
+  int i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",min(0xf,values[i]&0xf));
+    ++i;
+  }
+  printf("\n\r");
+}
+
+
+// vim:ai:cin:sts=2 sw=2 ft=cpp
diff --git a/examples/scanner/output/scanner.elf b/examples/scanner/output/scanner.elf
new file mode 100755
index 0000000..5e0f4b1
Binary files /dev/null and b/examples/scanner/output/scanner.elf differ
diff --git a/examples/scanner/output/scanner.hex b/examples/scanner/output/scanner.hex
new file mode 100644
index 0000000..00a3175
--- /dev/null
+++ b/examples/scanner/output/scanner.hex
@@ -0,0 +1,325 @@
+:100000000C9463000C948B000C948B000C948B006C
+:100010000C948B000C948B000C948B000C948B0034
+:100020000C948B000C948B000C948B000C948B0024
+:100030000C948B000C948B000C948B000C948B0014
+:100040000C948F050C948B000C9423060C948B005D
+:100050000C948B000C948B000C948B000C948B00F4
+:100060000C948B000C948B000000000024002700EF
+:100070002A0000000000250028002B0000000000DE
+:1000800023002600290004040404040404040202DA
+:100090000202020203030303030301020408102007
+:1000A0004080010204081020010204081020000012
+:1000B0000007000201000003040600000000000029
+:1000C000000090043B0711241FBECFEFD8E0DEBF35
+:1000D000CDBF11E0A0E0B1E0E6EFF3E102C0059092
+:1000E0000D92AA33B107D9F712E0AAE3B1E001C03B
+:1000F0001D92A13FB107E1F710E0C6ECD0E004C0CB
+:100100002297FE010E94F509C23CD107C9F70E945F
+:100110001C060C94F9090C9400000F931F93CF93C5
+:10012000DF938C01EB01009731F46115710519F42F
+:1001300020E030E038C081E090E06EE070E00E94A6
+:10014000CB02FC019C01009771F180E8838320972A
+:1001500071F0D387C28781E883838091E702909111
+:10016000E802892B21F4F093E802E093E7020115FD
+:100170001105C9F011870087838182608383809194
+:10018000E9029091EA02892B71F4F093EA02E0937C
+:10019000E9028091EB029091EC02892B21F4F0931B
+:1001A000EC02E093EB02C901DF91CF911F910F9117
+:1001B0000895A0E0B0E0EFEDF0E00C94CC09FE0172
+:1001C0003596619171918091E9029091EA02AF01B7
+:1001D0000E94EE002096E2E00C94E809ABE0B0E06B
+:1001E000E4EFF0E00C94BC093C012B015A01FC0146
+:1001F00017821682838181FD03C06FEF7FEFC6C136
+:100200009AE0892E1E010894211C311CF3012381E0
+:10021000F20123FD859123FF81912F01882309F4A9
+:10022000B2C1853239F423FD859123FF81912F01DD
+:10023000853229F490E0B3010E940604E7CF982F9D
+:10024000FF24EE249924FFE1FF15D0F09B3269F0E2
+:100250009C3228F4903259F0933291F40EC09D32C2
+:1002600049F0903369F441E024C052E0F52A84E07B
+:10027000F82A28C098E0F92A25C0E0E1FE2A22C029
+:10028000F7FC29C0892F80538A3070F4F6FE05C030
+:10029000989C902C1124980E15C0E89CE02C1124F9
+:1002A000E80EF0E2FF2A0EC09E3229F4F6FC6BC184
+:1002B00040E4F42A07C09C3619F450E8F52A02C03D
+:1002C000983649F4F20123FD959123FF91912F0176
+:1002D000992309F0B8CF892F8554833018F08052C4
+:1002E000833038F444E050E0A40EB51E5FE3598338
+:1002F0000FC0933631F0933779F0933509F056C03B
+:1003000020C0F5018081898342E050E0A40EB51E33
+:10031000610101E010E012C0F501C080D180F6FC5F
+:1003200003C06FEF7FEF02C0692D70E042E050E044
+:10033000A40EB51EC6010E94FB038C015FE7F522E7
+:1003400014C0F501C080D180F6FC03C06FEF7FEFD1
+:1003500002C0692D70E042E050E0A40EB51EC60157
+:100360000E94E9038C0150E8F52AF3FE07C01AC089
+:1003700080E290E0B3010E940604EA948E2D90E0A2
+:1003800008171907A8F30EC0F601F7FC8591F7FED0
+:1003900081916F0190E0B3010E940604E110EA949C
+:1003A000015010400115110579F7EAC0943611F09B
+:1003B000993669F5F7FE08C0F50120813181428147
+:1003C000538184E090E00AC0F501808191819C0115
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diff --git a/examples/scanner/printf.h b/examples/scanner/printf.h
new file mode 100644
index 0000000..63501e4
--- /dev/null
+++ b/examples/scanner/printf.h
@@ -0,0 +1,33 @@
+/*
+ Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation.
+ */
+ 
+/**
+ * @file printf.h
+ *
+ * Setup necessary to direct stdout to the Arduino Serial library, which
+ * enables 'printf'
+ */
+
+#ifndef __PRINTF_H__
+#define __PRINTF_H__
+
+#include "WProgram.h"
+
+int serial_putc( char c, FILE *t ) 
+{
+  Serial.write( c );
+
+  return c;
+} 
+
+void printf_begin(void)
+{
+  fdevopen( &serial_putc, 0 );
+}
+
+#endif // __PRINTF_H__
diff --git a/examples/scanner/scanner.pde b/examples/scanner/scanner.pde
new file mode 100644
index 0000000..efefa17
--- /dev/null
+++ b/examples/scanner/scanner.pde
@@ -0,0 +1,125 @@
+
+/*
+ Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation.
+ */
+
+/**
+ * Channel scanner
+ *
+ * Example to detect interference on the various channels available.
+ * This is a good diagnostic tool to check whether you're picking a
+ * good channel for your application.
+ *
+ * Inspired by cpixip.
+ * See http://arduino.cc/forum/index.php/topic,54795.0.html
+ */
+
+#include <SPI.h>
+#include "nRF24L01.h"
+#include "RF24.h"
+#include "printf.h"
+
+//
+// Hardware configuration
+//
+
+// Set up nRF24L01 radio on SPI bus plus pins 8 & 9
+
+RF24 radio(8,9);
+
+//
+// Channel info
+//
+
+const short num_channels = 128;
+short values[num_channels];
+
+//
+// Setup
+//
+
+void setup(void)
+{
+  //
+  // Print preamble
+  //
+  
+  Serial.begin(57600);
+  printf_begin();
+  printf("\n\rRF24/examples/scanner/\n\r");
+  
+  //
+  // Setup and configure rf radio
+  //
+  
+  radio.begin();
+  radio.setAutoAck(false);
+
+  // Get into standby mode
+  radio.startListening();
+  radio.stopListening();
+
+  // Print out header, high then low digit 
+  int i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",i>>4);
+    ++i;
+  }
+  printf("\n\r");
+  i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",i&0xf);
+    ++i;
+  }
+  printf("\n\r");
+}
+
+//
+// Loop
+//
+
+const short num_reps = 100;
+
+void loop(void)
+{
+  // Clear measurement values 
+  memset(values,0,num_channels);
+
+  // Scan all channels num_reps times
+  int rep_counter = num_reps;
+  while (rep_counter--)
+  {
+    int i = num_channels;
+    while (i--)
+    {
+      // Select this channel
+      radio.setChannel(i);
+
+      // Listen for a little
+      radio.startListening();
+      delayMicroseconds(128);
+      radio.stopListening();
+
+      // Did we get a carrier?
+      if ( radio.testCarrier() )
+	++values[i];
+    }
+  }
+
+  // Print out channel measurements, clamped to a single hex digit 
+  int i = 0;
+  while ( i < num_channels )
+  {
+    printf("%x",min(0xf,values[i]&0xf));
+    ++i;
+  }
+  printf("\n\r");
+}
+
+// vim:ai:cin:sts=2 sw=2 ft=cpp