diff --git a/comms.h b/comms.h
index b685f1c..a0f93c6 100644
--- a/comms.h
+++ b/comms.h
@@ -1,3 +1,6 @@
+#ifndef COMMS_H
+#define COMMS_H
+
 #define vePage    1
 #define ignPage   2
 #define afrPage   3
@@ -12,3 +15,5 @@ void sendPage();
 void receiveCalibration(byte tableID);
 void sendToothLog(bool useChar);
 void testComm();
+
+#endif // COMMS_H
diff --git a/comms.ino b/comms.ino
index 3e9cda1..f79efed 100644
--- a/comms.ino
+++ b/comms.ino
@@ -3,6 +3,10 @@ This is called when a command is received over serial from TunerStudio / Megatun
 It parses the command and calls the relevant function
 A detailed description of each call can be found at: http://www.msextra.com/doc/ms1extra/COM_RS232.htm
 */
+#include "comms.h"
+#include "globals.h"
+#include "storage.h"
+
 void command()
 {
   switch (Serial.read()) 
diff --git a/corrections.h b/corrections.h
index 3e24b0a..0fd54ba 100644
--- a/corrections.h
+++ b/corrections.h
@@ -2,6 +2,9 @@
 All functions in the gamma file return 
 
 */
+#ifndef CORRECTIONS_H
+#define CORRECTIONS_H
+
 //static byte numCorrections = 2;
 
 byte correctionsTotal();
@@ -10,3 +13,5 @@ byte correctionASE(); //After Start Enrichment
 byte correctionAccel(); //Acceleration Enrichment
 byte correctionsFloodClear(); //Check for flood clear on cranking
 byte correctionsAFRClosedLoop(); //Closed loop AFR adjustment
+
+#endif // CORRECTIONS_H
diff --git a/corrections.ino b/corrections.ino
index f003c30..78dcbc6 100644
--- a/corrections.ino
+++ b/corrections.ino
@@ -7,6 +7,8 @@ Flood clear mode etc.
 */
 //************************************************************************************************************
 
+#include "corrections.h"
+#include "globals.h"
 
 /*
 correctionsTotal() calls all the other corrections functions and combines their results.
diff --git a/fastAnalog.h b/fastAnalog.h
index af6fbb1..b1b0ef9 100644
--- a/fastAnalog.h
+++ b/fastAnalog.h
@@ -1,3 +1,6 @@
+#ifndef FASTANALOG_H
+#define FASTANALOG_H
+
 #ifndef cbi
 #define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
 #endif
@@ -5,4 +8,5 @@
 #define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
 #endif
 
+#endif // FASTANALOG_H
 
diff --git a/globals.h b/globals.h
index 7ba915a..a6d6207 100644
--- a/globals.h
+++ b/globals.h
@@ -1,3 +1,5 @@
+#ifndef GLOBALS_H
+#define GLOBALS_H
 #include <Arduino.h>
 
 const byte ms_version = 20;
@@ -270,3 +272,25 @@ struct config3 {
 #define pinCLT A3 //CLS sensor pin
 #define pinO2 A4 //O2 Sensor pin
 */
+
+// global variables // from speeduino.ino
+extern struct statuses currentStatus; // from speeduino.ino
+extern struct table3D fuelTable; //8x8 fuel map
+extern struct table3D ignitionTable; //8x8 ignition map
+extern struct table3D afrTable; //8x8 afr target map
+extern struct table2D taeTable; //4 bin TPS Acceleration Enrichment map
+extern struct table2D WUETable; //10 bin Warm Up Enrichment map (2D)
+extern struct config1 configPage1;
+extern struct config2 configPage2;
+extern struct config3 configPage3;
+extern unsigned long currentLoopTime; //The time the current loop started (uS)
+extern unsigned long previousLoopTime; //The time the previous loop started (uS)
+extern byte ignitionCount;
+extern byte cltCalibrationTable[CALIBRATION_TABLE_SIZE];
+extern byte iatCalibrationTable[CALIBRATION_TABLE_SIZE];
+extern byte o2CalibrationTable[CALIBRATION_TABLE_SIZE];
+extern volatile int toothHistory[512];
+extern volatile int toothHistoryIndex;
+
+
+#endif // GLOBALS_H
diff --git a/math.h b/math.h
index fe25096..316ac60 100644
--- a/math.h
+++ b/math.h
@@ -1,3 +1,5 @@
+#ifndef MATH_H
+#define MATH_H
 
 //Replace the standard arduino map() function to use the div function instead
 int fastMap(int x, int in_min, int in_max, int out_min, int out_max)
@@ -49,3 +51,5 @@ int divs100(int n) {
  return q + ((r + 28) >> 7);
 // return q + (r > 99);
 }
+
+#endif // MATH_H
diff --git a/scheduler.h b/scheduler.h
index 4d3e9eb..d6257c0 100644
--- a/scheduler.h
+++ b/scheduler.h
@@ -22,6 +22,8 @@ See page 136 of the processors datasheet: http://www.atmel.com/Images/doc2549.pd
 256 prescale gives overflow every 1048576uS (This means maximum wait time is 1.0485 seconds)
 
 */
+#ifndef SCHEDULER_H
+#define SCHEDULER_H
 
 #include <avr/interrupt.h> 
 #include <avr/io.h>
@@ -54,3 +56,5 @@ Schedule ignitionSchedule1;
 Schedule ignitionSchedule2;
 Schedule ignitionSchedule3;
 Schedule ignitionSchedule4;
+
+#endif // SCHEDULER_H
diff --git a/scheduler.ino b/scheduler.ino
index 5a20889..2c74e71 100644
--- a/scheduler.ino
+++ b/scheduler.ino
@@ -1,4 +1,5 @@
-
+#include "scheduler.h"
+#include "globals.h"
 
 
 void initialiseSchedulers()
diff --git a/speeduino.ino b/speeduino.ino
index 7b99565..7129c9e 100644
--- a/speeduino.ino
+++ b/speeduino.ino
@@ -540,7 +540,7 @@ void endCoil4Charge() { digitalWrite(pinCoil4, coilLOW); BIT_CLEAR(currentStatus
 
 //The trigger function is called everytime a crank tooth passes the sensor
 volatile unsigned long curTime;
-volatile int curGap;
+volatile unsigned int curGap;
 volatile unsigned int targetGap; 
 void trigger()
   {
@@ -550,7 +550,7 @@ void trigger()
 
    curTime = micros();
    curGap = curTime - toothLastToothTime;
-   if ( curGap < triggerFilterTime) { interrupts(); return; } //Debounce check. Pulses should never be less than triggerFilterTime, so if they are it means a false trigger. (A 36-1 wheel at 8000pm will have triggers approx. every 200uS)
+   if ( curGap < triggerFilterTime ) { interrupts(); return; } //Debounce check. Pulses should never be less than triggerFilterTime, so if they are it means a false trigger. (A 36-1 wheel at 8000pm will have triggers approx. every 200uS)
    toothCurrentCount++; //Increment the tooth counter
    
    //High speed tooth logging history
diff --git a/storage.h b/storage.h
index 1100d27..499d46f 100644
--- a/storage.h
+++ b/storage.h
@@ -1,3 +1,5 @@
+#ifndef STORAGE_H
+#define STORAGE_H
 #include <EEPROM.h>
 
 void writeConfig();
@@ -59,3 +61,4 @@ Current layout of EEPROM data (Version 2) is as follows (All sizes are in bytes)
 #define EEPROM_CALIBRATION_IAT 3071
 #define EEPROM_CALIBRATION_CLT 3583
 
+#endif // STORAGE_H
diff --git a/storage.ino b/storage.ino
index bd97061..39df0c2 100644
--- a/storage.ino
+++ b/storage.ino
@@ -1,6 +1,9 @@
 #include <EEPROM.h>
+#include "storage.h"
+#include "globals.h"
 //#include "table.h"
 
+
 /*
 Takes the current configuration (config pages and maps)
 and writes them to EEPROM as per the layout defined in storage.h
diff --git a/table.h b/table.h
index 66166f4..8170abc 100644
--- a/table.h
+++ b/table.h
@@ -1,6 +1,8 @@
 /*
 This file is used for everything related to maps/tables including their definition, functions etc
 */
+#ifndef TABLE_H
+#define TABLE_H
 #include <Arduino.h>
 
 /*
@@ -46,3 +48,5 @@ Eg: 2x2 table
 */
 int get3DTableValue(struct table3D, int, int);
 int table2D_getValue(struct table2D, int);
+
+#endif // TABLE_H
diff --git a/table.ino b/table.ino
index 909d004..1f38228 100644
--- a/table.ino
+++ b/table.ino
@@ -2,6 +2,9 @@
 Because the size of the table is dynamic, this functino is required to reallocate the array sizes
 Note that this may clear some of the existing values of the table
 */
+#include "table.h"
+#include "globals.h"
+
 void table2D_setSize(struct table2D* targetTable, byte newSize)
 {
   //2D tables can contain either bytes or ints, depending on the value of the valueSize field
diff --git a/testing.h b/testing.h
index 2f9633e..53b6473 100644
--- a/testing.h
+++ b/testing.h
@@ -1,7 +1,8 @@
 /*
 This file has a few functions that are helpful for testing such as creating dummy maps and faking interrupts
 */
-
+#ifndef TESTING_H
+#define TESTING_H
 /*
 Aim is to create an 8x8 table that looks like the below:
  MAP
@@ -105,3 +106,5 @@ void dummyIgnitionTable(struct table3D *mySparkTable)
     for (byte x = 0; x< mySparkTable->xSize; x++) { mySparkTable->values[7][x] = tempRow8[x]; }
         
   }
+
+#endif // TESTING_H
diff --git a/timers.h b/timers.h
index 5660c31..41d0671 100644
--- a/timers.h
+++ b/timers.h
@@ -16,6 +16,8 @@ We're after a 1ms interval so we'll need 131 intervals to reach this ( 1ms / 0.0
 Hence we will preload the timer with 131 cycles to leave 125 until overflow (1ms).
 
 */
+#ifndef TIMERS_H
+#define TIMERS_H
 
 volatile int loop250ms;
 volatile int loopSec;
@@ -24,4 +26,4 @@ volatile unsigned long targetOverdwellTime;
 
 void initialiseTimers();
 
-
+#endif // TIMERS_H
diff --git a/timers.ino b/timers.ino
index 552a113..12eb189 100644
--- a/timers.ino
+++ b/timers.ino
@@ -4,6 +4,8 @@ They should not be confused with Schedulers, which are for performing an action
 
 Timers are typically low resolution (Compared to Schedulers), with maximum frequency currently being approximately every 10ms
 */
+#include "timers.h"
+#include "globals.h"
 
 void initialiseTimers() 
 {  
diff --git a/utils.h b/utils.h
index b44b396..49746fa 100644
--- a/utils.h
+++ b/utils.h
@@ -1,6 +1,9 @@
 /*
 These are some utility functions and variables used through the main code
 */ 
+#ifndef UTILS_H
+#define UTILS_H
+
 #include <Arduino.h>
 #define MS_IN_MINUTE 60000
 #define US_IN_MINUTE 60000000
@@ -10,3 +13,5 @@ int AIRDEN();
 unsigned int PW();
 unsigned int PW_SD();
 unsigned int PW_AN();
+
+#endif // UTILS_H
diff --git a/utils.ino b/utils.ino
index 8a184e7..6f23a14 100644
--- a/utils.ino
+++ b/utils.ino
@@ -1,6 +1,8 @@
 /*
 Returns how much free dynamic memory exists (between heap and stack)
 */
+#include "utils.h"
+
 int freeRam () 
 {
   extern int __heap_start, *__brkval;