Dual wheel decoder

decoders.h

@@ -1,14 +1,19 @@
+#define TOOTH_HISTORY_LENGTH 512
+
 volatile unsigned long curTime;
 volatile unsigned int curGap;
+volatile unsigned long curTime2;
+volatile unsigned int curGap2;
 volatile unsigned int lastGap;
 volatile unsigned int targetGap; 
 
 volatile int toothCurrentCount = 0; //The current number of teeth (Onec sync has been achieved, this can never actually be 0
 volatile unsigned long toothLastToothTime = 0; //The time (micros()) that the last tooth was registered
+volatile unsigned long toothLastSecToothTime = 0; //The time (micros()) that the last tooth was registered on the secondary input
 volatile unsigned long toothLastMinusOneToothTime = 0; //The time (micros()) that the tooth before the last tooth was registered
 volatile unsigned long toothOneTime = 0; //The time (micros()) that tooth 1 last triggered
 volatile unsigned long toothOneMinusOneTime = 0; //The 2nd to last time (micros()) that tooth 1 last triggered
-volatile unsigned int toothHistory[512];
+volatile unsigned int toothHistory[TOOTH_HISTORY_LENGTH];
 volatile unsigned int toothHistoryIndex = 0;
 
 volatile byte secondaryToothCount; //Used for identifying the current secondary (Usually cam) tooth for patterns with multiple secondary teeth
@@ -16,6 +21,7 @@ volatile unsigned long secondaryLastToothTime = 0; //The time (micros()) that th
 
 volatile int triggerActualTeeth;
 unsigned int triggerFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering)
+unsigned int triggerSecFilterTime; // The shortest time (in uS) that pulses will be accepted (Used for debounce filtering) for the secondary input
 unsigned int triggerToothAngle; //The number of crank degrees that elapse per tooth
 unsigned long revolutionTime; //The time in uS that one revolution would take at current speed (The time tooth 1 was last seen, minus the time it was seen prior to that)
 

decoders.ino

@@ -30,6 +30,7 @@ void triggerSetup_missingTooth()
 {
   triggerToothAngle = 360 / configPage2.triggerTeeth; //The number of degrees that passes from tooth to tooth
   triggerActualTeeth = configPage2.triggerTeeth - configPage2.triggerMissingTeeth; //The number of physical teeth on the wheel. Doing this here saves us a calculation each time in the interrupt
+  triggerFilterTime = (int)(1000000 / (MAX_RPM / 60 * configPage2.triggerTeeth)); //Trigger filter time is the shortest possible time (in uS) that there can be between crank teeth (ie at max RPM). Any pulses that occur faster than this time will be disgarded as noise
 }
 
 void triggerPri_missingTooth()
@@ -98,13 +99,88 @@ int getCrankAngle_missingTooth(int timePerDegree)
 }
 
 /* 
-Name: Missing tooth wheel
-Desc: A multi-tooth wheel with one of more 'missing' teeth. The first tooth after the missing one is considered number 1 and isthe basis for the trigger angle
-Note: This does not currently support dual wheel (ie missing tooth + single tooth on cam)
+Name: Dual wheel
+Desc: 2 wheels located either both on the crank or with the primary on the crank and the secondary on the cam. 
+Note: There can be no missing teeth on the primary wheel
 */
+void triggerSetup_DualWheel()
+{
+  triggerToothAngle = 360 / configPage2.triggerTeeth; //The number of degrees that passes from tooth to tooth
+  toothCurrentCount = 255; //Default value
+  triggerFilterTime = (int)(1000000 / (MAX_RPM / 60 * configPage2.triggerTeeth)); //Trigger filter time is the shortest possible time (in uS) that there can be between crank teeth (ie at max RPM). Any pulses that occur faster than this time will be disgarded as noise
+  triggerSecFilterTime = (int)(1000000 / (MAX_RPM / 60 * 2)) / 2; //Same as above, but fixed at 2 teeth on the secondary input and divided by 2 (for cam speed)
+}
+
+
 void triggerPri_DualWheel()
 { 
-  return;
+   curTime = micros();
+   curGap = curTime - toothLastToothTime;
+   if ( curGap < triggerFilterTime ) { 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
+   
+   if ( toothCurrentCount == 1 || toothCurrentCount > configPage2.triggerTeeth)
+   { 
+     toothCurrentCount = 1; 
+     toothOneMinusOneTime = toothOneTime;
+     toothOneTime = curTime;
+     startRevolutions++; //Counter
+     if ((startRevolutions & 63) == 1) { currentStatus.hasSync = false; } //Every 64 revolutions, force a resync with the cam
+   } 
+   
+   //High speed tooth logging history
+   toothHistory[toothHistoryIndex] = curGap;
+   if(toothHistoryIndex == 511)
+   { toothHistoryIndex = 0; }
+   else
+   { toothHistoryIndex++; }
+   
+   toothLastMinusOneToothTime = toothLastToothTime;
+   toothLastToothTime = curTime;
+}
+
+void triggerSec_DualWheel()
+{ 
+  curTime2 = micros();
+  curGap2 = curTime2 - toothLastSecToothTime;
+  if ( curGap2 < triggerSecFilterTime ) { return; } 
+  toothLastSecToothTime = curTime2;
+  
+  if(!currentStatus.hasSync)
+  {
+    toothCurrentCount = 0;
+    currentStatus.hasSync = true;
+  }
+} 
+
+int getRPM_DualWheel()
+{
+   noInterrupts();
+   revolutionTime = (toothOneTime - toothOneMinusOneTime); //The time in uS that one revolution would take at current speed (The time tooth 1 was last seen, minus the time it was seen prior to that)
+   interrupts(); 
+   return (US_IN_MINUTE / revolutionTime); //Calc RPM based on last full revolution time (Faster as /)
+}
+
+int getCrankAngle_DualWheel(int timePerDegree)
+{
+    //This is the current angle ATDC the engine is at. This is the last known position based on what tooth was last 'seen'. It is only accurate to the resolution of the trigger wheel (Eg 36-1 is 10 degrees)
+    unsigned long tempToothLastToothTime;
+    int tempToothCurrentCount;
+    //Grab some variables that are used in the trigger code and assign them to temp variables. 
+    noInterrupts();
+    tempToothCurrentCount = toothCurrentCount;
+    tempToothLastToothTime = toothLastToothTime;
+    interrupts();
+    
+    //Handle case where the secondary tooth was the last one seen
+    if(tempToothCurrentCount == 0) { tempToothCurrentCount = configPage2.triggerTeeth; }
+    
+    int crankAngle = (tempToothCurrentCount - 1) * triggerToothAngle + configPage2.triggerAngle; //Number of teeth that have passed since tooth 1, multiplied by the angle each tooth represents, plus the angle that tooth 1 is ATDC. This gives accuracy only to the nearest tooth.
+    crankAngle += ( (micros() - tempToothLastToothTime) / timePerDegree); //Estimate the number of degrees travelled since the last tooth
+
+    if (crankAngle > 360) { crankAngle -= 360; }
+    
+    return crankAngle;
 }
 
 

reference/speeduino.ini

@@ -605,7 +605,7 @@ page = 7
    dialog = triggerSettings,"Trigger Settings",4
       topicHelp = Shelp3
       field = "Trigger Pattern",                TrigPattern
-      field = "Primary base teeth",             numteeth,       { TrigPattern == 0 }
+      field = "Primary base teeth",             numteeth,       { TrigPattern == 0 || TrigPattern == 2 }
       field = "Primary trigger speed",          TrigSpeed,      { TrigPattern == 0 }
       field = "Missing teeth",                  onetwo,         { TrigPattern == 0 }
       field = "Secondary teeth",                onetwo,         { TrigPattern == 2 }

speeduino.ino

@@ -181,7 +181,7 @@ void setup()
   currentStatus.hasSync = false;
   currentStatus.runSecs = 0; 
   currentStatus.secl = 0;
-  triggerFilterTime = (int)(1000000 / (MAX_RPM / 60 * configPage2.triggerTeeth)); //Trigger filter time is the shortest possible time (in uS) that there can be between crank teeth (ie at max RPM). Any pulses that occur faster than this time will be disgarded as noise
+  triggerFilterTime = 0; //Trigger filter time is the shortest possible time (in uS) that there can be between crank teeth (ie at max RPM). Any pulses that occur faster than this time will be disgarded as noise. This is simply a default value, the actual values are set in the setup() functinos of each decoder
   
   switch (pinTrigger) {  
     //Arduino Mega 2560 mapping
@@ -247,7 +247,14 @@ void setup()
       break;
           
     case 2:
+      triggerSetup_DualWheel();
       trigger = triggerPri_DualWheel;
+      getRPM = getRPM_DualWheel;
+      getCrankAngle = getCrankAngle_DualWheel;
+      
+      if(configPage2.TrigEdge == 0) { attachInterrupt(triggerInterrupt, trigger, RISING); } // Attach the crank trigger wheel interrupt (Hall sensor drags to ground when triggering)
+      else { attachInterrupt(triggerInterrupt, trigger, FALLING); }
+      attachInterrupt(triggerInterrupt2, triggerSec_DualWheel, RISING);
       break;
       
     case 3: