Added mapping tables for the intake/exhaust valves

ArduinoFreevalve/ArduinoFreevalve.ino

@@ -0,0 +1,83 @@
+// An Arduino program for controlling valve timing on a 6.5HP Predator engine from Harbor Freight.
+//
+// License goes here.
+//
+// Wesley Kagan, 2020
+// Ric Allinson, 2020
+
+// Pins assignment.
+static const int HALL_MAGNET = 2;
+static const int ROTATION_MAGNET = 3;
+static const int EXHAUST_V = 12;
+static const int INTAKE_V = 13;
+
+// Implementation constants (to be changed by implementer).
+static const int NUM_STEPS = 60;
+
+// Control constants.
+static const int STEPS_PER_ROTATION = NUM_STEPS - 1; // Number of interrupts in a half cycle for a zero based array.
+static const int STEPS_PER_CYCLE = NUM_STEPS * 2;    // Number of interrupts in the full cycle.
+
+// Runtime mapping variables.
+bool intakeMap[STEPS_PER_CYCLE] = {};  // Intake open/close mapping is equal the total number of interrupts for two rotations.
+bool exhaustMap[STEPS_PER_CYCLE] = {}; // Exhaust open/close mapping is equal the total number of interrupts for two rotations.
+
+// ISR variables.
+volatile int hallCounter = 0;      // The number of magnets after the last TDC.
+volatile bool secondCycle = false; // "true" if the cam is on its second rotation.
+volatile bool printLog = false;    // Used to stop duplicate values from printing in the loop.
+
+void setup() {
+  Serial.begin(115200);
+  pinMode(HALL_MAGNET, INPUT);
+  attachInterrupt(0, rotationDetect, RISING);
+  attachInterrupt(1, magnetDetect, RISING);
+  pinMode(INTAKE_V, OUTPUT);
+  pinMode(EXHAUST_V, OUTPUT);
+  /* 
+    Load mappings here.
+  */
+  // intakeMap = ?
+  // exhaustMap = ?
+}
+
+void loop() {
+  // This may not print the correct values. Only the most recent from the last magnetDetect() interrupt.
+  if(printLog){
+    Serial.print(hallCounter);
+    Serial.println(secondCycle);
+    printLog = false;
+  }
+}
+
+// This function is called once per rotation.
+void rotationDetect() {
+  if (secondCycle) {
+    hallCounter = 0;                  // On the second cycle reset the hallCounter.
+  } else {
+    hallCounter = STEPS_PER_ROTATION; // Forcing the counter in case of drift over a rotation.
+  }
+  // Flip the secondCycle flag.
+  secondCycle = !secondCycle;
+}
+
+// This function is called NUM_STEPS per rotation.
+// This function will be called about every ~263.16usec at the maximum RPM of 3800.
+// (1 rev / 60 pulses) * (1 min / 3800 rev) * (60 sec / min) = 1 / 3800 sec/pulse = ~263.16usec.
+void magnetDetect() {
+  // Increment the counter to keep track of the position.
+  hallCounter++;
+
+  // If the hallCounter is greater than the mapping index reset it.
+  // This would only happen when the rotationDetect() interrupt was NOT triggered.
+  if (hallCounter >= STEPS_PER_CYCLE) {
+    hallCounter = 0;
+  }
+
+  // Use the intake/exhaust maps to open or close the valves.
+  digitalWrite(INTAKE_V, intakeMap[hallCounter]);
+  digitalWrite(EXHAUST_V, exhaustMap[hallCounter]);
+
+  // Tells the loop() that the ISR variables have changed.
+  printLog = true;
+}

README.md

@@ -1,4 +1,15 @@
+# Arduino Freevalve
+
+Repository for the Arduino Freevalve Project at www.youtube.com/c/wesleykagan 
+
+## Overview
+
+This code is tested with the [Harbor Freight 6.5hp 212cc OHC Horizontal Shaft Gas Engine EPA&CARB](https://www.harborfreight.com/engines-generators/gasoline-engines/65-hp-212cc-ohv-horizontal-shaft-gas-engine-epacarb-69727.html)
+
+## Original README
+
 # Freevalve_Arduino
+
 Codebase for the Arduino Freevalve Project- found here: www.youtube.com/c/wesleykagan 
 
 Okay, so this is a super early stage of this project, but as of this post, it does work in the 
@@ -25,4 +36,4 @@ Website: www.wesleykagan.com
 
 For promotional inquiries: [email protected]
 
-USE AT YOUR OWN RISK!
+USE AT YOUR OWN RISK!