launchControl.ino

/**
 * Arduino based "2-step launch control"
 * Works by interrupt power signal to ignition coil.
 * Requires RPM and Clutch signal
 *
 * @author Birkir Gudjonsson (birkir.gudjonsson@gmail.com)
 * @licence http://en.wikipedia.org/wiki/BSD_licenses
 */
 
// settings
int launch = 4000; // rpm to launch at
int step = 25 * 1000; // 25ms stepper
 
// inputs
int injectorPin = 1; // injector signal
int clutchPin = 2; // clutch
 
// outputs
int ignitionCoilPin = 4; // ignition coil power (using MOSFET)
 
// variables
int rpm = 0;
unsigned long lastInterruptTime;
 
// setup
void setup()
{
  // attach interrupt to injectors
  attachInterrupt(injectorPin, rpmCalculation, RISING);
 
  // set clutch mode
  setPin(clutchPin, INPUT);
 
  // set ign coil as output
  setPin(ignitionCoilPin, OUTPUT);
 
  // enable by default
  digitalWrite(ignitionCoilPin, HIGH);
 
  // wait 5 seconds
  delay(5000);
}
 
// loop
void loop()
{
  // check if actual rpm is equal or greater than launch rpm, and if clutch petal is down
  if (rpm >= launch && digitalRead(clutchPin) == HIGH)
  {
    // cut power to ignition coil for some milliseconds.
    digitalWrite(ignitionCoilPin, LOW);
    delayMicroseconds(step);
    digitalWrite(ignitionCoilPin, HIGH);
    delayMicroseconds(step);
  }
}
 
// calculate rpm
void rpmCalculation()
{
  unsigned long now = micros();
 
  rpm = 60 / ((now - lastInterruptTime) / 1000000) / 2;
 
  lastInterruptTime = now;
}

Why interrupt the injectors? Just interrupting the ignition coil power should work. Anyways awesome project that I will defiantly try out!

halo . when i try to verify the program it gives me an error saying set pin was not declared in this scope, it gives the line error on line 32. i am fairly new to programming so a little help would we grate !

Adriaankenny
try to replace setPin with pinMode

Thank you , now you say you use an injector signal as input , would an rpm input work ? taping into rpm output from the ecu ? it is a 12 v square wave , will this damage the board ?

not work rpm calculation