int percentanalog = A0; // 0-5 Volt input from pot
int tempanalog = A1; // 0-5 Volt input from pot
int outputpin = 8; // output pin assignment
int val = 0; // place holder to read analog inputs
int outputState = LOW; // set output to false
unsigned long previousMicros = 0; // save the last time the output was switched


void setup() {
Serial.begin(9600); // setup serial comms
pinMode(outputpin, OUTPUT); // setup output

}

void loop() {

// convert analog input to flex fuel percent 0-100 %
val = analogRead(percentanalog);
float flexpercent = (val*0.0977517);

// convert analog input to ms of low time for fuel temp 1-5 ms (1ms -40c and 5ms 125c)
val = analogRead(tempanalog);
float fueltemp = (val*0.00391007) + 1;

// calculate period from the frequency (flex percent + 50) and converted to microseconds
float period = (1 / (flexpercent + 50)) * 1000000;

// low time is calculated from the fuel temp and converted to microseconds
float lowtime = fueltemp * 1000;

// subtrack lowtime from the signal period time
float hightime = period - lowtime;

// grab current time in microseconds
unsigned long currentMicros = micros();

// determine the elapsed time since the last time the output was switched
unsigned long elapsedtime = currentMicros - previousMicros;

if (outputState == LOW){
if(elapsedtime >= lowtime){
digitalWrite(outputpin, HIGH); // sets the output high
outputState = HIGH;
previousMicros = currentMicros; // save the "current" time
}
}

else {
if(elapsedtime >= hightime){
outputState = LOW; // "toggles" the state
digitalWrite(outputpin, LOW); // sets the output low
outputState = LOW;
previousMicros = currentMicros; // save the "current" time
}
}

// printing causes timing issues, so these were only used for debugging

// if (outputState)
// Serial.println(1);
// else
// Serial.println(0);

// Serial.println(period,4);
// Serial.println(hightime,8);
// Serial.println(lowtime,8);
// Serial.println(flexpercent);
// Serial.println(fueltemp);

}