Calculate Volumetric Flow Through Orifice Flowmeter

double CalcFlowmeter(double CfA0, double dP, double density, double offset) {

  return CfA0*sqrt(((dP-offset)*2)/density);

}

where:

CfAo is determined through flowmeter calibration

dP is the differential pressure across the flowmeter (from Press_Data[i]) in Pascals

density is the density of the gas (1.2 kg/m3 for air, estimated to be 0.95 for wood gas)

offset is the zero offset for the pressure sensor. The zero offset does fluctate with time, ideally the offset should be found before each run (no flow condition)

Manually Pulse Servo

Pending library support for servo control, you can manually control a Futaba servo:

void PulseServo(int servo_pin,double angle) {

  // manually pulse servo - up to 2 ms delay will be be an issue w/ more then a few servos, may be ok w/ 3.

  digitalWrite(servo_pin,HIGH);

  delayMicroseconds(1000+angle*5.556);

  digitalWrite(SERVO0,LOW);

}