Arduino code for the Columbia DIY Ventilator Challenge

vent_code.ino

int bpm = 30; // breaths per minute; can be changed by clinician

// sensors
int presLimit = 100; // [g], limit for pressure sensor
int colorLimit = 200; // limit for color sensor
int FSRSeries = 10000; // resistor value in series w/ FSR
float presLimitVoltage = FSRSeries/(FSRSeries + 8000);
float colorLimitVoltage = (colorLimit/256)*5;
float presVoltage = 0;
int redValue = 0;
int previousRed = 0;

// motor specs
float wormGear = 1/4;
int gearbox = 40;
int noloadRPM = 150;

int MotorPWM = (255*bpm/(noloadRPM*wormGear));

// color sensor pins
#define greenPin A2
#define redPin A3
#define bluePin A1

#define FSRPin A4
#define SpeakerPin 1
#define MotorInput 2

// buttons
#define upButton 8
#define downButton 9
#define EStop 10


void setup() {
  digitalWrite(SpeakerPin, LOW);
  pinMode(MotorInput, OUTPUT);
}

void loop() {
// motor control using PWM
  analogWrite(MotorInput, MotorPWM);

// read pressure from FSR: voltage divider
  presVoltage = FSRSeries/(FSRSeries + A4);

// read color from sensor
  redValue = redPin;

if ((redValue > colorLimitVoltage) and (previousRed > colorLimitVoltage)
  or (presVoltage < presLimitVoltage) or (EStop == LOW)) {
  // if the color sensor detects red for two consecutive cycles, 
  // the manometer has been in the low position too long
  // or, if the bag is no longer being pressed into the table, 
  // there's a leak
  tone(SpeakerPin, 440, 1000); // plays A440
}

if (downButton == LOW){
  bpm -= 1;
}
if (upButton == HIGH){
  bpm +=1;
}

  previousRed = redValue;
}