Infusion Pump

Harvey Kyllonen

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Features

• Pump runs for 5 seconds, and is off for 20 seconds, this process repeats
• The user is able to activate the pump using a push button
• Green LED is ON when pump is active
• Red LED is ON when pump is IDLE
• Temperature is taken using a Thermistor
• Buzzer activates and pump turns OFF if the patients temp exceeds 80 degrees fahrenheit
• LCD screen displays patients temperature. It also displays a warning when the temperature exceeds 80 degrees fahrenheit

Tech

Infusion Pump Components:

• Arduino Uno - Arduino Uno microcontroller
• Arduino IDE - Arduino IDE, edit and upload your code to the microcontroller
• LEDs - Two LEDs, one red one green
• Jumper Cables - Multiple male to male jumper cables
• Push button - a pushbutton for user input.
• DC Motor - A direct current motor, this is necessary for the pump
• 330 Ohm Resistors - Used for LEDs and the push button
• MOSFET Transistor - This is connected to our motor
• Thermistor - takes the patient's temperature
• 10k Ohm Resistor - Used for the Thermistor
• Buzzer - Plays a high frequency tone notifying nearby operators
• Liquid-crystal display (LCD) - Displays temperature readings and warnings

Installation

The following diagram was made with Fritzing:

Software

Line 12

Import and define the LCD screen

Initializing integer pin values and associated variables

#include <LiquidCrystal.h>

LiquidCrystal lcd(7,8,9,10,11,12,13);

int greenLED = 2; // green LED set to pin 2
int redLED = 4; // red LED set to pin 4
int button = 3; // button set to pin 3
int motor = 5; // motor set to pin 6
int buttonInput = 0; // buttonInput set to 0 meaning not pressed

int buzzer = 6; // buzzer set to pin 6
int thermPin = A0; // thermal input A0 pin
int thermValue = 0; // thermal value initialized to 0

static bool pressedStatus;

Line 32

Setup function

Setting pins to proper INPUT or OUTPUT value

Starting up the LCD display

void setup() {
  pinMode(greenLED,OUTPUT);
  pinMode(redLED,OUTPUT);
  pinMode(button,INPUT);
  pinMode(thermPin,INPUT);
  pinMode(buzzer,OUTPUT);
  Serial.begin(9600);
  Serial.println("Program Reset"); 
  
  lcd.begin(20,4);               // name.begin(cols,rows) is the code that gives the dimensions of the LCD 
  lcd.clear();		    //Has the LCD blank the screen
  lcd.setCursor(0,1);	  //set cursor to column 0, row 2
  lcd.print("Program Reset");
}

Line 51

Loop the pumpMain() function

Clear the display and print the patient's temp to it.

void loop() {
  pumpMain();

  lcd.clear(); // clear screen
  lcd.setCursor(0,1);	  //set cursor to column 0, row 2
  lcd.print("Temp:" + String(thermOutput())); // print temp to screen
  Serial.print("Temp:" + String(thermOutput())); // print temp to serial monitor
}

Line 68

The pumpMain() function

Turns the pump on and off using the appropriate functions

Delay is in milliseconds

If the temperature exceeds 80 degrees fahrenheit, play the buzzer, display a warning, and disable the pump

void pumpMain(){
  if(isPressed()==true){
    pumpOn();
    delay(5000); // wait for 5 seconds with motor ON
    pumpOff();

    if(thermOutput()>=80){
      pressedStatus = false; // set pressed to false
      lcd.clear(); // clear screen
      lcd.setCursor(0,1);	  //set cursor to column 0, row 2
      lcd.print("EMERGENCY SHUTDOWN: TEMP EXCEEDED 80"); // print to screen
      Serial.println("EMERGENCY SHUTDOWN: TEMP EXCEEDED 80"); // print warning to user
      tone(buzzer,1000,1000); // play buzzer tone for 1 second
      pumpOff(); // disable pump
    }

    delay(20000); // Wait 20 seconds
    lcd.clear(); // clear screen
  }
  else{
    pumpOff(); // disable pump
  }
}

Line 98

Turns the motor ON, as well as the green LED. The red LED is turned OFF

void pumpOn(){
  Serial.println("Motor on");
  analogWrite(motor,255); // turn motor to max speed
  digitalWrite(greenLED,HIGH); // green LED ON
  digitalWrite(redLED,LOW);// red LED OFF
}

Line 111

Turns the motor OFF, and the green LED OFF The red LED is set to ON

void pumpOff(){
  Serial.println("Motor off");
  analogWrite(motor,0); // Turn motor OFF
  digitalWrite(greenLED,LOW); // turn green LED OFF
  digitalWrite(redLED,HIGH); // turn red LED ON
}

Line 125

Check if the button is pressed This function is of type bool, it will return a bool (True/False)

bool isPressed(){
  static bool pressedStatus;
  buttonInput = digitalRead(button); //. read button input
  
  if(buttonInput == 1 && pressedStatus == true){ // if button pressed and its already been pressed before
    Serial.println("pressed to false");
    pressedStatus = false; // set pressed to false
    return pressedStatus;
  }
  else if(buttonInput == 1 && pressedStatus == false){ // If button pressed
    Serial.println("pressed to true");
    pressedStatus = true; // set pressed to true
    return pressedStatus;
  }
  return pressedStatus;
}

Line 148

This function reads the temperature value from the thermistor, and converts the temp into fahrenheit.

This function returns a float which is the temp reading in fahrenheit

float thermOutput(){
  thermValue=analogRead(thermPin);

  int R25 = 10000; //Ohms
	float a1 = 3.354016E-3;
	float b1 = 2.56985E-4;
	float c1 = 2.620131E-6;
	float d1 = 6.383091E-8;

  float voltage = float(thermValue)*(5000.0/1024.0); //units are milivolts
  float Rdivider = 10000; //Resistance in Ohms of the other resistor.
  float Rtherm = Rdivider*((5000.0/voltage) -1); //Voltage divider equation
	
  //Thermistor resistance-to-temperature conversion equation (from datasheet)
	float Tkelvin = 1/(a1 + b1*log(Rtherm/R25) \
		+ c1*log(Rtherm/R25)*log(Rtherm/R25) \
		+ d1*log(Rtherm/R25)*log(Rtherm/R25)*log(Rtherm/R25));

  //Temperature conversions
	float Tcelsius = Tkelvin - 273.15;
	float Tfahren = (Tcelsius*(9.0/5.0))+32.0;

  return Tfahren; // return fahrenheit
}