UCL-Embedded-Automatic-Arduino-Pet-Feeder

Ever been in a situation where you had to leave your beloved pet at home while you’re on vacation, running errands or at work? Or perhaps your petsitter is on a tight schedule, making every minute saved invaluable in ensuring your pet’s well-being.

Well, fret not! Thanks to our recent development from the Automation Engineering department at UCL Odense, we’ve created a guide on how you can create this magnificent machine.

Using the powerful and compact hardware solutions of an Arduino Mega 2560, a Stepper Motor, Stepper Driver and an Ultrasonic Sensor making for one sturdy unit.

Step 1: Hardware Required

– 1x Arduino Mega 2560

– 1x Stepper Motor 12V 28BYJ-48

– 1x Stepper Motor Driver ULN2003

– 1x Ultrasonic sensor HC-SR04

– 1x Clock Module DS1307

– 1x 0.91″ IIC I2C 128×32 SSD1306 SPI OLED Display Module

– 20x Wires M/F & 2x Wire M/M

– 1x Breadboard

– 1x Battery

Step 2: Setup

Power = 5V

Ground = GND

OLED_MOSI = 9

OLED_CLK = 10

OLED_DC = 11

OLED_CS = 12

OLED_RESET = 13

trigPin = 2

echoPin = 3

RTC SDA = SDA 20

RTC SCL = SCL 21

motorPin1Feed = 22

motorPin2Feed = 24

motorPin3Feed = 26

motorPin4Feed = 28

Step 3: 3D Printing… 3D Printing… and Some More 3D Printing

As you might’ve noticed there’s quite the amount of STL-files attached to this Instructable, so it’s quite a necessity for our construction to have a 3D printer at hand.

Although we used all of our designs to create this machine, there are a couple of STL-files you can technically live without;

• “mount-base-pet-feeder.stl” – Depends on how you intend to set up the cabin containing the wiring, Arduino, Stepper Motor and Step Driver
• “left-mount-adjuster-pet-feeder.stl” –
• “right-mount-adjuster-pet-feeder.stl” –
• “left-spacer-mount-adjuster-pet-feeder.stl” –
• “right-spacer-mount-adjuster-pet-feeder.stl” –
• “Bowl-v2.stl” – We won’t hold a grudge if you don’t use our purpose-built bowl.
• “M&M’s.stl” – This was only used for rendering and illustrating our Automatic PetFeeder in Autodesk Fusion 360. **Not to be used as food for your pet. We hold no responsibility in improper usage**

Step 4: Let’s Add Some Code

<p>//Basic Embedded Programming 2. Semester Project UCL</p><p>//TinyRTC I2C module DS1307
#include "Wire.h"
#define DS1307_I2C_ADDRESS 0x68
// Convert normal decimal numbers to binary coded decimal
byte decToBcd(byte val)
{
  return( (val/10*16) + (val%10) );
}
// Convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
  return( (val/16*10) + (val%16) );
}</p><p>#include 
#include 
#include 
#include 
#include 
#include 
RTC_DS1307 RTC;
//#include DS1307 rtc(SDA, SCL);</p><p>//declaring variables for the motor (driver) pins
int motorPin1Feed = 22;
int motorPin2Feed = 24;
int motorPin3Feed = 26;
int motorPin4Feed = 28;</p><p>//if(hour >= 
int petFeedMorning;
int petFeedAfternoon;</p><p>int petFedMorning;
int petFedAfternoon;</p><p>//Declare ultrasonic sensor pins
int trigPin = 2;    // Trigger
int echoPin = 3;    // Echo
long duration, cm, inches;</p><p>// Variables will change:
//Millis()
long previousMillis = 0;        // will store last time LED was updated</p><p>// the follow variables is a long because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long interval = 1000; // interval at which to blink (milliseconds)</p><p>//Disp millis()
//int period = 1000;
unsigned long time_now = 0;</p><p>#define STEPSFeed 64
#define STEPSTop 64  //Number of steps per revolution
#define STEPSBottom 64  //Number of steps per revolution</p><p>//The pin connections need to be 4 pins connected
// to Motor Driver In1, In2, In3, In4 and then the 
// here in the sequence 1-3-2-4 for proper sequencing of 28BYJ48
Stepper small_stepperFeed(STEPSFeed, motorPin1Feed, motorPin3Feed, motorPin2Feed, motorPin4Feed);</p><p>Stepper small_stepperTop(STEPSTop, motorPin1Top, motorPin3Top, motorPin2Top, motorPin4Top);</p><p>int Steps2TakeFeed;
int Steps2TakeTop;</p><p>unsigned long startMillis;  //some global variables available anywhere in the program
unsigned long currentMillis;
const unsigned long period = 1000;  //the value is a number of milliseconds</p><p>#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels</p><p>// Declaration for SSD1306 display connected using software SPI (default case):
#define OLED_MOSI   9
#define OLED_CLK   10
#define OLED_DC    11
#define OLED_CS    12
#define OLED_RESET 13
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT,
  OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);</p><p>// 'Logo 2', 128x32px
static const unsigned char myBitmap [] PROGMEM = {
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbc, 0x3c, 0xc6, 0x1e, 0x0e, 0x07, 0xfc, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbc, 0x3c, 0xc6, 0x3c, 0x0f, 0x07, 0xfc, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xb4, 0x7c, 0xc6, 0x78, 0x1f, 0x07, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbe, 0x7c, 0xc6, 0xf0, 0x1b, 0x87, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbe, 0x7c, 0xc7, 0xe0, 0x1b, 0x87, 0xf8, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xb6, 0x7c, 0xc7, 0xe0, 0x39, 0x87, 0xf8, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xba, 0x5c, 0xc7, 0xf0, 0x31, 0xc7, 0xf8, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbb, 0xdc, 0xc7, 0x70, 0x7f, 0xc7, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbb, 0xdc, 0xc6, 0x38, 0x7f, 0xc7, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbb, 0xdc, 0xc6, 0x1c, 0x60, 0xe7, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xbb, 0x9c, 0xc6, 0x1e, 0xe0, 0xe7, 0xfc, 0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0xb9, 0x9c, 0xc6, 0x0e, 0xe0, 0x67, 0xfc, 0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xe7, 0xfc, 0xe0, 0xc7, 0x0e, 0x73, 0x83, 0x07, 0xe1, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xc7, 0xfc, 0xf0, 0xc7, 0x0e, 0x73, 0x83, 0x0f, 0xf1, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xe7, 0x00, 0xf8, 0xc7, 0x8e, 0x73, 0xc3, 0x1c, 0x39, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xe7, 0x00, 0xf8, 0xc7, 0x8e, 0x73, 0xe3, 0x38, 0x19, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xc7, 0x00, 0xfc, 0xc6, 0xce, 0x73, 0x63, 0x38, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x7f, 0xe7, 0xfc, 0xec, 0xc6, 0xee, 0x73, 0x73, 0x38, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x7f, 0xe7, 0xfc, 0xee, 0xc6, 0x6e, 0x73, 0x33, 0x38, 0xf9, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xc7, 0x00, 0xe6, 0xc6, 0x7e, 0x73, 0x1b, 0x30, 0xf9, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xc7, 0x00, 0xe3, 0xc6, 0x3e, 0x73, 0x1b, 0x38, 0x19, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x60, 0xe7, 0x00, 0xe3, 0xc6, 0x3e, 0x73, 0x0f, 0x38, 0x39, 0xff, 
  0xff, 0xbf, 0xff, 0xff, 0xfc, 0x60, 0xc7, 0xfc, 0xe1, 0xc6, 0x1e, 0x73, 0x0f, 0x1e, 0x79, 0xff, 
  0xff, 0xbf, 0xff, 0xff, 0xfc, 0x60, 0xc7, 0xfc, 0xe1, 0xc6, 0x0e, 0x73, 0x07, 0x0f, 0xf9, 0xff, 
  0xff, 0xbf, 0xff, 0xff, 0xfc, 0x60, 0xe7, 0xfe, 0xe0, 0xc6, 0x0e, 0x73, 0x07, 0x07, 0xc9, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff, 
  0xff, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0xff
};</p><p>void setup() {</p><p>  Wire.begin();
  //Serial Port begin
  Serial.begin(9600);
  // Using this to set the initial time:
  // DS1307 seconds, minutes, hours, day, date, month, year
  // setDS1307time(30,9,19,1,1,4,19);
  // 1 = Sunday
  
  //Define inputs and outputs (Ultrasonic sensor)
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);</p><p>  startMillis = millis();  //initial start time</p><p>  // put your setup code here, to run once:
  small_stepperFeed.setSpeed(200);
  small_stepperTop.setSpeed(200);</p><p>  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }</p><p>  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
  delay(500); // Pause for 2 seconds</p><p>  // Clear the buffer
  display.clearDisplay();</p><p>}</p><p>void loop() {
  
  //Over 35 cm display length, time, day and date
  if(cm >= 45) {
    ultrasonic();
    displayTimeSerial();
    displayTimeDisplay();
    delay(750);
    displayDayDateDisplay();
    delay(750);
    checkTime();
    Serial.print("Morning: ");
    Serial.println(petFeedMorning);
    Serial.print("Afternoon: ");
    Serial.println(petFeedAfternoon);
    }
  //Between 35 cm (under) and 5 cm (over) feed pet, turn motor CW
  //else if(cm <= 20 && hour >= 7 && hour <= 13) {
  if(cm <= 45 && cm >8) {
    ultrasonic();
    stepMotorFeed();
  }
  //Under 5 cm display length, time, day and date
  else if(cm <= 8) {
    ultrasonic();
    displayTimeSerial();
    displayTimeDisplay();
    if(petFedMorning <1) {
      petFedMorning +1;
      Serial.print(petFedMorning);
    }
  }
}</p><p>void setDS1307time(byte second, byte minute, byte hour, byte dayOfWeek, byte
dayOfMonth, byte month, byte year)
{
  // sets time and date data to DS1307
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.write(0); // set next input to start at the seconds register
  Wire.write(decToBcd(second)); // set seconds
  Wire.write(decToBcd(minute)); // set minutes
  Wire.write(decToBcd(hour)); // set hours
  Wire.write(decToBcd(dayOfWeek)); // set day of week (1=Sunday, 7=Saturday)
  Wire.write(decToBcd(dayOfMonth)); // set date (1 to 31)
  Wire.write(decToBcd(month)); // set month
  Wire.write(decToBcd(year)); // set year (0 to 99)
  Wire.endTransmission();
}</p><p>void readDS1307time(byte *second,
byte *minute,
byte *hour,
byte *dayOfWeek,
byte *dayOfMonth,
byte *month,
byte *year)
{
  Wire.beginTransmission(DS1307_I2C_ADDRESS);
  Wire.write(0); // set DS1307 register pointer to 00h
  Wire.endTransmission();
  Wire.requestFrom(DS1307_I2C_ADDRESS, 7);
  // request seven bytes of data from DS1307 starting from register 00h
  *second = bcdToDec(Wire.read() & 0x7f);
  *minute = bcdToDec(Wire.read());
  *hour = bcdToDec(Wire.read() & 0x3f);
  *dayOfWeek = bcdToDec(Wire.read());
  *dayOfMonth = bcdToDec(Wire.read());
  *month = bcdToDec(Wire.read());
  *year = bcdToDec(Wire.read());
}</p><p>void checkTime() {
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
  // retrieve data from DS1307
  readDS1307time(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month,
  &year);
  
  if(hour >= 6 && hour <= 11) {
    petFeedMorning = 1;
  }
  else if (hour >= 5 && hour <= 13) {
    petFeedMorning = 0;
  }
  if(hour >= 17 && hour <= 21) {
    petFeedAfternoon = 1;
  }
  else if(hour <= 16 && hour >= 18) {
    petFeedAfternoon = 0;
  }
  
}</p><p>void displayTimeSerial()
{
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
  // retrieve data from DS1307
  readDS1307time(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month,
  &year);
  //Current function prints this on the serial monitor
  Serial.print(hour, DEC);
  
  // convert the byte variable to a decimal number when displayed
  Serial.print(":");
  if (minute<10)
  {
    Serial.print("0");
  }
  Serial.print(minute, DEC);
  Serial.print(":");
  if (second<10)
  {
    Serial.print("0");
  }</p><p>  //Print seconds on serial monitor
  Serial.print(second, DEC);
  Serial.print(" ");
  //Print numerical day of the month on serial monitor
  Serial.print(dayOfMonth, DEC);
  Serial.print("/");
  //Print month on serial monitor
  Serial.print(month, DEC);
  Serial.print("/");
  //Print year on serial monitor
  Serial.print(year, DEC);
  Serial.print(" Day of week: ");
  //Determine specific day of the week
  switch(dayOfWeek){
  case 1:
    Serial.println("Sunday");
    break;
  case 2:
    Serial.println("Monday");
    break;
  case 3:
    Serial.println("Tuesday");
    break;
  case 4:
    Serial.println("Wednesday");
    break;
  case 5:
    Serial.println("Thursday");
    break;
  case 6:
    Serial.println("Friday");
    break;
  case 7:
    Serial.println("Saturday");
    break;
  }
}</p><p>void displayTimeDisplay()
{
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
  // retrieve data from DS1307
  readDS1307time(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month,
  &year);
  //Current function shows this on the OLED display
  //Display
  //TODO Millis
/*
  currentMillis = millis();  //get the current "time" (actually the number of milliseconds since the program started)
  if (currentMillis - startMillis >= period)  //test whether the period has elapsed
  {
    display.clearDisplay();
    display.display();
    display.setCursor(0,0);
    display.setTextSize(2);             // Draw 2X-scale text
    display.setTextColor(WHITE);
    display.print(cm);
    display.println(" Millis");
    display.display();
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    startMillis = currentMillis;  //IMPORTANT to save the start time of the current LED state.
  }
  */
  
  //Display distance measured from Ultrasonic sensor on OLED
  display.clearDisplay();
  display.display();
  display.setCursor(0,0);
  display.setTextSize(2);             // Draw 2X-scale text
  display.setTextColor(WHITE);
  display.print(cm);
  display.println(" cm");
  
  display.setTextSize(1);             // Draw 2X-scale text
  display.setTextColor(WHITE);
  display.println();
  //Display hours on OLED
  display.print(hour, DEC);
  
  //Converting the byte variable to a decimal number when displayed
  display.print(":");
  if (minute<10)
  {
    display.print("0");
  }
  //Display minutes on OLED
  display.print(minute, DEC);
  display.print(":");
  if (second<10)
  {
    display.print("0");
  }
  
  //Display seconds on OLED
  display.print(second, DEC);
  display.print(" ");</p><p>  //Between 35 cm (under) and 5 cm (over) feed pet, turn motor CW
  //else if(cm <= 20 && hour >= 7 && hour <= 13) {
  if(cm <= 35 && cm >5) {
    display.setCursor(85,25);
    display.setTextSize(1);             // Draw 2X-scale text
    display.setTextColor(WHITE);
    display.print("FEEDING");
  }
  //Under 5 cm display length, time, day and date
  else if(cm <= 5) {
    display.setCursor(85,25);
    display.setTextSize(1);             // Draw 2X-scale text
    display.setTextColor(WHITE);
    display.print("DONE");
  }
  
  display.display();
  //TODO Millis
  //delay(1000);
}</p><p>void displayDayDateDisplay()
{
  byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
  //Retrieving data from DS1307
  readDS1307time(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month,
  &year);
  //Sending it to the OLED display
  //Display
  //TODO Millis
  //Day
  display.clearDisplay();
  display.setCursor(0,0);
  display.setTextSize(1);             // Draw 2X-scale text
  display.setTextColor(WHITE);
  display.println();</p><p>  //Determine specific day of the week
  switch(dayOfWeek){
  case 1:
    display.println("Sunday");
    //display.println();
    break;
  case 2:
    display.println("Monday");
    break;
  case 3:
    display.println("Tuesday");
    break;
  case 4:
    display.println("Wednesday");
    break;
  case 5:
    display.println("Thursday");
    break;
  case 6:
    display.println("Friday");
    break;
  case 7:
    display.println("Saturday");
    break;
  }
  //Date
  display.setTextSize(2);             // Draw 2X-scale text
  display.setTextColor(WHITE);
  display.print(dayOfMonth, DEC);
  display.print("/");
  display.print(month, DEC);
  display.print("/");
  display.print(year, DEC);
  display.println(" ");
  
  display.display();
  //TODO Millis
  //delay(500);
}</p><p>void ultrasonicTimeout() {
  // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  /*
  //Without Millis
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  */</p><p>  currentMillis = millis();  //get the current "time" (actually the number of milliseconds since the program started)
  if (currentMillis - startMillis >= period)  //test whether the period has elapsed
  {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    startMillis = currentMillis;  //IMPORTANT to save the start time of the current LED state.
  }
 
  // Read the signal from the sensor: a HIGH pulse whose
  // duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
 
  // Convert the time into a distance
  cm = (duration/2) / 29.1;     // Divide by 29.1 or multiply by 0.0343
  inches = (duration/2) / 74;   // Divide by 74 or multiply by 0.0135
  
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();</p><p>  //delay(200);
}</p><p>void ultrasonic() {
  // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  /*
  //Without Millis
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  */
  
  currentMillis = millis();  //get the current "time" (actually the number of milliseconds since the program started)
  if (currentMillis - startMillis >= period)  //test whether the period has elapsed
  {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(5);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    startMillis = currentMillis;  //IMPORTANT to save the start time of the current LED state.
  }
 
  // Read the signal from the sensor: a HIGH pulse whose
  // duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);
 
  // Convert the time into a distance
  cm = (duration/2) / 29.1;     // Divide by 29.1 or multiply by 0.0343
  inches = (duration/2) / 74;   // Divide by 74 or multiply by 0.0135
  
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();
}</p><p>void stepMotorFeed() {
/*
  currentMillis = millis();  //get the current "time" (actually the number of milliseconds since the program started)
  if (currentMillis - startMillis >= period)  //test whether the period has elapsed
  {
    //function to turn stepper motor 32 steps left
    small_stepperFeed.setSpeed(300);  // 200 as max speed?
    //ultrasonic();
    Steps2TakeFeed  =   -3200;  // Rotate CW
    //ultrasonic();
    small_stepperFeed.step(Steps2TakeFeed);
    startMillis = currentMillis;  //IMPORTANT to save the start time of the current LED state.
  }
  */
  
  //function to turn stepper motor 32 steps left
  small_stepperFeed.setSpeed(300);  // 200 as max speed?
  //ultrasonic();
  Steps2TakeFeed  =   -520;  // Rotate CW
  //ultrasonic();
  small_stepperFeed.step(Steps2TakeFeed);
}</p><p>void testdrawlogo() {
  display.clearDisplay();</p><p>  display.drawBitmap(
    (display.width()  - SCREEN_WIDTH ),
    (display.height() - SCREEN_HEIGHT),
    myBitmap, SCREEN_WIDTH, SCREEN_HEIGHT, 1);
  display.display();
  // Invert and restore display, pausing in-between
  display.invertDisplay(true);
  delay(1000);
  display.invertDisplay(false);
  delay(8000);
}</p>

Source: UCL-Embedded-Automatic-Arduino-Pet-Feeder