Automatic Arduino Pet Feeder - 3D Printed (With Stepper Motor)

Hi guys,

I made an automatic 3D Printed Pet Feeder (or just dispenser, but I use it to feed my dog). I 3D modelled all that project. U can print it by yourself. All parts are down there.

Basically how it works, is u type in two Feeding Times, for example 8:30 and 17:30, then when time is right stepper motor enables and feeds your little pet.

Electric Components:

• Stepper Motor NEMA17 - 42HB34F08AB
• Stepper Motor Driver A4988
• Arduino UNO
• Arduino Keypad 4x4
• RTC DS3231 Clock
• LCD Display 16x2
• Step Down Module (I used LM2596S DC/DC) 12V to 5V
• 12V Power Supply
• a lot of wires

Printing all the parts took me about 5 days. To assemble everything together I used 3mm bolts (m3) and 3mm nuts.

Wire everything like in the circuit. If your LCD screen is too dark or too bright try different values of resistors or play with the voltage regulator.

Arduino Code includes additional libraries: DS3231 RTC, Arduino Keypad 4x4

• Keypad library
• DS3231 library

When you press 'A' - Program asks for first feed time and waits untill you type in HH:MM:SS

When you press 'B' - Program asks for second feed time and waits untill you type in HH:MM:SS

When you press 'C' - Stepper Motor runs for one cycle (one feed)

When you press 'D' - LCD displays current Date

LCD displays normally current Time and hour and minutes of first and second feed time.

All functions are described in code:

#include <DS3231.h>
#include <LiquidCrystal.h>
#include <Keypad.h>


const byte ROWS = 4;
const byte COLS = 4;
const int stepPin = 10;
const int dirPin = A3;

char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = { 2, 3, 4, 5 };
byte colPins[COLS] = { 6, 7, 8, 9 };

Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
DS3231 rtc(A4, A5);

LiquidCrystal lcd(A0, A1, A2, 11, 12, 13); // (rs, enable, d4, d5, d6, d7)

int feed_time = 2000;    //define how fast stepper motor works
int feed_length = 600;   //define how much steps should your motor do (mine does 200 for full spin)

String feed1;
String feed2;
char key[8];
int j = 0;
char button;


 void setup() {
  
  rtc.begin();
  lcd.begin(16,2);
  Serial.begin(9600);
  pinMode(A0, OUTPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(stepPin,OUTPUT); 
  pinMode(dirPin,OUTPUT);
}
 
 void loop() {

 lcd.setCursor(0,0);
 lcd.print("Time: ");
 lcd.print(rtc.getTimeStr());
 lcd.setCursor(0,1);
      //lcd.print("Date: ");               //Date to display
      //lcd.print(rtc.getDateStr());
 lcd.print("1)");
 lcd.print(feed1);
 lcd.setCursor(7,1);
 lcd.print(" 2)");
 lcd.print(feed2);
 lcd.setCursor(15,1);
 lcd.print(" ");
  
 button = keypad.getKey();
 
 if(button == 'A'){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("HH:MM:SS 1st");
  delay(500);
  j = 0;
  lcd.setCursor(j,1);
  key[0] = keypad.waitForKey();
  lcd.print(key[0]);j++;
  lcd.setCursor(j,1);
  key[1] = keypad.waitForKey();
  lcd.print(key[1]);j++;
  lcd.setCursor(j,1);
  key[2] = ':';
  lcd.print(key[2]);j++;
  lcd.setCursor(j,1);
  key[3] = keypad.waitForKey();
  lcd.print(key[3]);j++;
  lcd.setCursor(j,1);
  key[4] = keypad.waitForKey();
  lcd.print(key[4]);j++;
  lcd.setCursor(j,1);
  key[5] = ':';
  lcd.print(key[5]);j++;
  lcd.setCursor(j,1);
  key[6] = keypad.waitForKey();
  lcd.print(key[6]);j++;
  lcd.setCursor(j,1);
  key[7] = keypad.waitForKey();
  lcd.print(key[7]);
  key[8] = '\0';
  feed1 = String(key);
  delay(1000);
  lcd.clear(); 
 }

 if(button == 'B'){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("HH:MM:SS 2nd");
  delay(500);
  j = 0;
  lcd.setCursor(j,1);
  key[0] = keypad.waitForKey();
  lcd.print(key[0]);j++;
  lcd.setCursor(j,1);
  key[1] = keypad.waitForKey();
  lcd.print(key[1]);j++;
  lcd.setCursor(j,1);
  key[2] = ':';
  lcd.print(key[2]);j++;
  lcd.setCursor(j,1);
  key[3] = keypad.waitForKey();
  lcd.print(key[3]);j++;
  lcd.setCursor(j,1);
  key[4] = keypad.waitForKey();
  lcd.print(key[4]);j++;
  lcd.setCursor(j,1);
  key[5] = ':';
  lcd.print(key[5]);j++;
  lcd.setCursor(j,1);
  key[6] = keypad.waitForKey();
  lcd.print(key[6]);j++;
  lcd.setCursor(j,1);
  key[7] = keypad.waitForKey();
  lcd.print(key[7]);
  key[8] = '\0';
  feed2 = String(key);
  delay(1000);
  lcd.clear(); 
 }
 if(button == 'D'){
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Time: ");
  lcd.print(rtc.getTimeStr());
  lcd.setCursor(0,1);
  lcd.print("Date: ");               //Date to display
  lcd.print(rtc.getDateStr());
  delay(5000);
  lcd.clear();
 }
 if(button == 'C'){
 digitalWrite(dirPin,HIGH);        // Enables the motor to move in a particular direction
  
  for(int x = 0; x < feed_length; x++) {     // Makes 200 pulses for making one full cycle rotation
    digitalWrite(stepPin,HIGH); 
    delayMicroseconds(feed_time); 
    digitalWrite(stepPin,LOW); 
    delayMicroseconds(feed_time); 
  }
  delay(1000);
 } 
 if (feed1==rtc.getTimeStr())
 {  
   digitalWrite(dirPin,HIGH);        // Enables the motor to move in a particular direction
  
  for(int x = 0; x < feed_length; x++) {     // Makes 200 pulses for making one full cycle rotation
    digitalWrite(stepPin,HIGH); 
    delayMicroseconds(feed_time); 
    digitalWrite(stepPin,LOW); 
    delayMicroseconds(feed_time); 
  }
  delay(1000);
 } 
 if (feed2==rtc.getTimeStr())
 { 
  digitalWrite(dirPin,HIGH);        // Enables the motor to move in a particular direction
  
  for(int x = 0; x < feed_length; x++) {     // Makes 200 pulses for making one full cycle rotation
    digitalWrite(stepPin,HIGH); 
    delayMicroseconds(feed_time); 
    digitalWrite(stepPin,LOW); 
    delayMicroseconds(feed_time); 
  }
  delay(1000);
 } 
 } 

Here is code for setting the Time and Date in your DS3231 (it includes library like in the previous step) - DS3231 library

The DS3231 SDA ---> A4 in Arduino

The DS3231 SCL ---> A5 in Arduino

When u write that code into arduino, u have to open the serial monitor (115200) and just check if your time and date match.

#include <DS3231.h>

// Init the DS3231 using the hardware interface
DS3231  rtc(A4, A5);

void setup()
{
  // Setup Serial connection
  Serial.begin(115200);
  
  // Initialize the rtc object
  rtc.begin();
  
  // Write your current time and date to this following lines
  rtc.setDOW(MONDAY);     // Set Day-of-Week to Monday
  rtc.setTime(12, 0, 0);     // Set the time to 12:00:00 (24hr format)
  rtc.setDate(01, 01, 2014);   // Set the date to January 1st, 2014
}

void loop()
{
  // Send Day-of-Week
  Serial.print(rtc.getDOWStr());
  Serial.print(" ");
  
  // Send date
  Serial.print(rtc.getDateStr());
  Serial.print(" -- ");

  // Send time
  Serial.println(rtc.getTimeStr());
  
  // Wait one second before repeating :)
  delay (1000);
}<br>

U just put a nut in hole and screw it with all your force. It keeps screw and motor shaft together and tight.

3D printing that screw was a little harder than I thought. I'm using Ender 3 and I couldn't print it standing (vertically). Model was just collapsing. The only way, that was working for me, was printing it horizontally with support blocks like on photos.