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

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About: Happy to be able making s*** :)

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

Step 1: Printing All Parts

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

Attachments

Step 2: Electronics

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.

Step 3: Arduino Code

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

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);
 } 
 }

Attachments

Step 4: Set the Time and Date for DS3231 RTC Module

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>

Attachments

Step 5: Screw Mechanism

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.