Published January 31, 2024 © Apache-2.0

Automatic Garbage Opener with Ultrasonic Sensor

Using a stepper motor, some string, an ultrasonic sensor, an Arduino, and a garbage bin, you can build your own automatic garbage opener!

IntermediateFull instructions provided1 hour185

Automatic Garbage Opener with Ultrasonic Sensor

Things used in this project

Hardware components

Digilent Stepper Motor

Texas Instruments BOOSTXL-ULN2003 ULN2003A Dual Stepper Motor BoosterPack

Ultrasonic Sensor - HC-SR04 (Generic)

A spool of thread

Arduino Mega 2560

Software apps and online services

Arduino IDE

Story

Introduction

Have you ever seen a bin of garbage and felt a bit disgusted by it, but you still had to throw your garbage away, forcing you to open it? Well, no longer with this project! In this project, you'll learn how to build an automatic garbage opener.

Circuit

Connect your stepper motor to the ULN2003 module. Then, connect pins IN1 - IN4 to the Arduino pins 8 - 11, respectively. Connect the + pin on the ULN2003 to the 5V pin on the Arduino, and the - pin on the ULN2003 to the GND pin on the Arduino. This is the circuit for the stepper motor.

Connect the Trig and Echo pins on the Ultrasonic Sensor to pins 4 and 3 on the Arduino, respectively. Connect the VCC pin to another 5V pin on the Arduino, and connect GND to another GND pin on the Arduino.

With that, the circuit is all ready to go!

Code

The code is available at the bottom of the page. Upload the sketch to the Arduino.

Build

Tape or glue your components and circuit to some kind of platform, I used a square of cardboard. Attach the platform to a wall. Attach a spool of thread to the shaft of the stepper motor with hot glue, so that the spool rotates with the motor. Take your garbage bin and place it near the wall. Unravel your thread and tape/glue/fasten the end of the thread to the back of the garbage bin lid. Plug the Arduino into a socket and wave your hand in front of the sensor, and the motor will turn the spool, reeling in the thread and pulling up the lid automatically. You may need to experiment with different angles and lengths of thread.

FinalResult

You should end up with something like this!

Code for the project

//Including Libraries
#include <Stepper.h>
#include "SR04.h"
//Setting pins
#define TRIG_PIN 4
#define ECHO_PIN 3
//Creates an instance of our ultrasonic sensor
SR04 sr04 = SR04(ECHO_PIN,TRIG_PIN);
//A variable to store the sensor's value
long a;

// Defines the number of steps per rotation
const int stepsPerRevolution = 2038;

// Creates an instance of stepper class
// Pins entered in sequence IN1-IN3-IN2-IN4 for proper step sequence
Stepper myStepper = Stepper(stepsPerRevolution, 8, 10, 9, 11);

void setup() {
    // Nothing to do (Stepper Library sets pins as outputs)
    Serial.begin(9600);
    myStepper.setSpeed(15);
}

void loop() {
  //Store the distance returned by the sensor
  a=sr04.Distance();
  //If the distance is less than 40
  if(a <= 40) 
  { 
    //Turn for 3 whole revolutions
    myStepper.step(-stepsPerRevolution * 3);
    //Print a message
    Serial.println("Opened");
    //Wait some time
    delay(6000);
    //Turn in the opposite direction.
    myStepper.step(stepsPerRevolution * 3); 
    Serial.println("Closed");
  }
 

}