Introduction: Automated Waste Detector


Symbiosis School For Liberal Arts, Pune

Sana Banu - 17060321088 Juhi Shah -17060321041 Manavi Pandey - 18060321070


Garbage has become one of the most serious global issues in today's times. According to an estimation by a report published in the Nature journal, by the end of this century (2100), garbage production will reach a level of 11 million tonnes per day. That would be 3 times the rate at which garbage was produces in 2010, when the report was published. Increase in the quantity of garbage is not as much of a problem as is leaving garbage open and untreated. Even if the global production rate of garbage touches the sky, it will not pose a threat if there are efficient systems to 1) Dispose 2) Treat and 3) Re-use garbage wisely. Unfortunately, it is too late now to take individual steps to tackle a problem so globally wide. This gave us three the idea of creating a mechanised method to either dispose garbage efficiently or treat garbage effectively. This idea was the starting point of our journey. We began with gathering ideas to tackle this problem. A few of the ideas we originally arrived at have been described below:

1) Plastic shredder

One way of treating plastic, a waste that takes numerous years to disintegrate, was shredding it and re-using it. Therefore we looked at the following two videos:


Each of these two videos has an audio-visual representation of how to make a plastic shredder. We thought of making a plastic shredder with the aim of making the collection process of plastic easier. Now, the question arises how will the collection of plastic become easier through a plastic shredder? Plastic garbage takes up a lot of volume. A plastic shredder will help shred the plastic into smaller pieces. Therefore, the volume of the total plastic collected would reduce and help gather and dispose off more plastic.

The problem with this was that if installed at SSLA, at a college level, then it would be difficult to inform students which sub-type of plastic to shred and which to avoid. Because even under the broad category of plastics, there exist multiple sub-types, which require different treatment based on their properties.

2) Smart Bin

The next solution to tackle the problem of waste management was to create a smart bin. The smart bin we envisioned would have sensors that would automatically detect what type of waste a user threw into it. Next, it would use the data of the type of waste and dispose off the respective waste into the specific type of dustbin that it would be meant for. Since these solutions were for a basic prototype we decided to stick to the most basic version of smart bin that we could find. We found the below mentioned video :


The video shown above demonstrates the school project of two children. They have made a automated waste segregator. The machine shown in the video segregates wet and dry waste into two separate compartments using an arduino and flap mechanism.

3) Using melted plastic as ink for 3D printing

What better way to re-cycle plastic than turning it into something new. Therefore, we found a video that displayed a machine which melted plastic and was connected to 3D printing machine. The video has been attached below:

The video displays the negative effects of plastic and then a demo of how one can put in plastic into the melter part of the machine. Then feed in the design of the model into the 3D printer. The machine would then use the melted plastic as ink for the 3D printing and create a 3D model of the design fed into it.

The problem with this was that we were looking at creating a basic prototype over 2 months, approx. 3 days a week, 3 hours daily. This time was not sufficient to complete this project. As well as it was not very useful from a utilitarian perspective. Not everyone can afford a 3D printer and obviously the plastic melting machine would also be mid-range priced.

Step 1:


The inclusion of other types of waste in dustbins causes several problems, all stemming from the fact that contamination reduces the quality of recycled paper and plastic products. We as a group of three observed that there are many people who do not care about the type of dustbin, they are throwing their product. For example, A person would throw a wet can in a dry waste dustbin and vice versa. So the problem we identified was waste being put in the wrong dustbin and people not realising that the dustbin was full. The idea of a waste segregator began when we saw the the problem of improper garbage disposal. Improper garbage disposal leads to breeding of insects, release of hazardous gases, difficulty and health hazards for garbage collectors and a chain of further problems. Therefore, we thought that if we cannot manipulate people into doing what is right, we can manipulate the machine to do what is right.
SOLUTION To prevent this, we have chosen to make a waste segregator which would identify the type of waste put and eventually on its own with our mechanism put it in the right dustbin which would reduce manpower costs and wrong waste going into the dustbin, increasing recycling of paper and plastic products becoming easier. After intensive research on the internet we found out that many others do possess ideas similar to ours and have tried creating dustbins that detect different types of waste and further segregate them into the right category. We decided to stick to detection of different types of waste as part of this project. We have tried to create a mechanism wherein the dustbin first detects that I have something in me, next whether it is wet or dry, and next if it is metal or non-metal waste. We decided to make a IR Sensor, Metal Detector and Moisturizer Detector. We decided to make an IR Sensor to help people identify the dustbin was full by showing a light if it was full. Secondly we decided to make a Metal Detector to prevent people from putting a metal waste in the wrong dustbin, if they would there would be a buzzing sound made and light shown through which they would understand that it wasn’t the right dustbin. Lastly, we decided to make a Moisturizer Detector to detect the wet and dry waste so that if a person puts the wet waste in a dry dustbin there would be light shown which would indicate that the waste was put in the wrong one.

Step 2: Planning


We had initially planned to make a waste segregator that can identify the following waste types - Wet waste, Metal, Plastic, Paper and other dry waste. We had made a design of a detection machine that will make use of arduino to detect its type. After the detection, we had segregation five structures that would collect the appropriate waste. These structures can be removed from the machine like a dustbin manually to recycle or for organic composting and others to be used reused. The structure was designed as such that primarily the waste placed in the e-dustbin will be detected and once it is detected, it will pass through a vertical tunnel or dustin where the first detection of whether it is metal or non-metal takes place. If the waste is detected to be metal, then it will let the waste pass through the end of tunnel to have it segregated in the metal dustin, if the waste is detected to be non-metal then it will pass to the next detection that whether it is dry waste or wet waste, if it detects as wet waste, then it gets segregated to the wet dustbin, if not it passes to the final detection that whether the dry waste is either plastic or paper or neither.Once detected, the waste will be segregated to its following dustbin. Later once these dustbin structures are full, it gives a signal to be removed from the e-dustbin.

Step 3: Practical Making


We had difficulty in figuring out the detection method for paper and plastic. Due to which we ended up making the same model but with detection of wet, dry and metal waste. The presence of the object in the beginning of the detection and whether the dustbin structure is full is detected using IR sensors; Metal and non-metal waste is detected using metal detector and finally, wet and dry waste is detected using moisture sensor. Both the metal and IR sensor requires arduino whereas the moisture sensor can function independent of arduino.

Purpose of each sensor.

IR Sensor

IR Sensor is connected to the dustbin as it would be used to detect the level of dustbin where dustbin is full or empty. It would help us detect when the garbage container has reached its maximum capacity.

Metal Detector

Metal Detector is used to sense weather the garbage thrown is a metal type material or not. If it is a metal material like a bunch of keys it would detect and as per our mechanism, we would hear a beeping sound.

Moisture Sensor

The moisture sensor is used to help identify if the garbage is wet or dry. Incase the garbage is wet like a half-filled juice glass the dustbin would show a light that would help us realize that there is a wet object in the garbage.




Step 4: Mechanism 1 : Detecting Object Using IR Sensor

Mechanisms : Detecting the object using IR Sensor

Things required

  • IR Sensor
  • LED
  • 330 ohm resistor
  • Jumping wires

Block diagram [for IR]

Code for IR - (Copy-Paste)

int LED = 13; // Use the onboard Uno LED int obstaclePin = 7; // This is our input pin int hasObstacle = HIGH; // HIGH MEANS NO OBSTACLE void setup() { pinMode(LED, OUTPUT); pinMode(obstaclePin, INPUT); Serial.begin(9600); } void loop() { hasObstacle = digitalRead(obstaclePin); //Reads the output of the obstacle sensor from the 7th PIN of the Digital section of the arduino if (hasObstacle == LOW) //LOW means something is ahead, so illuminates the 13th Port connected LED { Serial.println("Stop something is ahead!!"); digitalWrite(LED, HIGH);//Illuminates the 13th Port LED } else { Serial.println("Path is clear"); digitalWrite(LED, LOW); } delay(200); }


  • Connect the LED and resistor on a breadboard
  • Connect the jumper wires from the IR sensor to arduino with reference to the block diagram
  • Copy and Paste the code given above in the arduino program
  • Upload and execute it.


Step 5: Mechanism 2: Detection of Metal and Non-metal Waste

Mechanism: Detection of metal and non metal using metal detector

Things required

  • Coil 10nF capacitor
  • Buzzer 1k resistor
  • 330 ohm resistor
  • LED 1N4148 diode
  • Connecting jumper wire 9v
  • Battery

Circuit Diagram:

We have used an Arduino Nano for controlling whole this Metal Detector Project. A LED and Buzzer are used as metal detection indicator. A Coil and capacitor is used for detection of metals. A signal diode is also used for reduce the voltage. a resistor for limiting the current to the Arduino pin.

Block diagram


#define capPin A5 #define buz 9 #define pulsePin A4 #define led 10 long sumExpect=0; //running sum of 64 sums long ignor=0; //number of ignored sums long diff=0; //difference between sum and avgsum long pTime=0; long buzPeriod=0; void setup() { Serial.begin(9600); pinMode(pulsePin, OUTPUT); digitalWrite(pulsePin, LOW); pinMode(capPin, INPUT); pinMode(buz, OUTPUT); digitalWrite(buz, LOW); pinMode(led, OUTPUT); } void loop() { int minval=1023; int maxval=0; long unsigned int sum=0; for (int i=0; i<256; i++) { //reset the capacitor pinMode(capPin,OUTPUT); digitalWrite(capPin,LOW); delayMicroseconds(20); pinMode(capPin,INPUT); applyPulses(); //read the charge of capacitor int val = analogRead(capPin); //takes 13x8=104 microseconds minval = min(val,minval); maxval = max(val,maxval); sum+=val; long unsigned int cTime=millis(); char buzState=0; if (cTime 0) buzState=1; else if(diff<0) buzState=2; } if (cTime>pTime+buzPeriod) { if (diff>0) buzState=1; else if (diff<0) buzState=2; pTime=cTime; } if (buzPeriod>300) buzState=0; if (buzState==0) { digitalWrite(led, LOW); noTone(buz); } else if (buzState==1) { tone(buz,2000); digitalWrite(led, HIGH); } else if (buzState==2) { tone(buz,500); digitalWrite(led, HIGH); } } //subtract minimum and maximum value to remove spikes sum-=minval; sum-=maxval; if (sumExpect==0) sumExpect=sum<<6; //set sumExpect to expected value long int avgsum=(sumExpect+32)>>6; diff=sum-avgsum; if (abs(diff)>10) { sumExpect=sumExpect+sum-avgsum; ignor=0; } else ignor++; if (ignor>64) { sumExpect=sum<<6; ignor=0; } if (diff==0) buzPeriod=1000000; else buzPeriod=avgsum/(2*abs(diff)); } void applyPulses() { for (int i=0;i<25;i++) { digitalWrite(pulsePin,HIGH); //take 3.5 uS delayMicroseconds(5); digitalWrite(pulsePin,LOW); //take 3.5 uS delayMicroseconds(5); } }


  • Connect the LED, resistors, diode, battery and buzzer on the breadboard
  • Connect the jumper wire between arduino and breadboard
  • Here in this circuit, we have used a coil having around 20 turns or winding with a 10cm diameter.
  • We have used an empty tape roll and wind the wire around it to make the coil.
  • Connect these coil to the breadboard

Working Concept: Whenever some current passes through the coil, it generates a magnetic field around it. And the change in the magnetic field generates an electric field. Now according to Faraday's law, because of this Electric field, a voltage develops across the coil which opposes the change in magnetic field and that’s how Coil develops the Inductance, means the generated voltage opposes the increase in the current. When any metal comes near to the coil then coil changes its inductance. This change in inductance depends upon the metal type. It's decreases for non-magnetic metal and increases for ferromagnetic materials like iron.


Step 6: Mechanism 3: Moisture Sensor

Detection of wet and dry waste using water sensor

Things required

  • Led 330 ohm
  • resistor Water sensor
  • 3 pin Transistor

Circuit diagram

Working -

Follow the circuit diagram and hook up the components on the breadboard as shown in the image given above Connect the jumping wire with reference to the image below

Code for Copy-Paste

#define Grove_Water_Sensor 8 // Attach Water sensor to Arduino Digital Pin 8 #define LED 9 // Attach an LED to Digital Pin 9 (or use onboard LED)

void setup() { pinMode(Grove_Water_Sensor, INPUT); // The Water Sensor is an Input pinMode(LED, OUTPUT); // The LED is an Output }

void loop() { /* The water sensor will switch LOW when water is detected. Get the Arduino to illuminate the LED and activate the buzzer when water is detected, and switch both off when no water is present */ if( digitalRead(Grove_Water_Sensor) == LOW) { digitalWrite(LED,HIGH); }else { digitalWrite(LED,LOW); } }