project report emf detector -...

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Project Report

EMF DETECTOR

Adarsh Kumar (120260013)

Yashwanth Sandupatla (120260022)

Vishesh Arya (120260001)

Indian Institute of Technology

Bombay

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Abstract

Deflection instruments like voltmeters and ammeters, such as moving coil, the magnetic vane, electrodynamometer, hot wire and electrostatic instruments cannot be read with a high accuracy due to some disturbing influences. One such example is stray EMF in the vicinity of our experimental setup. We’ve made an EMF detector which can detect stray EMF and we can choose suitable location for our experiment accordingly.

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Acknowledgement

The efforts we’ve made in this project would not have been possible without the kind support and help of many individuals. We would like to extend our sincere thanks to all of them. We are highly indebted to Mr. Nitin Pawar and Prof. Pradeep Sarin for their guidance and constant supervision as well as for providing necessary information regarding the project and also for their support in completing the project. We would like to express our gratitude towards our parents and friends for their kind co-operation, encouragement and giving us such attention and time which helped us in completion of this project.

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Contents

1. Introduction and operation Page 5

2. Algorithm Page 6

3. Arduino Code Page 7-15

4. Circuit Diagram Page 16

5. Snapshots—EMF Detector Page 17

6. Problems Faced Page 18

7. Scope Page 19

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INTRODUCTION

Our purpose is to build an EMF detector which can detect stray EMF in our

vicinity so that we can apply that knowledge to carefully choose the

environment for experimental setups concerned with accuracy of deflection

instruments. We’ve used LEDs/7-segment LED display, resistors, solid core wire

(antennae) and Arduino.

Operation of the detector:

Changes in electric fields induce a potential in the antenna wire, which is then

read by the Arduino. A code is written which makes LEDs glow whenever

Arduino gets any reading of stray EMF in the vicinity. The function the 3.3 meg-

ohm resistor is changing the sensitivity of the device. In our charge detector, the

antenna picks up a charge from a nearby object and the 3.3 meg-ohm resistor

controls how quickly the charge will dissipate to ground, and therefore how

sensitive the circuit is to external E-fields.

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ALGORITHM

Important Variables:

1. Sense limit - Variable to control Sensitivity

2. NUMREADINGS - Variable to increase data smoothing

3. val - stores the analog input

4. readings[NUMREADINGS] - Array to store readings for smoothing

Steps:

1. First all the elements are initialized to 0 in the readings array. 2. Then analog input from probe pin 5 is is stored in val. 3. val is the constrained within the sense limit and then mapped to 1-1023 4. All the readings in the loop till the 15th loop is stored in the variable

Total using the readings array.After the 15th loop the Total variable is cleared of the previous readings.

5. The value Total is averaged over the 15 loops and stored in the variable average.

6. The higher the average more number of LED’s will glow.

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ARDUINO CODE

//EMF Detector

//Project by

//Vishesh Arya - 120260001

//Yashwanth Sandupatla - 120260022

//Adarsh Kumar - 120260013

#define NUMREADINGS 15 // Variable to increase data smoothing

int senseLimit = 15; // Variable to decrease sensitivity (up to 1023 max)

int probePin = 5; // analog 5

int val = 0; // reading from probePin

int LED1 = 2; // connections

int LED2 = 3; // to the 10 LEDs

int LED3 = 4;

int LED4 = 5;

int LED5 = 6;

int LED6 = 7;

int LED7 = 8;

int LED8 = 9;

int LED9 = 10;

int LED10 = 11;

// variables for smoothing

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int readings[NUMREADINGS]; // the readings from the analog input

int index = 0; // the index of the current reading

int total = 0; // the running total

int average = 0; // final average of the probe reading

//Variable to affect the speed of the updates for numbers. Lower the number the faster it updates.

int updateTime = 40;

void setup() {

pinMode(2, OUTPUT); // specify Display outputs

pinMode(3, OUTPUT);

pinMode(4, OUTPUT);

pinMode(5, OUTPUT);

pinMode(6, OUTPUT);

pinMode(7, OUTPUT);

pinMode(8, OUTPUT);

pinMode(9, OUTPUT);

pinMode(10, OUTPUT);

pinMode(11, OUTPUT);

Serial.begin(9600); // initiate serial connection for debugging/etc

for (int i = 0; i < NUMREADINGS; i++)

readings[i] = 0; // initialize all the readings to 0

intro(); //Runs the intro

}

void loop() {

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LEDlow();

val = analogRead(probePin); // take a reading from the probe

if(val >= 1){ // if the reading isn't zero, proceed

val = constrain(val, 1, senseLimit); // turn any reading higher than the senseLimit value into the senseLimit value

val = map(val, 1, senseLimit, 1, 1023); // remap the constrained value within a 1 to 1023 range

total -= readings[index]; // subtract the last reading

readings[index] = val; // read from the sensor

total += readings[index]; // add the reading to the total

index = index + 1; // advance to the next index

if (index >= NUMREADINGS) // if we're at the end of the array...

index = 0; // ...wrap around to the beginning

average = total / NUMREADINGS; // calculate the average

if (average > 50){ // if the average is over 50

showLED0(); // Show a 0

}

if (average > 150){ // and so on ...


}

if (average > 250){


}

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if (average > 350){


}

if (average > 450){


}

if (average > 550){


}

if (average > 650){


}

if (average > 750){


}

if (average > 850){


}

if (average > 950){


}

Serial.println(average); // use output to aid in calibrating

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delay(updateTime);

}

}

//Show the number 0

void showLED0(){

LEDlow();

digitalWrite(LED1, HIGH);

}

//Show the number 1

void showLED1(){

LEDlow();



}

//Show the number 2

void showLED2(){

LEDlow();




}

//Show the number 3

void showLED3(){

LEDlow();





}

//Show the number 4

void showLED4(){

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LEDlow();






}

//Show the number 5

void showLED5(){

LEDlow();







}

//Show the number 6

void showLED6(){

LEDlow();








}

//Show the number 7

void showLED7(){

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LEDlow();









}

//Show the number 8

void showLED8(){

LEDlow();










}

//Show the number 9

void showLED9(){

LEDlow();





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}

//Resets the display

void LEDlow(){

digitalWrite(LED1, LOW);







}

void intro(){

showLED0();

delay(300);

showLED1();

delay(300);

showLED2();

delay(300);

showLED3();

delay(300);

showLED4();

delay(300);

showLED5();

delay(300);

showLED6();

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delay(300);

showLED7();

delay(300);

showLED8();

delay(300);

showLED9();

delay(300);

LEDlow();

}

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CIRCUIT DIAGRAM

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EMF DETECTOR-FINALLY!!!!

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PROBLEMS FACED

One of the major problems, we faced while making this detector was what

should we use as our antennae.

Another problem was, stray EMF keeps fluctuating rapidly and is very difficult to

observe its nature (i.e high or low). So, to tackle this problem, we used a variable

(average) to average some finite number (here 15) of EMF readings in a loop.

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SCOPE

In the future, we’ll learn how to improve our antennae using a tuning circuit to

detect the presence of stray EMF within a broader range.

project report emf detector -...

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