Attiny 45 EMF Sensor

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About: I like finding new uses for things, making things, and improving things. I'm a student who is currently looking for a better job, one where I can make an actual difference.

This sensor is very sensitive and can pick up electrical signals from anything that uses power. It displays the amount of interference it picks up by sequentially lighting 4 led's one after the other. I have tested it all around the house and its been kinda fun to see how different things compare. It can also be used to follow house electrical wiring inside the walls, yes its that sensitive.

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Step 1: Program the Attiny 45

I used an Arduino Nano to program the Attiny 45 it was easy to setup and worked great. The code shown reads the analog input and uses that information to figure out how many led's should be on if any. The values at which each led lights up are dependent on the antenna, its resistance to ground, and the attiny's input sensitivity. These values will have to changed in the code to best match your personal setup. Sensitivity is adjusted by increasing or decreasing the resistance to ground on the antenna and by changing the led turn on values.

Step 2: The Circuit

Start by connecting one of the Attiny 45's analog inputs to the antenna then ground it using four 1 mega ohm resistors in series, after that wire the remaining outputs to light four led's. I used a solid copper wire for the antenna and wrapped it around a marker to get the spring like coil. It seems to work fine with 3 volts, so I used a AAA battery holder to power it. I recommend building it on a breadboard initially so you can see what works best for your antenna and modify the circuit or code as necessary.

2 People Made This Project!

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25 Discussions

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Sixsense

3 years ago

Hi! Sir, im from philppines and i like the design of your emf. Can you help me sir how to make an emf step by step. If its ok with you sir. Thank you!

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arduinomaster

3 years ago

We made an arduino with 16 shift registers that can turn on 128 lights. The problem remains "I'm thinking EMF disturbance to trigger the light". I will do more research, but my discussion group can not help with your trigger idea so far.

I started with an Freetronics starter kit cat.No.XC4262 from Jaycar 3 years ago. But best is to join a group to learn, exchange ideas and ask all your questions. Youtube also has many tutorials.

You can find my web link in here

https://www.instructables.com/id/EMF-detector-0-999...

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arduinomaster

3 years ago

You find my design here with instructions how to program the Tiny on my web site

https://www.instructables.com/id/EMF-detector-0-999-Hz-for-ATtiny-85/

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JasonS121

3 years ago

Can you share the process for programming the ATTiny45 using the Arduino Nano? I guess specifically how you did it. I have an Uno but I am assuming it requires additional shields or something for the 8 pin chip. Thanks and neat design.

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Khaleel123JasonS121

Reply 3 years ago

I followed an instructable on here, search program attiny with arduino. Uploaded by randofo. All you need is a breadboard or a way to connect to the pins on the attiny and a 10uf capacitor.

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Khaleel123

3 years ago

Sorry for the late replies, I haven't been getting emails telling me when I receive comments.

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arduinomaster

3 years ago

Nice design. I like the simplicity of it. I made one with an ATtiny85 and it works just fine.

No current limiting resistors needed with a 3Volt input. Simple but working software. The chip is a available on eBay or Element 14 in AUS. Good work keep it up.

1 reply
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davidvarner101

3 years ago

Hi, I'm wondering what the antenna is made out of, could you please give me the requirements for this instructable?

1 reply
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Khaleel123davidvarner101

Reply 3 years ago

The antenna is made of solid copper wire, similar to the kind used for doorbell wiring. All that's required for this project is : attiny 45 or similar micro controller capable of running arduino code, 4 LEDs, 4 1megaohm resistors, 3volt power source, 8" solid copper wire.

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arduinomaster

3 years ago

/*EMF detector instructables

https://www.instructables.com/id/Attiny-45-EMF-Sensor/?ALLSTEPS

written for ATiny 85

2 October 2015

improved code by by Robert Moller

*/

void setup (){

pinMode(4,OUTPUT);

pinMode(0,OUTPUT);

pinMode(1,OUTPUT);

pinMode(2,OUTPUT);

pinMode(A3,INPUT);

int val=0;

}

void loop(){

int val = analogRead(A3);

int del =30;

delay (1);

if (val>0 && val<=4){ digitalWrite(4,HIGH);

delay (del);}

if (val>=4 && val<= 6){ digitalWrite(0,HIGH);

delay (del);}

if (val>=6 && val<=8){ digitalWrite(1,HIGH);

delay (del);}

if (val>8){ digitalWrite(2,HIGH);

delay (del);}

else

{

digitalWrite (4,LOW);

digitalWrite (0,LOW);

digitalWrite (1,LOW);

digitalWrite (2,LOW);

}

}

1 reply
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dheeraj malviya

3 years ago

Hii. i am 11TH class student and want to make emf sensor for exhibition. can you please tell me from where i get that chip with 8 pins.

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lyzuxdheeraj malviya

Reply 3 years ago

Depends on where you live, i think people in America often use digikey, i live in germany and get electronic components from local stores or i buy them cheap and without shipping from china through Aliexpress, this takes weeks to arrive though.