EMF = Electromagnetic Field Detector

An EMF meter can measure AC electromagnetic fields, which are usually emitted from man-made sources such as electrical wiring, while gaussmeters or magnetometers measure DC fields, which occur naturally in Earth's geomagnetic field and are emitted from other sources where direct current is present.

Make your own EMF meter

EMF measurements are measurements of ambient (surrounding) electromagnetic fields that are performed using probes. These probes can be generally considered as antennas although with different characteristics. In fact probes should not perturb the electromagnetic field and must prevent coupling and reflection as much as possible in order to obtain precise results.


The Antenna can be calulated from a German web site.
I have built in the intenna on the circuit board.
I put in from 0 Mhz to 999 MHz and it tells me the messurement for this broad range of frenqency.
The site is in German but easy to understand. 
niedrigste Frequenz = lowest frequency
hoechste Frequenz    = highest frequency
Quadrat-Kantenlaenge = square edge lenth
AntennenHoehe = Antenna hight
Gesamtlaenge Draht(in cm) = total wire lenth

Design files

Ones the site editor will understand my request 
will link to this site or a better provider.
With a provider without comunication  difficulties understanding that the payment options must be to my terms.
No one wants to give anyone access to your account and take out what they like.
It's like handing out your wallet.
No one is reading my emails. I contsantly get the same ramdom reply.
If you know of a better web site let me know.

Design files


// EMF Detector for ATtiny 85 MK5
// 12/11/2015
// original code/project by Aaron ALAI
// modified for use with ATtiny 85 EMF detector

#define NUMREADINGS 15 // raise this number to increase data smoothing

int senseLimit = 15; // raise this number to decrease sensitivity (up to 1023 max)
int probePin = A3; // analog 5
int val = 0; // reading from probePin

int LED1 = 2; // connections
int LED2 = 1; // to
int LED3 = 0; // LED
int LED4 = 4; // bargraph

// variables for smoothing

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

void setup() {

pinMode(0, OUTPUT); // specify LED outputs
pinMode(1, OUTPUT);
pinMode(2, OUTPUT);
pinMode(4, OUTPUT);

pinMode(A3, INPUT);

for (int i = 0; i < NUMREADINGS; i++)
readings[i] = 0; // initialize all the readings to 0

void loop() {

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 ...
digitalWrite(LED1, HIGH); // light the first LED
else{ // and if it's not ...
digitalWrite(LED1, LOW); // turn that LED off

if (average > 250){ // and so on ...
digitalWrite(LED2, HIGH);
digitalWrite(LED2, LOW);

if (average > 450){
digitalWrite(LED3, HIGH);
digitalWrite(LED3, LOW);

if (average > 650){
digitalWrite(LED4, HIGH);
digitalWrite(LED4, LOW);


Available as kit

EMF detector parts

PC Board
Attiny 85
led's cleart 4x
1M resistor 4x
100R resitor 4x
button cell socket
button cell 2025 3Volt or LIR 2032 3.6 Volt

including postage within Australia
​All prices AU $
$ 15.00 without battery
$ 18.50 with LIR 2032 battery

Notes and erata

A connection on the board is missing and has to be added with a short wire.

The web site Arduinomaster will be available soon, but is only a link to this web site anyway.