Hi guys ! i'm facing a problem with an Arduino EMF project i'm trying to achieve.
I would like to know if my antenna is near or far from the screen of my computer using EMF of my screen.
So, i used a 3,3 Ohm resistor plugged into GND and A2 PIN of Arduino UNO. And an electric câble as an anthena.
I used this code to read EMF values:
const int sensor=A5; //set the sensor to pin A0
void setup(){
Serial.begin(9600);//initialize the serial monitor at 9600 baud rate
}
void loop(){
int sensorValue=analogRead(sensor);//create a var to store the value of the sensor
Serial.println(sensorValue);// print the value of the sensor on the serial monitor;
delay(100);
}
And actually it return positives values and return to 0 regularly, like a hearthbeat...
Does someone see why ?
The interference you pick up is a waveform that goes positive and negative. The Arduino can only measure positive voltages, any negative voltages will just read as zero.
Most of the pickup is 50 or 60 Hz depending on where you live, so that explains the regular heartbeat you see.
You are measuring the electric field, not the electromagnetic field - no magnetic component is involved.
My laptop screen gives about 50mV signal around 100kHz (detected with a scope probe), whereas the general mains frequency pickup totally drawfs this at tens of volts.
A band-pass filter and amplifier are probably needed to do this well.
iPawns:
Hi guys ! i'm facing a problem with an Arduino EMF project i'm trying to achieve.
I would like to know if my antenna is near or far from the screen of my computer using EMF of my screen.
"Near" ... "Far" ... these words impart no quantitative information. You undoubtedly have an image, in your mind, of what you wish to achieve, but we can't see that image, so it's very important for you to be comprehensive in your communications. Otherwise, we are left to scratch whatever exists on the top of our heads.
Another example: "I would like to know" ... then why don't you just look? In the vacuum of information provided, the question, though potentially funny, is quite valid. I have no idea why your visual faculties are inadequate for the task, because you have given us no justification for this goal. And, though it may not be apparent to you, such detail could very likely, make all the difference in how we address this problem.
MarkT:
You are measuring the electric field, not the electromagnetic field - no magnetic component is involved.
My laptop screen gives about 50mV signal around 100kHz (detected with a scope probe), whereas the general mains frequency pickup totally drawfs this at tens of volts.
A band-pass filter and amplifier are probably needed to do this well.
thanks , yes i measure electric field ^^"
i'll try with a band-pass filter and an amplifier...