Making the Arduino EMF detector

Aaron ALAI's EMF detector project looked so simple and fun I had to give it a try. After putting it together, I liked it so much that I went and built a more 'meter-like' version using an LED bargraph -

EMF_detector_LED_bargraph2.jpg

Arduino code is available here.

As I mention in the vid, I was a bit concerned the wire probe might be affected by the LEDs I mounted nearby -- but from what I can tell, it still seems (relatively) accurate. A short walk around my workspace even revealed a few items I'd forgotten were plugged in - helpful! I'm sure there are many ways in which this project could be used/repurposed/modded - I plan on converting the readings to sound when I get the chance. If you make one be sure to submit a pic to the Flickr pool and/or send us a link.


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Comments

Oldest comments listed first.

Posted by: dude on July 26, 2009 at 2:54 PM

I think there is something odd about the code

In the code that comes with this project I see:

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

It should be noted that the smoothing doesn't happen without removing the first line of those shown here. And then you get a problem when you start over from index = 0; so this should be changed to:

readings[index] = val;
total = 0;
for(int i = 0; i < NUMREADINGS; i++){
total += readings[i];
}
index += 1;


Posted by: CS on August 17, 2009 at 7:57 PM

This could be useful for activating something else; like an inductive relay, but in a non-contact fashion. (Like triggering a low-voltage circuit when a motor starts)


Posted by: Boffincentral on November 16, 2009 at 4:50 AM

Excellent suggestion. I have a need for something like that to trigger the big dust collector when I use the saw or planer. I could even trigger it at higher levels as the power board is on all the time. I just sniff for the higher amperage and even have a delay cut off. Awesome project!


Posted by: Boffincentral on November 16, 2009 at 4:51 AM

Excellent suggestion. I have a need for something like that to trigger the big dust collector when I use the saw or planer. I could even trigger it at higher levels as the power board is on all the time. I just sniff for the higher amperage and even have a delay cut off. Awesome project!


Posted by: Nitin Kushwaha on November 21, 2009 at 12:34 PM

Similar but without Arduino

Hello, It is really gr8!

can you please tell me, how to get this done without using a microcontroller.
I am working on a similar model as well.
nknitinkushwaha[at]gmail[dot]com

Thanks.


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