RSSAaron 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 -
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.
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;
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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)
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