Electromagnetic Field Sensor – vero layout

I have wanted to experiment with some EMF (electromagnetic field) sounds and figured I might as well make a vero layout for this EMF Sensor schematic. It’s from an article by Frank Donald that I found online. Pretty simple, using a TL071 opamp, a power inductor, a 2m pot that adjusts the frequency, and just a couple of caps and resistors. I threw it together in no time.

What is EMF?

“EMF stands for “electromagnetic field”.  EMFs are invisible areas of energy, or radiation, that are associated with the use of electrical power and lighting.  EMFs are a combination of electrical and magnetic fields. The strength of an EMF is related to the amount of electricity in use and the electrical potential in the electric circuit.” – National Institue of Environmental Health Sciences

and why would I want to record it?

Because it sounds weird, and if you are here, you must like weird sounds. I hope to have some solid samples recorded and posted soon.

With a device like an EMF sensor, you can listen to the hidden sounds that your modem, cell phone, and computer monitor make. Furthermore, you take an EMF sensor out into the world and listen to electrical boxes, phone network relays, powerlines, and even toxic radiation (according to articles, not sure my device does that).

From the NIEHS website.

My EMF sensor build

I subbed the 1mH Power Inductor for a 3mH but plan on testing both now that I have a working board built. I read someplace that the lower the value the higher the frequencies passed.

Note: The power inductor passes power and requires a non-grounded connection if you plan on using an external probe.

I also had to use a 1m pot and a giant 220 uF capacitor as that was all I had on hand, it works but I’m sure the 2m I have on order will work even better (2.2m on the schematic).

POTAR Design Devices EMF Probe

Here is my finished EMF Probe!

  • 1 Power Inductor Probe
  • ON/OFF/PUSH Switch
  • Push Button for Switch
  • Sensitivity Control
  • 1/4″ Output
  • PROBE connected by RCA (note, must use plastic base jacks)
  • 9 Volt Battery Operated


I collected these sounds while walking around my neighborhood. Alleyways near businesses seem to have pretty good signals.

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