The Truth About EMF Apps

It’s been a long couple of months for me. As with any good research, it’s time-consuming. It seems like not too long ago, what started as an innocent debate, became a heated argument and eventually a grueling battle for common sense. As with most things related to the paranormal, this argument was sorely lacking in facts, and it would soon be apparent that common sense would not prevail unless I set out to prove my point indisputably. What was that argument you might ask?

“Do the EMF detector [ghost hunting] apps on a smartphone work?”

I should start from the beginning. A forum member, new to ghost hunting, just wanted to know if there were any good tools out there that they could use on their phone. We’ve all been there. Some of us are still in that place. It was such a simple question that I felt required many layers of explanation to answer properly. This was not a simple yes/no type question. Was there a specific app they wanted to know about, what kind of app were they talking about, and what exactly constituted a “working” app? If the question was do the apps detect ghosts; that is highly debatable. If the question is, do any of the EMF detector apps actually detect electro-magnetic fields, that is an answer we can get tot he bottom of.

As the conversation went on it became apparent that there were some key elements of the conversation that would quickly get out of hand as soon as others joined the debate. Advocates and creators of specific applications in the Google and iTunes stores began flooding the thread with their sales pitches and “paranormal evidence.” I myself having a background in electronics had a few comments of my own to interject into the conversation. To paraphrase, I did not feel that many of the ghost hunting tools that were being discussed had any merit because I know, from experience, that the hardware in cellphones did not support the functionality that the app creators claimed their product had. Needless to say, even with a page’s worth of facts and specs about cellphone hardware, some people were not taking my word for it while the app creators participating in the discussion dug in their heels. While not begrudging someone the opportunity to make some money selling a novely app; to hear them try to pass of false information as fact was really upsetting.

I wasn't long after my statements, about the technical specs, that phones could not be used to detect EMF with the existing hardware, I received the following information from several app creators via boards and private messenger as a means to persuade me of my error.

EMF Pro "This app uses the magnetic sensor [compass] of your phone and displays the reading with a line of LEDs and a classic needle meter. You can switch between units of measurement (uTesla and Gauss) and change the range of measurement from the settings.”

Ghost Radar "[Ghost Radar] is the original application designed to detect paranormal activity. Ghost Radar attempts to detect paranormal activity by making various readings on the device. Traditional paranormal equipment can be easily fooled when simple mundane bursts of normal energy occur. Ghost Radar sets itself apart by analyzing the readings and giving indications only when interesting patterns in the readings have been made.

Ghost Radar also includes a voice to let you know when interesting words have been detected. Please note we offer no guarantees of accuracy or any warranties, therefore, since results from this application cannot be verified scientifically the app should be used for entertainment purposes.”

SGK1 Ghost Hunting Kit "The EMF Detector uses the Magnetometer built into your Android Device (some devices do not have this, in which case the feature will not work).”

I was also directly confronted by the maker of an App that I will not directly name due to his comments being redacted and deleted before I started writing this article. However, in short, I was told I didn’t know what I was talking about and given a glimpse of the code that the designer used to make the phone detect EMF through the compass. The code, which was in line with his explanation, showed that the app did in fact use readouts from the magnetometer as a compass. When it detected a pull towards the negative or positive range, it converted the measurements, based on axis, to a readout in the app screen. I was then told that testing the app was a simple matter of putting it near a magnet or screws in a wall [i.e., ferrous material] to watch the readout change. However, when I asked the developer if he had an understanding of geomagnetism and that it was not the same as an electromagnetic field, he declined any further debate on the matter and claimed I must have been dropped on my head as a child.

Frustrated, I issued a challenge to anyone still arguing. Give me a month to review your app, and give me permission to look under the API to evaluate the merit of the code being used and how it utilizes the hardware. Needless to say, those branches of the thread became very quiet. And, yet still, many of the users were still debating the merit of these apps even though I had, what I thought, clearly explained that the functionality their app claimed to have simply was not possible with the device. Feeling defeated, I decided to take a new approach.

After logging off the board that night, I wrote a letter to three major manufacturers of cellphones with some technical questions related to the debates I had just had. The main argument being: many ghost hunting apps claim that they are using the phone as an EMF detector. Was that even possible? If I was going to end the conversation I needed to make absolutely sure I had my facts straight. If I was wrong, I was willing to admit it.


My name is Ashton Rogers, and I am paranormal investigator based out of North Texas in the United States. I am researching a subject, and I was hoping that I could get a hold of someone who could answer some general technical questions for me in regards to cellular phone hardware.

There are many applications that can be downloaded from the google play store that claim to be "ghost hunting" apps. Over 90% of these apps claim that they function through the means of using the phone's hardware as an EMF (electromagnetic frequency) detectors, and generators. Setting aside any debate about EMF's and their relationship to the paranormal, what I want to know is: Is it even possible that a program could repurpose a smartphone's hardware to perform the functions.

I understand that cellphones use EMF to find a cellular signal from the 2g to 4g band. However, that is in the high end of the GHz spectrum. These apps are claiming that by using the magnetometer on the phone; it can properly measure EMF in the 0.1 - 10.0 mG range. This doesn't seem like something that would be possible to me without physically altering the hardware of the phone. For one since it isn't purposed that way it would not be accurate and probably the devices own equipment would interfere with the readings. Second I don't see the phone having a capacitor large enough to act as a sensor that could be purposed as such by an application without rooting the device.

Any light or thoughts that could be shared on the subject at hand would be greatly appreciated. I am trying to put together a research paper to be published, and I would love to have the facts straight from the source of a major manufacturer. If there is someone better to contact with this question who would be willing to write back, please let me know.

Thank You, Ashton Rogers”

Surprisingly it only took a few days to get a response to find out that my question was forwarded on to a manager in the hardware design department of [unnamed company]. And after another week of waiting, I received a direct reply from two different companies within days of each other.

The following response was from LG:

“Dear Ashton

Thank you for your question, your research sounds interesting. As you may already know, the answer to your question is not a simple yes or no.

Mobile phones are, by definition, devices that can detect EMF since their ability to communicate depends on radiofrequency fluctuations in electromagnetic fields. So, apps on a smartphone can, at least in a trivial sense, detect EMF and alter it when they send a signal. Unfortunately, mobile phones are designed to detect only specific frequencies from about 800 to 2.2 GHz which are the frequencies of 2G and 3G cellular phone systems. It would seem unlikely that software can turn them into devices that can detect a general fluctuation in EMFs.

As you stated, some apps claim to use the magnetometers to detect EMF. Standalone EMF detectors seem to be calibrated in units like milliGauss which is a measure of magnetic field strength. This suggests that the sort of EMF’s sought are low-frequency changes in magnetic fields. So this is more likely to work as that is just what magnetometers can do. However, there are many sources of interference that alter the background magnetic field of the earth (which is what magnetometers detect) as anyone who walks around a built-up area while using the compass app on their phone will know. Large steel-framed buildings, cars, iron lamp-posts all cause major field changes that overwhelm the background field. I reached out to a supplier for our magnetometers with your question and received the following response.”

[The magnetometer is commonly found on mobile devices such as smartphones and tablets, but it is one of the most difficult sensors to interpret. It is commonly called a compass since it measures the strength of the magnetic field in three dimensions but does not necessarily point North. In fact, magnetic interference can cause it to behave unpredictably, as often seen in augmented reality apps.]

In conclusion, to answer your question, the hardware inside the phone could, in theory, be used to detect magnetic fields, and software could possibly be written to interpret the readings of the magnetometer. However, since the phone was not designed with this purpose in mind, it is not properly configured to give an accurate reading in a manner consistent with a stand-alone device. Also, it would give no indication of electric charge in the wave. Also, your comment about the accelerometer is right on the money as it would give off its own signature. In addition, you may also find flaws in readings because of the digitizer which acts as the screen interface by using static detection when being touched which can interfere with a magnetic field.”

I also received the following response from Samsung:

“Dear Ashton,

Thank you for contacting Samsung Technical Support.

We see that you wish to know if it is possible for a program to re-purpose the hardware of the phone for the proper functioning of the application. I’ll help you with the available information.

We appreciate the efforts you are making for the research to be successful. To keep you informed, an application can be changed in all ways needed, but it will not be able to change the hardware of the phone for it to function full-fledged. As per Samsung, there is no such possibility of changing the EMF range on the phone without performing any changes in the hardware/software."

So what does this mean? In short, it means exactly what I was saying from the start. Paranormal debate aside, the magnetometer inside a smartphone cannot, and will never detect electromagnetic fields or their changes. But why? What the heck is this piece of magic equipment hidden inside your phone that these app creators claim can be tapped to give EMF readings?

A magnetometer is an instrument that measures magnetism—either the magnetization of a magnetic material like a standard ferromagnet, or the direction, strength, or relative change of a magnetic field at a particular location. The first magnetometer capable of measuring the absolute magnetic intensity was invented by Carl Friedrich Gauss in 1833 and notable developments in the 19th century included the Hall Effect, which is still widely used today. Magnetometers are widely used for measuring the Earth's magnetic field and in geophysical surveys to detect magnetic anomalies of various types. They are also used in the military to detect submarines. Consequently, some countries, such as the United States, Canada, and Australia, classify the more sensitive magnetometers as military technology and control their distribution. Magnetometers can be used as metal detectors: they can detect only magnetic (ferrous) metals, but can detect such metals at a much larger depth than conventional metal detectors; In recent years, magnetometers have been miniaturized to the extent that they can be incorporated in integrated circuits at very low cost and are finding increasing use as miniaturized compasses as found in the accelerometers of smart-phones.

So, a magnetometer can detect a magnetic field. Logically it should be able to detect an electromagnetic field, right? No. As it turns out, it’s a little more complicated than that. An Electromagnetic Field is defined as: “A field of force that consists of both electric and magnetic components, resulting from the motion of an electric charge and containing a definite amount of electromagnetic energy.” Thus meaning there are extra components to what makes a field of energy both magnetic and electromagnetic.

The area around a magnet within which magnetic force is exerted is called a magnetic field. It is produced by moving electric charges. The presence and strength of a magnetic field are denoted by “magnetic flux lines.” The direction of the magnetic field is also indicated by these lines. The closer the lines, the stronger the magnetic field and vice versa. When iron particles are placed over a magnet, the flux lines can be clearly seen. Magnetic fields also generate power in particles which come in contact with it. Electric fields are generated around particles that bear an electric charge. Positive charges are drawn towards it, while negative charges are repelled.

A moving charge always has both a magnetic and an electric field, and that’s precisely the reason why they are associated with each other. They are two different fields with nearly the same characteristics. Therefore, they are inter-related in a field called the electromagnetic field. In this field, the electric field and the magnetic field move at right angles to each other. However, they are not dependent on each other. They may also exist independently. Without the electric field, the magnetic field exists in permanent magnets, and electric fields exist in the form of static electricity, in the absence of the magnetic field.

Thus, by that definition, the test parameters given by the app creators are proven to be invalid. His test only proves that the magnetometer can only detect magnetism and geomagnetism which can exist completely separate from electrical energy. As proof that the hardware cannot detect “energy,” I held my phone up to several non-magnetic live circuits and statically charged items that I was able to pick up with a static meter. Unsurprisingly, none of the objects registered.

I will note, that objects with electromagnetic energy did make the readout change; but this is only because the magnetometer can pick up on the magnetic reading of objects in question. The readout it is giving is simply an indication that there is a level of magnetic pull. There is no relationship or measurement to the amount of electrical energy that exists within that field. Thus, the misrepresented reading converted to microtesla or milligauss, as common with an EMF detector, is misleading as it suggests that the magnetic field detected also contains electrical energy when it does not. Likely what you are detecting is the magnetic field of the wiring itself, bits of metal, or geomagnetic fluctuations due to geography. While these readings could be potentially useful, it’s the misrepresentation of the presented data which is upsetting. After all, if you knew you were simply paying for a compass, would you still purchase the app?

Phone apps and hardware do not detect true EMF, period. This is confirmed by the hardware manufacturers and science. EMF is measured using capacitors which store ambient charges and are then read out by a meter based on how much energy is put into the capacitor. Unless you theorize that spirits, ghosts, or supernatural agents are simply magnetic, my recommendation is these apps shouldn’t be considered much more than a novelty item for your amusement. In either case, you could achieve the same result with the compass app, so save your hard earned money.

About the Author: Ashton Rogers is the lead investigator of NTParanormal Investigations, a scientific research team based out of Fort Worth, Texas. He has been researching the paranormal with his team of experts since 2013 and worked and consulted on over a hundred cases. Ashton is an engineer with a background in electronics and media development. When he’s not investigating cases, Ashton is a writer. Author of the book: After Dark Paranormal Investigations, a syndicated columnist, and several fictional works as well. In addition to investigation and writing, he is the executive producer of his team’s web series and monthly podcast.

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