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There are a couple of Android apps to detect EMF (for ghost hunting and for hazard-protection). I tried a free one which did not work. Some I can't seem to download. Has anyone tested them (against a fan, microwave or magnet, etc.) and see if it really works and is accurate at all?

Here are the ones that claim to be work.

Ghost Hunter (EMF, EVP, SCAN) $0.99

Entity Sensor Pro $9.99

I know it might be dependent on phones, too, but it is acceptable if it works on any phone.

Edit: Please do not be distracted by the mention of ghosts in this question. The question is about EMF only, not ghosts. Since these apps are mostly used for ghost-hunting, I have listed them. My question is these apps can detect EMF and, if so, how accurately?

Oddthinking
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TheTechGuy
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  • even if EMF existed, a piece of software could never detect it without appropriate hardware. So the question should be whether Android phones have hardware capable of detecting EMF (a separate question could be whether EMF exists in the first place). – jwenting Nov 15 '11 at 07:03
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    Three problems I have with this question (and so I voted to close as "not constructive): **1.** What proof is there that ghosts emit/cause EMF effects? **2.** What proof is there that ghosts are real? **3.** How can others verify what "seems to be working" (e.g., which brands and models of phones did you use in your tests, _as jwenting just commented about more generally_)? – Randolf Richardson Nov 15 '11 at 07:55
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    @Randolf, I think **1** and **2** are not relevant. If Android phones cannot detect EMF in the first place (and these apps are just generating random answers), they don't matter. Note the OP asks about testing them against known EMF sources, not ghosts. – Oddthinking Nov 15 '11 at 09:09
  • @Oddthinking: I thought it was relevant because the author clarified the use by writing "_...to detect EMF for ghost hunting (and for hazard), I tried the free one which did not work..._" – Randolf Richardson Nov 15 '11 at 09:29
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    ghost hunting is just use, which ok is another topic. The question is can it detect EMF from Microwave etc. I have stated in the question `I know it might be dependent on phones` so I know it is hardware dependent. But the question is, are these software scams or not. – TheTechGuy Nov 15 '11 at 14:24
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    As I understand it the EMF sensor in all android gets overload by known sources as it is meant only to detect trace amounts. So these apps really work but only on real ghosts. So if you see a ghost but it does not show up on the emf sensor its just a hoax. – Chad Nov 15 '11 at 22:04
  • The Radio inside the phones can send and receive RF, some very small part of which is EMF, however apps on the phone are not allowed to access this hardware at a low enough level to be useful for EMF detection and interpretation. The magnetometer in most phones is very insensitive and very slow, so while it can report very large fields that don't vary much, it isn't going to be good for finding local magnetic phenomena from a distance of more than a few feet. Those apps likely use the magnetometer, but they are as limited as the magnetometer in what they can sense and report. – Adam Davis Nov 19 '11 at 01:53
  • If you believe in ghosts, it is concludent to believe in ghost sensors - not only being able to detect ghosts, but behaving ghostly like being often invisible, working only on full moon and such. Pasta can save you from ghost phones. – user unknown Feb 03 '12 at 01:37
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    @jwenting: the fact that ghost do not create EMFs ( (electromagnetic fields), as they do not exist, does not mean EMF do not exist either. – nico May 19 '12 at 09:10
  • I have toyed with a few apps at a friends house one night. It does pick some things up because I have felt sensations myself of energy around me, temp fluctuations etc. After I felt it the meter on my phone went off the charts, and the more I felt it the higher the value. Also my digital recorder caused a false positive. The closed the device got to my phone the stronger the signal was. It faked me out for sure. Sham I did that I felt nothing. Also when this happened I did get an evp response. These things have always interested me so I tried it out. I have been wanting to play around with the –  May 19 '12 at 06:35
  • @nico true, but was talking about EMFs as emitted by supernatural whatevers :) – jwenting May 21 '12 at 08:53
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    To the person who doubts the existence of emf...pick up a physics book...or a general science book. Ghost may or may not be real(skeptic here,but I do "ghost hunt" for fun though. I live a couple blocks from and friends with the family that owns the original springs hotel okawville Illinois apparently. It is a well known haunted hotel...it is old as frak, but of all the times I have stayed there and used various emf devices I sniped off ebay...was fun times but in my opinion it is nothing more than a creepy old hotel. –  Jul 19 '12 at 11:44
  • Please explain the abbreviation EMF! – reinierpost Jul 19 '12 at 17:17
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    Can the OP catch a break here? Jeez he asked about a phones capability to detect EMF. He did not ask about opinions on ghosts. He explicitly said "Please do not be distracted by the mention of ghosts in this question" - yet more than half of the responses are related to existence or non-existence of ghosts. One even questioned the existence of EMF!...Really?!?. Come on folks, his actual question was a good one, and I have the same question which is what brought me to this post. – hardba11 Jan 14 '14 at 18:27

2 Answers2

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Yes, but not in a way that is likely to detect Ghosts if they exist

Mobile phones are, by definition, devices that can detect EMF (which is electro magnetic field see wikpedia) since their ability to communicate depends on radiofrequency fluctuations in EMFs. 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 (see wikipedia again). It seems unlikely that software can turn them into devices that can detect general fluctuation in EMFs.

Some apps claim to use the magenetometers to detect EMF. And stand alone EMF detectors seem to be calibrated in units like milliGauss (see here for an example) which is a measure of magnetic field strength (wiki definition). This suggests that the sort of EMFs sought are low frequency changes in magnetic fields. So perhaps this is more likely to work as that is just what magnetometers can do. However, there are many 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. As one useful site on sensors reports:

The magnetometer is commonly found on mobile devices such as smart phones 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.

Even the believers don't seem to take the idea of detecting ghosts via phones seriously. This app claims it is is "just for fun". This discussion (I think fairly characterised as taking place on a believer site) dismisses the idea that phones can be reliable ghost detectors.

So, yes phones can detect EMF. But ghost detection apps are likely just reporting random background noise.

matt_black
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    I think testing such an App against a real magnetometer placed next to a fan will clarify if these Apps are scams or just for fun. – TheTechGuy Nov 15 '11 at 14:29
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    not completely, Believer. That would show whether they can detect EMF or not (at least of a very specific field type), not whether they can detect ghosts (which they claim to do). – jwenting Nov 16 '11 at 11:02
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    @Believer: There's a huge scale between spam and a device that uses very low quality measurements that make it unsuitable. – Christian Nov 16 '11 at 18:05
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    Actually ghost is out of question. That is just my own curiosity. The question it, can it detect EMF and how accurately if it can? I have tried the `EMF Hazard` App on a fan. It did not work. – TheTechGuy Nov 16 '11 at 20:06
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    +1 for "Mobile phones are, by definition, devices that can detect EMF". There's even a tongue-in-cheek "Tricorder" app for Android that shows various wireless signal strengths under "EM Spectrum". – Simon Nov 16 '11 at 22:45
  • So I tested one on a iPhone: Ghost Radar. No evidence it responds to actual magnetic fields or anything else meaningful. Its own explanation of how it works is typical mystical mumbo jazzed up with references to quantum effects. Not even worth the $1 for fun value. – matt_black Nov 18 '11 at 19:14
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    "Yes, but not in a way that is likely to detect Ghosts if they exist" As much as I won't deny the statement, we really can't define "ghost". For example, a "ghost detector" application could detect a specific kind of ghost that sends SMS messages. Who knows, if they could knock on tables and all... :) – Camilo Martin Apr 16 '12 at 11:48
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They can detect magnetic fields, or are at least designed to.

If your phone doesn't have the hardware for it, you shouldn't be able to see it on the App Store (assuming it was programmed properly).

A little off topic, but they can detect humidity, pressure, temperature too, which I didn't know before this :)

Oddthinking
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Muz
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