In a survey conducted by CBS News in 2005, it was found that 48 percent of Americans believed in ghosts. Other surveys have put the number at anywhere from around 20 to over 50 percent. While such figures certainly don't imply that ghosts are real, they do suggest that belief in them is relatively common. When someone does suspect that a ghost is present in their home or business, they will sometimes call in "experts" to ascertain if that is, in fact, the case ... and what sort of gear do these ghost hunters use to detect said spirits? We decided to find out.

Given that ghosts are frequently thought of as non-physical beings that can only be seen by people like Jennifer Love Hewitt or Haley Joel Osment, one might wonder how regular human technology could possibly register their presence. We're told that it all comes down to what people are made of.

"We're built out of energy – atoms and molecules," says Rona Anderson, co-partner in the nonprofit Paranormal Explorers ghost-hunting group, which operates out of Edmonton, Canada. "I just think it's an internal piece of us that stays when our bodies deteriorate."

"When somebody dies, do they go into another dimension, with a very thin wall?" asks her partner, Ben Myckan. "I think that's sort of what it is. You can't destroy energy, it's just in a different dimension."

So apparently, it's not so much about looking for lost souls as it is looking for unexplained energy, or evidence of its manipulation.

EMF meter

When it comes to detecting energy, an electromagnetic field meter is definitely a good tool to have. "At a haunted location, erratic and fluctuating EMF levels are likely to occur," says Alexandra Woodfield, of UK-based paranormal gear retailer TomsGadgets. "Out of all the paranormal tools, the EMF meter is an excellent introduction to ghost detecting. Although currently there is no device that can conclusively detect for the existence of ghosts, the EMF meter is the closest tool on the market."

Rona and Ben use their EMF meters partially to identify man-made electrical fields within buildings, as some researchers have suggested that supposed ghost sightings could be caused by such fields interacting with the human brain. The couple are also interested in detecting EMFs in places where no electrical features are present, however, as those could be caused by ... well, you know.

Thermometer

Anderson tells us that ghosts both gather energy from rooms and release it into them, causing highly localized drops or rises in temperatures – hence the "cold spots" you might have heard mentioned in horror movies. A good thermometer will confirm that such perceived changes aren't just due to heebie-jeebies on the part of the observer, and will document exactly how large the changes are. "It has to be at least a ten-degree drop before we think, 'Oh, well maybe something's happening in this room'," she explains.

Besides a regular thermometer, Rona and Ben also use an infrared digital point-and-shoot model, that can instantly obtain temperature readings from any point that it's aimed at within a room.

Digital audio recorder

Ghosts supposedly do sometimes want to talk to us, but not in a way that's easy to understand in real time with the unaided human ear. Proponents of Electric Voice Phenomenon (EVP) tell us that if you record the room noise while asking questions aloud to the ghost, although you may hear nothing in response at the time, you'll be able to make out some replies when you play back the audio file. If you've heard EVP on any of the numerous paranormal reality TV shows, however, then you will know that a lot of those "replies" can be pretty faint and ambiguous.

Having to pick out the ghost's end of a conversation after the fact kind of limits what you can talk about, but a new product offers a way around that limitation. Connecticut's DAS Distribution makes a gizmo called the RT-EVP, which uses parallel microprocessors to simultaneously record audio and play it back on a time delay – that delay can be from 1 to 60 seconds, as set by the user. If you were to set the delay for five seconds, for instance, you would ask a question, then hear a recording of yourself asking the question, followed by an ongoing playback of whatever audio the device recorded in the room just five seconds ago.

Because it can pick up sounds down to 15Hz, which is below the threshold of human hearing, it can indeed "hear" things that we can't ... possibly even the voices of lost loved ones, according to product designer and DAS president Gary Galka. "Since the completion of the RT-EVP instrument, we have received three beautiful etheral messages from our daughter Melissa," he tells us.

Ghost Box

While EVP can allegedly be found in ambient sound, it's said to be easier for ghosts to work their voice messages into white noise, which is where something called the Ghost Box or Spirit Box comes in. A Ghost Box scans across local radio frequencies, supposedly allowing ghosts to use stray bits of static, squeal and other noise to form and/or carry their messages. The RT-EVP, in fact, has a "frequency sweep" feature that lets it operate as a Ghost Box.

For her part, Anderson believes that Ghost Boxes have their place, but can't be relied upon. This is due to the simple fact that what is being heard could very likely just be distant radio broadcasts. "The only way you know is probably what they're saying," she says. "If they say 'Help me,' or 'My name is Joan,' you're going, OK well that doesn't sound like a radio station."

A somewhat similar device is the Ovilus. It takes temperature and EMF readings, combines those readings into one number, chooses a word from an onboard database that matches up with that number, and then "speaks" the word aloud. The idea is that a ghost, knowing this device is present and presumably knowing how it works, will purposely make changes to the temperature and EMFs so that it can communicate through the Ovilus. Should you not want to shell out for the device itself, though, you can always download the iOvilus app to your iPhone. Just don't believe everything it tells you ...

The Ovilus "works" on the same principle as Ouija boards, which many ghost-hunters steer clear of, as they are said to open up portals that anyone or anything could come through. "You're not necessarily going to get who you think you're going to get," says Anderson, of the boards. "We've had people who have called us to come and do an investigation because they've used a Ouija board and someone's dropped in and hasn't left."

In other words, go ahead and download iOvilus, but don't blame us if you end up getting sucked into your TV.

Motion detector or beam barrier alarm

"These are also used for security by creating an invisible barrier to detect for any movement," says Woodfield. "Paranormal activity can trigger these beams and set off an alarm. Of course it is important to set up a digital video camera to eliminate tampering from other people or animals."

Rona and Ben also use a Trail Master camera trap, in which a motion detector is wired directly to a digital still camera, which snaps a shot whenever the detector is tripped. The setup is commonly used in the wilderness by wildlife photographers, or even cryptozoologists looking for Bigfoot ... but that's another article.

Infrared wireless cameras

When it comes to digital video cameras, Paranormal Explorers and most other groups use the infrared variety, running several of them into a split-screen display on a laptop. That way, they can show the client what their eyes might be missing, and make a DVD copy of the footage for them. Just what might that footage show?

"Sometimes you might just see something floating around," says Myckan. "You might see just a ball of light ... Sometimes you might even see a mist, or an ectoplasm, and it might be in the shape of something."

"Usually, when people watch it on TV, they really seem to have an epiphany, and they seem to be not frightened anymore," adds Anderson.

Digital still cameras are also considered essential gear, both for showing up things that us humans can't see (such as in Paranormal Explorers' shot below, possibly), and simply for documenting locations where investigations are carried out.

Other bits of gear used by Paranormal Explorers and/or recommended by Woodfield include parabolic microphones, flashlights, two-way radios, night vision equipment, FLIR thermal imaging cameras, and even dowsing rods.

It could be that one of the most useful things to have, however, is simply good "ghost sense."

"When we go into a house that is supposed to be plagued by stuff, I do rely on my intuition," says Anderson. "Usually I can pick up right away if there are spirits."

So, is it possible that any of these instruments – or even the human subconscious – could be detecting anything from the great beyond? We look forward to receiving your comments ... just remember the advice of Dr. Egon Spengler: "Don't cross the streams."