I'm sorry I have to say this, but "scientific" and "paranormal investigation" is hard to swallow in the same sentence.
Now that you know that I think that you are wasting your time trying to find ghosts I will try help you.
First of all, forget about video and audio processing in the Arduino. You will need something a lot more powerful (a proper PC or at least something like Raspberry Pi).
The busy part of the burglar alarms is usually a PIR sensors
, not a barometer (air pressure sensor). Plenty of PIR code examples
Temperature and humidity is easy. There are countless little boards like this one
out there that have those sensors. There are also plenty of tutorials for it as well, such as the one on the playground
Barometer? Sure, same thing
Vibration is a bit trickier. There are gyros and accelerometers. I've never used them though.
What kind of EMF are we talking about? You'll have to specify the type and bandwidth you are interested in.
IR and thermal camera, just like audio recording, like I said previously are not going to happen inside the Arduino. You can trigger them easily, though and process the data with some other device, or just record it for your later inspection.
Controlling a servo motor is usually trivial. Plenty of tutorials out there
Detecting a shadow, on the other hand is going to be challenging. Perhaps a sudden change in light levels? But then what if a cloud passes over? Yeah... I'm not sure about this one.
Detecting movement? Sure. Laser tripwires or ultrasound distance sensors are cheap. Detecting movements of ghosts? Well... You'll have to figure that one out yourself.
You want to reproduce the results? You can certainly do that. But can you reproduce the cause
? I can demolish a house, but I can not reproduce an earthquake. Saying that me bulldozing a house is the same thing as an earthquake destroying it is not really proper science, even though the result is the same. Can you make a ghost do your bidding and parade in front of your sensors so you can calibrate them?
I skimmed over that Ovilus thing and the first thing I read is:
Disclaimers and Licensing
The OVILUS III is sold as an entertainment device only. We make no claim to the validity of the data received by this device.
Not really reassuring, but the more interesting part is this:
Remember the odds of this device saying a word that is contextually correct is 1 in 2047
And in the units with phonetic speech the odds are only 1 in 71.
This means that the device has a few floating inputs and it matches their values with a very limited dictionary filled with (I would presume) words that are likely to be interpreted to be in context (how did the creator of the device link the "energy levels" with the dictionary entries is beyond me, though). So no matter how benevolent a ghost there may be around, all you'll hear is "death", "kill", "torture" or similar crap. The device will never "channel" Mother Theresa or Gandhi, because you are looking for ghosts and ghosts are supposed to be spooky. You want to have the hair stand up on the back of your neck, your blood chilled and scream like a little girl.
You will throw away the device if it starts to talk about dandelions and world peace.