Notebook and Pens - for taking notes and drawing
Extra Batteries - I cannot stress this enough. Batteries have a tendency to die at the most inopportune time
Flashlight Please use flashlights for safety, not as investigational tools! It is safer to let your eyes adjust to a low light situation than use flashlights. Only use a flashlight when absolutely necessary. If possible, get a night-vision friendly flashlight with a red filter - oh - and anything hands-free is a plus as well.
CameraClick for more info
Audio Recorder - This is the recorder that I and some others in the group are working with now. We recommend visiting a shop - and looking at the selection there to get a feel for what will work for you. Investigators and Researchers seem to develop a bond or affinity with their equipment. Strange as that sounds, it needs to "feel right" for you, and it also needs to be something you will be able to use easily and comfortably.
Video Camera- Primarily for documentation purposes and corroborative data. In the past eight years, our videographers have captured five incidents on video that may be due to paranormal activity. It is important to remember that every minute of video recorded must be then watched carefully and checked against photos and audio recorded at the time. A true labor of love, but highly rewarding when the effort pays off. It is best to get IR extenders for recording in low light situations.
At least one other like-minded individual - You should never go alone, for backup documentation as well as safety reasons

For More Advanced Detection and Documentation

Compass -Said to direct you towards spirits, and is supposed to spin when you enter the energy field of the spirit. I have not had much luck with a compass as a detection device, but historically it is a favorite.
Pendulums -
a pendulum is an object suspended from a string or a chain. Pendulums can be crystals, metal, or wood. Each user develops his or her own relationship with their pendulum. You will be able to determine, from the motion the pendulum makes, whether or not a spirit is present. For some people it spins, for some it swings back and forth, for others it moves in a circular pattern. I have had some dubious success with these. If you have worked with pendulums, and feel comfortable with them, use one.
Dowsing Rods -
Dowsing rods can be L-shaped and made of lightweight metal, or they can be a Y-shaped tree branch. The L-shaped metallic rods are what you use to detect ghosts. Dowsing has been around for ages. People dowse to find water, metal, dead bodies, and energy or ley lines. We have used them to locate spirit energy. The rods are held in the hands in front of the dowser. The rods will begin to swing and move toward a certain direction. While you are dowsing, you must concentrate on what it is you are hoping to find. When you locate the energy, the rods will cross. You can buy rods, or make them from coat hangers. I have had some success with this method. it takes a great deal of practice. I also know that not everyone is successful with dowsing. If this method works for you, use it! Y-rod dowsing - if you want to try the Y-rod, it should be made of a flexible tree branch. Hold the top of the Y (the handles) loosely. Begin walking and concentrating on what you want to find. The rod will tug you towards a direction. Follow it. When it reaches the source, the rod will bend downwards, or vibrate strongly. Again, this method does require a certain amount of practice and patience.
EMF Field Meters -
The theory is that the presence of a spirit can be detected because spirits disrupt the electromagnetic field. These are good because they give you recordable evidence that something unusual occurred. Always try to find a natural reason for the disruption before you assume it is a ghost. Take note of appliances, electrical outlets. By far, the best thing to come out lately is the Mel Meter. It is an EMF meter and ambient temperature reader and red light flashlight all in one! If you can only buy one piece of equipment, buy this!
Tri Field Meter -
The TriField Meter is the only EMF meter which offers magnetic, electric, and radio/microwave detection in one package. This meter combines all these unique features with affordable pricing for fast, reliable measurements of electromagnetic pollution: Continuous sampling analog readout; Omni-directional electric & magnetic sensitivity; Two separate scales for magnetic field readings. This meter will measure naturally occurring EMFs.Everyone should have one of these meters to see what they are being exposed to daily, even if they aren't paranormal investigators.
Night Vision Equipment, Thermal Imagers - I have heard of fabulous results with these, but I have yet to see any myself. Especially with Thermal Imagers,caution is necessary die to a lack of depth of field in the resulting image. Even if you pick something up on it, you have no way of knowing where it is in the field. These also send out a signal which bounces off a surface and returns to the device for interpretation.
Thermal Scanner -
These are devices used for recording the temperature of a surface area. They may enable us to record the temperature of the infamous "cold spot". care must be taken in the use of these. The device sends out an infra red beam to record the temperature on a specific surface. CAUTION You must guard against recording something that you don't want to record, like the sky or a windowpane in winter. Additionally, be aware that these record a SURFACE temperature. They do not take the ambient air temperature of an area. They cannot be used to detect "cold spots" in the middle of a room. They will only record the temperature of the first solid object the beam contacts. You can sometimes find them on E-bay. I got one from there, and it works great!
Ambient Temperature and Humidity - Much better for getting a reading on a temperature changes, but bear in mind the limitations of the device esepcially with regard to finding cold spots. Always remember there is a range for the sensor. Also make sure you know how much time is needed to get an accurate reading of the area you are in. This is a stationery unit. It also measures humidity, and this base can link up with up to four remote units. By switching through the channels you can monitor the temperature and humidity from one base location.
Motion Detectors -
These may be used for securing the perimeter of an area under investigation. I have also seen them used attached to video cameras left to record in an area. They can be used alone to detect motion in a room. Obviously, the detector would need to have an audible alarm in order for it to have any value as far as documentation. We use these motion detectors in our investigations: The GE Wireless MOTION DETECTOR .
K-2 Meters -
The K2 EMF meter is basically a crappy EMF detector. In theory, the K2 meter uses lights to indicate the energy instead of a needle, flashing and then finally staying lit at the level found with the meter. It does not give a specific number, just a range, so it is useless for recording shifts in EMF. In theory, when the K2 meter is on, you can ask a question from the spirits, asking them to respond with 'flash once for no, twice for yes', or a similar method. If you get a response when setting up this method and it works, then continue on with further questions that can be answered in a yes or no form.In addition to the following caution - me must regrettably report that due to flaws in the design of the K-2 meters, it is absolutely useless and has no place in responsible investigationg. Here is a short list of the electronic devices that cause it to react: led flashlight switch, digital camera on/off, cell phone, sangean hack on/off, laptop on/ff, IR webcams on/off. There are more things that cause it to give a false positive, but you get the idea. Again, we have found after one year of field testing that the design of this meter has too many flaws that make it an unreliable instrument for investigating the paranormal.

The Truth

• The truth is that we simply don't know what ghosts are composed of or what enables them to appear at some times and not at others. Many researchers are working on the answer.
• I have often advanced the theory that we are attempting to evaluate these things with equipment that is designed to evaluate objects that exist in our 3 dimensions.
• If ghosts exist outside the third dimension, then it stands to reason that these tools will be ineffective at best for studying them! I liken this dilemma to attempting to render a three dimensional object on a two dimensional surface (paper). You just can't accurately represent it!
• Another truth is that there are some people out there that fake ghost photos,encounters, etc. Maybe they like the challenge of fooling people, maybe they want attention, or maybe they are mentally ill and out of touch with reality. These people do serious damage to our research!
• Those of us who are serious researchers would never fake any piece of evidence, because we know that these events do occur as we describe them. We know that ghosts exist. We know that they can be recorded on tape and film. If we "fake" evidence, that would be an admission that we believe that they cannot be documented.