Here's a list of some basic tools you can use. There are so many more and the list seems to grow daily.
We're all just playing it by ear when it comes to hunting ghosts. The coolest part about is we all contribute some way or another when it comes to equipment.
Everyone has their own technique when hunting and using tools of the trade but here are a list to start with....
Ghost Hunting Equipment
Camera: 35mm camera with black and white film and/or infrared film. Video or camcorders are also very good and should be used. Use brand new tapes. Don't use an old tape and tape over something. Have all the film developed by experts. Don't forget tri-pods!
Night Vision Equipment: Night Vision scopes can be very useful. You can also get cheap adapters that will attach the scopes to video cameras for about $30. Night Vision Equipment can be expensive but it is getting more price reasonable. Expect to pay between $250-$4000. You can get some good scopes in the $300 range that work very good on video equipment.
Tape Recorder: A good tape recorder and an external static free microphone should be in use at all times in the ghost hunt. Even if you don't hear anything during the hunt rewind the tape and play it back. Spirit voices have been known to be heard on tape later after review. This is referred to as, EVP, Electronic Voice Phenomena. Again, use brand new tapes when recording.
Flash Lights: Always have bright flash lights (usually 3 or 4) and extra batteries. Sometimes candles may be used but don't count on them staying lit.
A Notebook and pens/pencils: Notebook is a good way to keep notes, records of time or a journal of events.
EMF Detector: These are great! EMF Detectors can pick up electronic fields over different frequencies. Where there are ghosts there are usually disruptions in the electronic field. They are relatively cheap ranging from $24 to $130. You should try to get a hold of one or more of these for all field work. As a guide line each person in your group should have one on hand.
Thermometer: A good thermometer can detect changes in room temperature quickly. It's best to use the old fashion mercury filled, red line, thermometers. They have electronic thermometers but in ghost cases where electromagnetic forces have been reported they might fail right when you need them.
Compass: Great for navigation if you know how to use one and also great for picking up those electromagnetic forces. A compass will react to any magnetic or electrical stimulus that is out of the ordinary. Same rules apply here, try not to use the electronic compass's. Stick to the simple boy scout, needle points North version.
Ghost Catcher: (also called, a Spirit Wind Chime) The idea here is that the spirit will pass by and cause the ghost catcher to chime much like a wind chime does in the wind. You can use the wind chime that you get in the stores, however, try to get the ones made of the lightest material. You don't want the arms to be too heavy. For obvious reasons these will not be affective outside or in any area where a breeze or wind is blowing.
You can make Ghost Catchers yourself. Take about 8 to 10 very thin strips of metal (about one inch wide and about 6 to 8 inches long). Put a hole in one end of each strip. Tie separate strings to each strip. Leave about 6 inches of slack in the string and tie the other end of the strings to a pole or something that keeps the strips hanging down. Tie them about one half inch apart on the pole. The strips shouldn't touch each other but shouldn't be very far apart either. Hang the pole from the ceiling or in a doorway. I know that some people paint the strips with glowing paint to make them easier to see at night or in the dark. Any variation on a wind chime will work. For the best results make several ghost catchers and put them at different spots throughout a house.
Infrared Thermal Scanner: These saves on infrared film and time by accurately pin pointing the cold spots. These scanners are excellent to use in outside investigations. Price range is around $300 to $500. This is not something that you must have, but if you can afford, it give it a try.
Air Ion Counter: Measures positive and negative Ions in the air. This little add-on is a great instrument to have for use in the field. The price is high, around $400 - $600.
Headset Communicators: When you have a team of three or more people headset communicators are a great idea for staying in contact when spread out. You can use the hand held walkie talkies but the headset frees up your hands for holding cameras etc. They will run in the price range of $30 to $80 a piece. I've seen good sets that work up to a distance of 100 yards for 40 bucks.
Spot Lights: Small battery powered spot lights really help at night when it comes to setting up and taking down cameras and other equipment. They can also be used for safety and to get a better view of the surrounding terrain at night. Get the lights that sit on the ground but have swivels on the lights to set them to different angles. Plan on getting between 2 and 6 spot lights depending on your needs.
There are ton and tons of so many other devices.... Like divining rods, Franks box's ect... Even psychics. The sky is the limit.
You also might want to visit this site......The Ghost Hunters Bible
www.zerotime.com/storefront/ghosthunter/Hope this helps and good luck and happy hunting!