The pendulum is an ideal instrument for discovering objects of any kind. There are two kinds of searching methods: The triangulation and the pendulum pursuit:

Triangulation

The method of triangulation is used to determine the position of a certain object. You swing the pendulum at 2 different places, which should be in sufficient distance to each other.
 
Question: In which direction is the object in request? The pendulum indicates a direction from both points. The object in request is at the intersection of the two lines.

It works better, the more exactly you can imagine the object.

Pendulum pursuit

You begin with a question like in triangulation. The pendulum kicks in a certain direction. You follow the direction, repeating the question again and again and visualising the object, until the pendulums changes the direction. When you have reached the target, the pendulum normally changes from the direction announcement to a left-right oscillation or to circles, depending on whether and what was determined before.

Pendulum pursuit exercise

If you have acquainted yourself sufficiently with the pendulum, another person can hide an object which you should know well (e.g. a ring) in your flat. I wish you lot of fun while finding!