I've used a pendulum a couple of times to help me make decisions. I find that when asking a yes answer, swings in a circle and when asking a no question it swings back and forth - I usually write yes or no on a piece of paper and then let my pendulum find it's own way to the answer and then let it do it's stuff. I don't use anything fancy, just a silver/Cubic Zirconia cross pendent and silver chain that I've had for some years, which I wear all the time. I believe that because it's something that I never hardly take off it captures my vibes and my emotions, especially during the really hard times and helps me see the way forward.
I've tried this with other chains and pendents but they've never felt right, and it seems that my cross doesn't like being worn by any other person. A friend of mine wore it to a party and when she gave it back to me she told me that it felt really weird and heavy, yet it felt fine to me.