This whole article is a bit odd. Not only do they have the heartbeat theory back to front....but everywhere else I've read the wedding ring test it says that circular motion is for a girl & pendulum (backwards & forwards) means boy. (looking good Shel...not too long to wait now....but I'm really feeling 'girl' for you!)
I tried the wedding ring thing....holding it over my own belly whilst I lay down (I've heard its better if someone else holds the string or hair) & it kind of did half turns so I guess that's not really one thing or the other! Gotta love the old wives tales!!