Minecraft item right/left click detection

Solution 1:

In the video you linked from sethbling, he is actually just detecting the snowballs that are thrown, as snowballs are throw able. He's not detecting right clicks.

If you want to detect when an item is right clicked, the simplest method is to have an armor stand teleported exactly to you, and when you click the item, it the item will actually be put in to the armor stand's hand, which can then be detected. Once that's detected, you give the player another item, and set the armor stand's hand to empty. Rinse and repeat.

More info and commands can be found in this video: