Event for pushing buttons

Hello,
I have learned some basics by watching the plugin programming tutorials by Torrent from WoopaGaming. Today I tried to code something small own, I wanted to code a small Plugin that broadcasts a text on a sign to the server by pushing a button beneath the sign.
I wanted to start with the more easy part, the part of the button push listener. I looked for an event that passes when a button is pushed, but I didn't find it. I only found the PlayerInteract event, but that is not what I am looking for. I want the event to pass when the button is "pushed", not "rightclicked". Understood?

I hope somebody can help me.

Hm, mabe it sounds a bit confusing. I just want to know if there is an extra event for pushing buttons, apart of the PlayerInteract event.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

OnRedstoneChange?

 

Thank you for your help, that is what I am looking for.
So I could finish my plugin today