What are drum triggers?

drum-trigger0kitMost of us cannot differentiate between an acoustic and electronic drum. My daughter put the same question to me and I could not explain to her.  She told me that an acoustic drum is made of wood or other materials while an electronic drum is made of electronic components.

Now devices have been developed to make an acoustic drum into an electronic one. Drum triggers are used for this purposes.

Drum triggers sense the vibration and pass it on to modules.