Gear train

Gears can be used to slow down, commutation, transmission and other mechanical mechanism.More tutorials please visit http://www.makeblock.com/ Our community: www.makeblock.com https://www.facebook.com/Makeblock?ref=br_tf https://twitter.com/Makeblock https://www.youtube.com/channel/UC8Du3ES62iGgeckG4W9jC9w