My diploma's final year project was "Voice Operated Gear Shifting".
It consists of an electronic circuit and a prototype of constant mesh gearbox.
I had been used lead screw & nut mechanism to obtain the forward and backward motion. lead screw is rotated by motor which connected to electronic circuit which is programmed on the time basis i.e. the time required to travel from one gear to another gear.
when we say "one" the gear changes to one same as "two". this project was selected for Dipex 2014. we got a good feedback i.e nice concept..