What kind of tyre pressure sensor is it in the Octy?

There is no tyre pressure sensor as such, the TPMS works in conjunction with the abs wheel speed sensors and picks up a change in rolling resistance when a tyre deflates.

Edit: guy above me said it better.

Edited 14 April, 201511 yr by Gromle

Ah, great. So no need for expensive sensors when you change tyres.

Ah, great. So no need for expensive sensors when you change tyres.

Nope. Just Check the pressure in the tyres, press a button and you are good to go.