Techniques are described for measuring angle and/or orientation of a rear drivable section (e.g., a trailer unit of a semi-trailer truck) relative to a front drivable section (e.g., a tractor unit of the semi-trailer truck) using an example rotary encoder assembly. The example rotary encoder assembly comprises a base surface; a housing that includes a second end that is connected to the base surface and a first end that is at least partially open and is coupled to a housing cap; and a rotary encoder that is located in the housing in between the base surface and the housing cap, where the rotary encoder includes a rotatable shaft that protrudes from a first hole located in the housing cap, and where a top of the rotatable shaft located away from the rotary encoder is coupled to magnet(s).