We report a low cost and extrinsic Fabry-Perot interferometer-based optical fiber displacement sensor with a wide dynamic range, up to 2.0 cm, and 0.270 µm resolution. The fundamental design principle includes an inclined mirror, mounted on a translational stage, that combines with the end face of a single mode fiber to form a Fabry-Perot cavity. The user-configurable triangle geometry-based displacement transfer mechanism makes the sensor capable of measuring a wide displacement range. A fiber ceramic ferrule is used to support and orient the optical fiber, and a metal shell is used to package and protect the principal sensor elements. The novel sensor was employed to monitor shrinkage during the drying/curing stage of a square brick of mortar. The robust and easy-to-manufacture sensor can be easily commercialized and has great potential for applications in the chemical-oil industry, construction industry, and other industries with harsh environments.