An opto-mechanical micro-switch has a micromachined structure fabricated from a single silicon substrate. The micromachined structure includes an inner frame connected by a pair of beams to an outer frame. The beams define an axis of rotation around which the inner frame rotates relative to the outer frame. Flat walls are formed on the inner frame by an anisotropic etching process. When the inner frame rotates relative to the outer frame, the flat wall pivots into a vertical position to reflect or impede light passing from a light source to a light receiver. During fabrication, etch-stop material is selectively deposited in predefined regions of the single silicon substrate, and then a masking layer is formed and patterned. The anisotropic etching process is then performed through openings in the masking layer to form the inner frame and the outer frame. The etch-stop material prevents etching in the predefined regions that are located between the inner and outer frames, thereby forming the beams. In one embodiment, Permalloy regions are formed on the inner frame prior to the anisotropic etching process. These Permalloy regions are subsequently utilized as part of a drive motor to rotate the inner frame relative to the outer frame.