Volumetric 3D ultrasound captures a region of interest more completely than cross-sectional 2D imaging, but 3D implementation has been limited. Mechanical wobbler and matrix-array probes can do 3D imaging, but these probes tend to be bulky and/or expensive, and precise orientation of the image with respect to the patient is not measured. In this work, we present a method of acquiring volumetric 3D ultrasound images with known patient orientation by utilizing a low-cost sensor. This method enables 3D imaging with any 2D imaging probe; this versatile and practical approach may increase the clinical utilization of 3D ultrasound.