Carefully insert the flat end of the spudger into the seam on the top side of the device. Carefully twist the spudger to open the device. Repeat this step at incremental locations around the seam of the device until the two case halves separate.
Before completely separating the two halves, separate the case from the battery compartment cover, pulling the case apart. Take care not to break the plastic hinge as the battery compartment cover is removed.