An exemplary CMOS image sensor comprises a plurality of pixels arranged in an array. A docking cradle or external adapter can receive the electronic device and cover. The first light receiving surface receives light that is emitted from the LED light source in a direction slanted with respect to the light emitting surface, and takes a concave surface configured such that a distance of the first light receiving surface to the light emitting surface increases from one end to the other end of the lens. Thus, any smart card is effectively transformed via the use of the MSB into an ordinary magnetic finance card and is admissible for use by any conventional magnetic card reader.