DNA base detection is a vastly advancing technology to obtain the bases sequence in human genome thus allowing for recognition and medication of disease. Acquiring reliable, quick, and cheap DNA sequencing facilitates personalized medicine procedure where right medication will be given to patients. In this article, a semi-empirical model is presented for calculating electron transport properties for the z-shaped sensor to identify the DNA sequence. The z-shaped sensor is made of two metallic electrodes of zigzag graphene nanoribbon (ZGNR) connected through a semiconducting channel with a pore in the middle where DNA bases are translocated. The channel is made of armchair graphene nanoribbon (AGNR) which is semiconducting. Semi-empirical model and non-equilibrium Green's function are utilized to ananlyze the various electronic characteristics. The semi-empirical model used is an expansion of the extended Hückel technique with self-consistent Hartree potential. Using the non-equilibrium Green's function combined with self-consistent extended Hückel (NEGF+SC-EH), we show that each of the bases placed within the pore whose edge carbon atoms are passivated with nitrogen leads to a unique current. Several electronic properties are studied such as electrical current and transmission spectrum of DNA bases within the sensor's nanopore. These characteristics are investigated with modification of base orientation. Our study produced unique current for each of the DNA bases inside the pore.