To provide trustworthy cooperation and dynamic node addition in wireless sensor networks, access control is of great concern. Access control should be designed to be secure and efficient even under practical restrictions. Otherwise, theoretical results cannot be immediately applied to real environments. In this paper, we discuss that the recently proposed hash-chain based access control methods are not secure when practical restrictions are considered. We then propose two practical access control protocols, called PACPs. It is shown that PACPs are practically secure yet require less communication/computation costs than those of the previous methods.