## 1 Introduction  
In recent years, the Internet of Things (IoT) has attracted much attention because of the provided functionalities that can advance humanity in terms of intelligence, automation, convenience, _etc.  
The IoT can change objects that are precisely unidentifiable into identifiable, recognized, interconnected intelligent objects based on the standard communication protocols, called Smart Objects. The IoT consists of a number of smart objects that are embedded with wired/wireless communication interfaces to communicate and interact with each other without human intervention. The basic concept of IoT is that various smart objects can be automatically linked into a network for interacting with humans through perception and networking technologies. Smart objects in the IoT have the ability to send information through the Internet to provide the interaction among multiple things and people. For example, a smart power meter can get information with regard to energy usage from various electrical devices. Afterward, the smart power meter sends information wirelessly to the access point and the information is further forwarded to user devices through the Internet.  
The development of IoT technologies can support a variety of applications, including the intelligent power grid [1; 2; 3; 4], intelligent transportation [5; 6], intelligent medicine and healthcare [7; 8; 9; 10], intelligent art [11; 12], intelligent logistics [13; 14], intelligent environmental monitoring [15; 16], smart life [17; 18; 19; 20], _etc._ In a smart home context, numerous smart objects need to use wireless communications due to the requirements of supporting mobile applications and maintaining neat living space. So far, numerous wireless technologies had been integrated and designed for various purposes, however, most applications of smart home neglect a well-designed wireless technology--ZigBee. ZigBee is an efficient short-range wireless technology in terms of power consumption and deployment scalability [21]. It is a low-power wireless transmission protocol, providing a suitable data rate for control and monitoring purposes. ZigBee Alliance [22] was formed in 1998 by Honeywell Corporation, whose main task is using IEEE 802.15.4 low-power wireless network protocols as the basis to develop the specification of IoT applications. However, most of the developed devices can only communicate with those devices that are also embedded with the ZigBee module.  
A few recent papers [23; 24; 25] aimed to develop an ambient intelligence system. However, most of them just proposed an architecture and pointed out some challenges in smart home. Different from the studies [23; 24; 25], this paper pursues the goal of designing and implementing an IoT Access Point (AP) through which wireless devices such as projectors, laptops, and smart phones are allowed to access the local area networks or Internet. After designing the working system in an access point, we implement the IoT AP that not only is suitable for convenient deployment in a smart home but also covers both the gateway and AP. That is, the proposed IoT AP saves the hardware cost and energy consumption, as compared with two independent devices--a gateway and an AP. In the implementation, the IoT AP can be used for some smart spaces to automatically control the traditional TV, the air condition, the smart meter, the sphygmomanometer, the smart phone, _etc._ The main contributions of this paper are itemized as follows.