As mentioned previously, one type of AR technologies includes a head-mounted display and/or an additional backpack with computer
equipment. The cumbersome and expensive design could cause problems such as discomfort and poor depth perception (Kerawalla et al.,
2006). To avoid these problems, current development of AR systems adopts portable technologies that are less obtrusive and enhance
a sense of immersion and presence. Yet, these systems integrate several hardware and software devices and lead to issues like interfacing
between multiple devices (Klopfer&Squire, 2008) and stability of the devices (Dunleavy et al., 2009; Squire&Jan, 2007). Withoutwell-design
interfaces or protocols to guide students’ actions, students could have difficulties in interpreting the clues in the devices and the real-world
environment, recognizing the information flow from one device to another, and navigating between fantasy and reality (Squire & Jan, 2007).