Within this paper, we present three human-robot interfaces using handheld device as mediator object between the human and the robot: a virtual keyboard interface on the iPhone, a gesture based interface on the iPhone too and a Wiimote based interface. These interfaces allow to show particular objects to a robot. They were designed to be ease- of-use, specially by non-expert users, and to span different metaphors of interaction. In order to compare them and study the impact of the metaphor on the interaction, we designed a user-study based on two obstacle courses. Each of the 25 participants performed two courses with two different interfaces (total of 100 trials). Although the three interfaces were rather equally efficient and all considered as satisfying by the participants, the iPhone gesture interface was largely preferred while the Wiimote was poorly chosen due to the impact of the chosen metaphor.