Abstract:

Mobile tablets with capacitive multi-touch screens (tablets hereafter) have become popular as book readers and Internet access devices. It can be expected that tablets can be used as intellectual tools for children due to interaction with digital information via not only his/her fingers but also easy-to-make physical objects. In this paper, we introduce the potential of a tangible user interface (TUI) as an intellectual training tool designed to control digital information on a tablet via physical objects with multiple conductive points; no electronic components such as microcomputers, electronic circuits or batteries are needed in the physical objects.
The proposed interface has the following two advantages; a wide variety of software in e-learning, and children’s experiences of using their hand to make and operate physical objects. Since this interface can be controlled using physical objects easily made from everyday materials such as wood, paper, plastic, and metal film, children can brush up on practical and creative skills via making physical objects.
When intellectual training tools are to be used at home, it must convenient for children to pick up the tools from the predefined place at home and put the tools away in the place. The simplicity of this interface's system structure enables easy transportation and setup. Some TUIs that use external devices such as cameras or infrared sensors are not practical due to their numerous cables; they are inconvenient for children to setup and use.
When the physical objects with conductive points touch the capacitive multi-touch screen, the tablet can identify the object via a unique code pattern made by the points. Users can complete a task by using multiple physical objects in sequence. For example, if children are to learn the basic shapes, physical objects can be used in a matching activity where each shape shown on the tablet corresponds to a different physical object. The tablet can also calculate the representative position and angle of the physical object from the positions of the conductive points. For example, a ring object can be made to act as a telescope or microscope. Rotating the ring on an image can yield a virtual three dimensional space. Thus, functions of these devices that are normally accessible only in a science museum or school can become available at home.
The accuracy of detecting the position of each conductive point is critical in realizing attractive applications. We evaluated how the conductivity, size, and separation of the conductive points altered the accuracy of position detection. The results show that highly conductive materials should be used as the contact points. A commercial iPad detected all points over 3mm x 3mm but decreasing the point separation lowers the rate of detecting each point. In the case of the iPad, it is difficult to use physical objects with small touch areas but ring objects can be developed to act as magnifying glasses to solve this problem.

Keywords:

E-leaning, Mobile tablet, Physical objects, Conductive points.