At the heart of social needs for SW education is the computational thinking. We need a way to define and evaluate the computational thinking ability based on the 2015 curriculum. In this study, we focused on how to apply, visualize, and evaluate computational thinking processes to achieve the goals of SW education. In particular, we propose an educational use of the task of developing IoT (Internet of Things) device using Arduino input / output computing systems and s4a (Scratch for Arduino). The proposal can be applied to various subjects, in visualizing and summarizing the process of computational thinking.