Can things in one’s household(e.g. lightings, TVs, refrigerators) help people to become more healthy? Conventional health promoting products, such as activity trackers, provide health interventions to encourage health behavior change. However, these products provide a pre-fabricated solutions for desired behavior, often dismissing the personalized needs. Contrary to proposing automated solutions for target behavior, recent works investigate the creation of user-driven solutions for effective behavior change. With the growing market of Do-it-yourself(DIY) styles in IoT products, this study attempts to apply DIY methods for creating personalized and precise health behavior change interventions. In this study, we will propose a DIY IoT intervention design tool for users to develop their own health interventions by exploring how people assemble interactions with multiple IoT devices.