Smart Thumper is an affordable stiffness measuring mechanism that can be used as one of the tools to ultimately ensure the sound structure design and safe building constructions. In the forest products industry, the use of smartphones has increased. There are needs in the market to measure certain properties such as stiffness of wood materials. Devices currently available in the market for consumers are unaffordable and unpractical. Thus, we developed a smartphone application (App) that can measure stiffness.