Most products are developed while adapting to requirements from industrial production and logistics. To break that trend and design for people, we suggest focusing on those who put the strongest demands on the final solution. They cannot compensate for bad design solutions and are thereby, like sniffing dogs, guiding designers to meet peoples' needs. We always use a combination of empathic modelling and involvement of people with reduced functions to find new solutions to the problems a product is supposed to solve. We have used this method in the teaching of Universal design at different universities for more than ten years. The students find the exercises to be a very entertaining eye-opener leading to development of empathy for human diversity all while the level of innovation in their design work increase. To constantly make design students understand barriers that can occur due to bad design solutions we utilize a toolbox simulating different kinds of functional ability. It also includes a handbook that describes workshops, evaluation methods and design processes that can be performed using the tools. The goal is to guide efficient, innovative and inclusive design processes. By simulating diversity among people, the designer can interpret the needs of different users and use that as a starting point and for evaluating design solutions during the creative process.