We are in the process of preparing a teaching experiment on robotics in primary schools. In relation to this, we investigate in this paper whether it is possible to prepare teachers adequately to implement the intended pedagogy with the help of an in-service teacher education course that we developed. In view of the forthcoming teaching experiment, we were especially interested in the content and character of the knowledge, insights and attitudes of the teachers. We therefore capitalized on qualitative measures. We report how teachers developed the required knowledge and skills in three domains, i.e. subject matter knowledge, pedagogical knowledge, and pedagogical content knowledge. We examined whether teachers were able to accommodate the content knowledge, concepts and approaches we proposed, whether they developed a personalized version of pedagogical content knowledge, and whether they increased their pedagogic ability with respect to scaffolding pupils' learning of robotics. We draw some conclusions with regard to the professional development of primary school teachers in areas of science and technology with which they in general are unfamiliar.