One of humanity's great problems is the excessive amount of waste generated worldwide; therefore, it is of vital importance not only to reduce it but also to transform it into new products. Approximately 50 % of the waste generated in cities is organic, which can be transformed into compost to give it added value. This paper presents the design of an embedded software system to control a smart home composter system. The development process of the proposed software is guided by a specific method for embedded systems, which combines the spiral method with prototypes' design; the process is divided into eleven stages. In particular, this paper presents the results of the first seven stages of the process.