As the result of the co-operation between researchers from Portuguese and Spanish institutions, several projects of experimental development of instrumentation have been carried out on the last years. In this paper, we present a new concept of a portable digital data logger for a seismic station, with the possibility to use until 12 channels and other type of sensors. In this first phase of the project, the result was a 3-channel portable digital seismic station with an excellent autonomy of registry and a reasonable consumption of energy. For its construction, seismic instrumentation systems with diverse functions were integrated altogether with electronic techniques for response extension of seismometers.