Currently, the study of electromyographic signals (EMG) has allowed the development of diverse applications in clinical and biomedical fields. For instance, EMG signals has served as inputs for different types of human-machine systems. However, the process for the acquisition of this type of biosignals presents some inconveniences associated with the degree of invasiveness, the use-convenience balance, and the range of portability. For this reason, in this study we designed and validated a wearable and portable system for the acquisition of surface Electromyography (sEMG) signals for the upper limbs. The design consisted of an adaptable arm-forearm cuff (not invasive), allowing different electrode distributions for signal acquisition. We tested our prototype with the OpenBCI board through several experimental protocols, obtaining high levels of ergonomy and signal quality. With this development we expect to the acquisition of EMG signals that could be integrated to different human-machine systems such as EMG prostheses.