Bioelectric potentials provide an intuitive source of control in human-machine interfaces. In this work an open source low-cost system for bioelectric signals acquisition and processing was developed. A single module can acquire up to 8 differential or single-ended channels, and several modules can be daisy-chained together. Opto-isolated USB communication was included in the design to interface safely with a personal computer. Embedded digital processing was used for float conversion and filtering. The high-level software was implemented as a complementary part of BioPatRec, an existing open source project. Source files for the PCB, firmware, and high-level software are available online (GitHub: ADS_BP). This integration provides a low-cost, open source and complete system for research on intuitive myoelectric control.