Quick deployment of open-source hardware and software for a dual-channel biosignal recorder

Access to a prototype during R&D can play a crucial role in early identification of the weaknesses in the design. Under circumstances that a particular commercial subsystem with the exact required specific features is unavailable, the realization of such a prototype can be delayed. In this paper, an example of rapid prototyping for a dual-channel biosignal data acquisition system based on the open-source concept is described. The selected biosignal is the finger photoplethysmogram. Except for Matlab, all other software components are open-source. The hardware design of the optical sensor utilized to record the signals is also open-source, making the system extremely affordable with the advantage of flexibility and customization. Precise timing of the samples allows for proper alignment and delay estimation between the acquired traces, useful in arterial stiffness studies. Although the results presented concern only two channels, the system has the ability to be expanded to six channels. Further possible expansions include the addition of custom filtering, on-board data compression and advanced GUI.