Open Sync Board – An open-source tool for hardware synchronization of multimodal physiological sensor setups

The fusion of multimodal sensor data gains increasing importance in medical and psychological research. In particular, the analysis of multi-modal data contributes to a broader understanding of human well-being. When experimenting with different sensing modalities, precise synchronization of recorded data is a crucial problem that needs to be addressed. We have developed a hardware-based solution capable of synchronizing up to seven arbitrary measurement modalities. These modalities can be mounted to a PCB with various connectors to be either triggered synchronously or receive simultaneous synchronization signals. In the latter case, data can be aligned after the measurement. All PCB outputs are galvanically decoupled to avoid interference and ensure safe usage in human-centered research. In this project, we put particular emphasis on flexibility, high usability, and accuracy. Thus, different synchronization signal options are provided to suit short- as well as long-term measurements. Settings can be configured easily with an accompanying graphical user interface. Additionally, we ensured a high precision of the output signals is ensured with an estimated maximum delay of 125 μs between the output ports. This enables sub-sample synchronization accuracy for sensors with up to 8 kHz sampling rate.