User Guide

OpenSync is an open source synchronizer for particle image velocimetry (PIV) and other laboratory measurements that depend on coordinated timing. Cameras, pulsed illumination sources, and acquisition equipment must respond at known times for their measurements to be useful. OpenSync provides a shared timing reference and eight independently programmable output channels, allowing an experiment’s timing to be configured through a common device interface.

The project began with a practical barrier identified in the SDLC briefing and feasibility study: commercial synchronizers can represent a substantial cost for laboratories with limited funding. Simple custom microcontroller solutions can reduce that cost, but often offer limited timing flexibility or require firmware changes whenever an experiment’s timing changes. OpenSync exists to make a configurable synchronizer more accessible while keeping its hardware and software available for inspection, modification, and reuse.

The design uses the Raspberry Pi RP2350’s programmable input/output (PIO) state machines to handle timing independently of the main processor’s command handling. The internal rate timer and individual output sequencers provide configurable timing, synchronization, triggering, and gating. A USB SCPI interface, Python library, and browser application let users change settings without rewriting the timing firmware. The emphasis is on an affordable, constructible device that supports a broad range of PIV measurements, rather than reproducing every feature of a commercial instrument.

Hardware, firmware, and software

• Hardware Guide
• Firmware Guide
• Software Guide

The Hardware Guide is reserved for building the physical device. The Firmware Guide explains the code running on it, including release installation and source compilation. The Software Guide covers Python, the PWA, and the basic-operation notebooks.

Project background

This overview draws on the project’s requirements briefing, feasibility study, and firmware revision planning. These SDLC documents record the design’s evolution; early proposed channel counts and configurations may differ from the current device.