Fly-Scan Trigger System

Instead of the classic move–stop–measure loop, this system measures on the fly: a rotation stage sweeps at constant velocity while its controller emits a hardware trigger at exact angular intervals, and those edges clock a National Instruments DAQ so each sample lands at a known angle. The result is dramatically faster angle-resolved measurements with no settling time.

The subtle engineering is in trust: when the angle axis is derived from trigger counting, a single missed or phantom edge silently shifts every subsequent point. I root-caused that fragility and designed the hardening plan — trigger-count reconciliation against expected edges, an averaged acquisition mode where the DAQ free-runs and a counter tags edge positions for post-scan alignment, deterministic hardware start-triggering, and validation that models the detector’s gain-dependent bandwidth instead of just the stage’s limits. Also the fail-safe rule that shows up everywhere in my work: refuse loudly rather than silently zero-fill when a calibration input is out of range.

Python, Zaber motion control, NI-DAQmx, photodiode detection. Source is private.