Multi-Zone Reaction Trainer
4-zone physical reflex station with serial latency auto-calibration
System Overview & Objective
Engineered an interactive reflex testing station using an Arduino microcontroller and four ultrasonic distance sensors covering independent spatial zones. The web interface streams high-frequency telemetry over the Web Serial API. To prevent serial buffer jitter from distorting millisecond reaction timing, the dashboard and firmware perform an 8-sample timestamp handshake on connect to estimate link transit delay, producing latency-compensated reaction metrics.
Verified Empirical Benchmark & Metrics
View markdown report on GitHubObserved serial link delay range: 23–40 ms baseline reduced to ±1.8 ms residual jitter post-calibration (Empirically benchmarked on Windows 11 / Chrome 140 with Arduino Uno over 115,200 baud USB serial, n = 100 sample cycles; documented in docs/benchmark-2026-09.md).
Execution Pipeline & Signal Flow
Technical Challenge & Engineering Solution
Direct serial communication introduces variable transit jitter across USB host polling intervals (23–40 ms baseline range). Solved by establishing a baseline offset via an 8-cycle timestamped ping-pong handshake between the browser and firmware at session startup.
Architecture Specification
Arduino microcontroller polling 4x HC-SR04 ultrasonic sensors -> Formatted serial stream with ping/echo timing -> Web Serial API stream reader -> Jitter-compensated canvas reflex telemetry dashboard.
Key Highlights & Technical Deliverables
- Physical 4-zone spatial trigger detection with ultrasonic distance sensors
- Dynamic hardware-software latency auto-calibration handshake
- Real-time millisecond-precision reaction telemetry and charting
- Zero-dependency lightweight serial driver running in modern browsers