Automated Rotating Cat Litter Box

/Problem

Existing automated litter boxes either misfire (rotating while occupied) or fail to detect smaller animals. The system required a deterministic detection stack robust to vibration, lighting, and litter dust — without relying on expensive vision systems.

/Approach

1. 01Specified a multi-sensor fusion stack: HX711 load cells for mass, an IR break-beam array for occupancy, and Hall-effect sensors for drum position.
2. 02Implemented an ESP32-based firmware state machine (IDLE → OCCUPIED → SETTLE → CLEAN → DUMP) with debounced transitions and watchdog safety timers.
3. 03Developed a calibration procedure using reference weights and statistical noise characterization (σ, drift, hysteresis) for each sensor.
4. 04Tuned detection thresholds with logged real-world data to achieve high true-positive and near-zero false-trigger rates.

/Results

• False-trigger rate driven to <1% across 200+ test cycles.
• Detection latency < 400 ms from entry to OCCUPIED state.
• Achieved BOM within target budget; design documented for manufacturability.