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Day 25 - Hybrid Robustness & Coalescing

Summary

Enhanced the hybrid sensor driver with:

  • Global cooldown mechanism
  • Update coalescing
  • Detailed runtime metrics

What I Learned

  • Difference between event, update, and skip
  • How to implement global rate limiting
  • How to design trigger-aware update policies
  • Importance of observability in driver behavior

Key Improvements

  • Added min_update_interval_ms
  • Introduced skip counters
  • Refined update decision logic
  • Improved debug visibility

Observations

  • IRQ can generate many events but few updates
  • Polling provides stable fallback updates
  • Cooldown significantly reduces redundant work

Challenges

  • Designing clean separation between policy layers
  • Avoiding race conditions while adding logic
  • Making debug output meaningful

Takeaways

  • Not all triggers should result in updates
  • Rate limiting is essential in real systems
  • Debug metrics are critical for validation
  • Hybrid systems require careful tuning

Next Steps

  • Improve IRQ priority over polling
  • Introduce adaptive policies
  • Explore bus abstraction (I2C + SPI)