Deployed in franchised fast food operations such as KFC, the system uses wireless sensors to automatically detect air quality and activate the ventilation system as required.

Its reliability and proven ability to dramatically lower electricity bills for franchisee operations resulted in one major fast food chain mandating its use.

Our Brief

Create a smart air quality management system that:

  • Reduced extractor fan power consumption by automating exhaust venting activation.
  • Used real-time data from wireless sensors placed at strategic points around the kitchen.
  • Achieved greater than 99% reliability/up-time to avoid lost revenues caused by ventilation system failures.


This project posed unique challenges, including the following requirements:

  • System reliability - shall be at least as reliable as the ventilation fans and controllers (ie very high).
  • Custom antenna - must be able to reliably communicate with all peripherals 100% of the time in an environment with numerous metallic objects obstructing/reflecting RF signals.
  • Multi-point radio communications - system must integrate multiple radio devies all simulataneously transmitting.
  • Mechanical integration - devices must be able to integrate withe xisting mechanical systems easily.
  • Device pairing procedure - must be simple, reliable, robust, permanent.
  • Reliable system testing - must include a simple, reliable test feature.

The Solution

System components integrated in this solution included:

  • HopeRF RFM69HW 915MHz RF (Radio) Module
  • Hall Effect Sensor (used for device pairing)
  • STM32F105 ARM ® CortexT-M Microcontroller
  • I²C LED Driver
  • 20VAC/DC Power Supply
  • 240 VAC Input Transducers

System architecture

Device Logic