Reference design for smoke and fire detector

Analog Devices CN0537 Reference Design for UL-217 Smoke Detector is developed to demonstrate the use of the ADPD188BI Integrated Optical Module in a smoke/fire detection application. The ADPD188BI optical module is a comprehensive photometric system specially created for smoke detection applications. Using the device in place of traditional, discrete smoke detector circuits considerably simplifies the design as the optoelectronics (consisting of two LEDs and two photodetectors), and the AFE are already integrated into the package.

The reference design makes use of the EVAL-CN0537-ARDZ evaluation board. This board features a pre-mounted ADPD188BI module, contained in a proprietary smoke chamber that is particularly created to satisfy device and industry demands. The internal geometry of this smoke chamber provides for the highest SNR readings and, therefore, optimal PTR values for the ADPD188BI.

When combined with the EVAL-ADICUP3029 development platform, the evaluation board can be employed to create a reference design for a smoke/fire detector circuit compliant with the ANSI/UL-217 Standard for Smoke Alarms. The standard incorporates criteria to reduce nuisance alarms and address smoke characteristics between fast-moving and smouldering fires, significantly increasing accuracy and safety.

As battery-powered devices are a common use case for smoke detectors, the reference design minimises data needed from the sensor and the number of computations per alarm determination. This design enables the ADPD188BI to output less data, thereby conserving power and decreasing consumption cycles in the microcontroller, yet still meeting the strict UL-217 specifications.