SLAA351A April 2007 – November 2018 MSP430F2232 , MSP430F2232 , MSP430F2234 , MSP430F2234 , MSP430F2252 , MSP430F2252 , MSP430F2254 , MSP430F2254 , MSP430F2272 , MSP430F2272 , MSP430F2274 , MSP430F2274
This application report describes a simple glass-breakage detector using the MSP430F2274 ultra-low-power microcontroller (MCU). The algorithm is based on the spectral analysis of a typical glass-breakage signal. The input signal spectrum, limited to a frequency of 20 kHz, is processed for a valid glass breakage. Various signal characteristics such as peak content, number of zero crossings, and frequency composition are analyzed. Real-time signal processing is achieved by implementing and using a low-order bireciprocal lattice wave digital filter (LWDF). A glass-breakage alert is indicated by an onboard buzzer and an LED. The entire setup is designed to operate at low power, allowing long battery life.
Related schematics and code source can be downloaded from www.ti.com/lit/zip/slaa351.
For more information, see A Simple Glass-Breakage Detector Reference Design and
A Robust Glass-Breakage Detector Reference Design.