SLAA351A April   2007  – November 2018 MSP430F2232 , MSP430F2232 , MSP430F2234 , MSP430F2234 , MSP430F2252 , MSP430F2252 , MSP430F2254 , MSP430F2254 , MSP430F2272 , MSP430F2272 , MSP430F2274 , MSP430F2274

 

  1.   A Simple Glass-Breakage Detector Using an MSP430™ MCU
    1.     Trademarks
    2. 1 Introduction
    3. 2 Hardware Description
      1. 2.1 Device Specifications
      2. 2.2 Power Supply
      3. 2.3 Microphone
      4. 2.4 LED and Buzzer Alert
      5. 2.5 Interface to CC1100 or CC2500 Devices
      6. 2.6 Operational Amplifiers (OAs)
      7. 2.7 Internal Very-Low-Power Oscillator (VLO)
      8. 2.8 JTAG Interface
      9. 2.9 Current Consumption
    4. 3 Software Description
      1. 3.1 Initialization Routine
      2. 3.2 Timer_A
      3. 3.3 ADC10
      4. 3.4 Signal Analysis
        1. 3.4.1 First Stage of Processing
          1. 3.4.1.1 Signal Averaging, Peak Detection, and Zero Crossings
          2. 3.4.1.2 High-Pass Filtering
        2. 3.4.2 Second Stage of Processing
          1. 3.4.2.1 Frequency Composition Ratio
          2. 3.4.2.2 Peak and Zero-Crossing Count
          3. 3.4.2.3 Glass-Breakage Detect
    5. 4 Hardware Schematic
    6. 5 Test Setup
    7. 6 References
  2.   Revision History

3.4.1 First Stage of Processing

The first stage of processing is done every sample once a sound event has been detected. Figure 8 shows a summary of the operations for this processing.

flowchart_first_stage_analysis_laa351.gifFigure 8. First Stage Signal Analysis Flowchart