Transcript Central Unit Detection Unit

Final Presentation
Glass Break Detection Team
04-19-11
Team Members
Dennis Narcisse
Pic 24 Programming
Synapse Programming
Matthew Marsh
Signal Processing
Hardware Implementation
PCB Modifications
Christian East
Mark Lynn
Opamp Configuration
Signal Processing
Enclosure Design
Technical Documentation
PCB Design
Enclosure Design
Advisor
Dr. Raymond Winton
Advisor
MOS Devices, RFIC, and ASIC
Overview
 Introduction
 Problem Statement
 Solution
 Constraints
 Technical
 Practical
 SD1 Prototype
 SD2 Prototype Improvements
 PCB Design
 Enclosure Design
 Final Product Testing
Introduction
 Glass Break Detection System (GBDS) is an
alarm system that detects the frequency of
breaking glass
 Consist of a central unit and multiple
detection units
 System communicates wirelessly among all
units
Problem
 Current glass break alarms operate:
 as stand alone units
 hardwired to a central unit
 High cost for complicated designs
Solution
 Use low power wireless technology
 Central unit communicates to all detection
units
 Simplified design to lower overall cost
Technical Constraints
Name
Description
Range
The detection unit must detect glass breaking
up to 25 feet.
Accuracy
The detection unit must detect the noise
frequency emitted by the breaking of glass to
prevent false alarms from normal household
sounds.
Supply Voltage
The detection units must be battery powered.
The central unit must be wall powered.
Transmission Distance
Central and detection units must be able to
wirelessly communicate within a 33 to 246-ft
range.
Display
The central unit must have a display screen that
is easily read.
Practical Constraints
Practical Constraints
 Manufacturability
 The GBDS must be simple in its design
Prototyping Design
SD2 Improvements
 Added Pic24FJ64GA002
 Added Gain Amplifier after low-pass
and high-pass filters.
 Added Voltage Comparator
SD2 Improvements
 Added the Pic24FJ
 Faster wake up time than Synapse
 Low power microcontroller
 Functions of the Pic24FJ
 Interfaced with voltage comparator
 Handles ADC conversions
 Communicates with Synapse
SD2 Improvements
 High and Low Pass Gain Amplifiers
 43 times amplifier for greater accuracy
 Amplified Vmax to be easily read by the microcontroller
SD2 Improvements
 LM 339N Voltage Comparator
 Low power
 Compares AC voltage from low-pass filter to a DC
reference voltage
 Used to wake Pic24FJ
Central Unit
Detection Unit
Detection Unit Schematic
Central Unit Schematic
PCB Boards
Central Unit
Detection Unit
Central Unit PCB
Detection Unit PCB
Enclosure
 CANTEX
Size: 4 x 4 x 2 Junction Box
Cost: $4.30/box
Size: 6 x 6 x 4 Junction Box
Cost: $11.62/box
Enclosure Modifications
 Central Unit
 Precision cut for the LCD screen
 Hole punches for buttons
 Hole punch for LED
Enclosure Modifications
 Detection Unit
 Buzzer cuts
 Microphone cut
Final Product Testing
 Microphone Audible Range
Range (ft)
Thud Level (V)
Glass Level (mV)
10
2.3
800
15
1.7
580
25
1.3
340
Final Product Testing
 Low Pass Gain Amplifier
Final Product Testing
 High Pass Filter Amplifier
Final Product Testing
 Changes in Sensing Block
Old Voltage
New Voltage
Old ADC New ADC
High Pass
650 mV
340 mV
200
Low Pass
1.62 V
1.3 V
106
Final Product Testing
 Synapse Wireless Transmission Distance
 Well above our technical
constraint of 250 ft.
Final Product Testing
 Battery Life
 Calculated 41 months
 Current draw during normal operation is 365 uA
Production Cost
Central Unit
Detection Unit
Parts
$53.14
$54.48
PCB
$19.00
$28.90
Assembly
$0
$0
Packaging
$11.62
$4.30
Final Cost
$83.76
87.68
Final Product Testing
References
Questions