Download Testing tool for sensor manufacturing

Outline
Introduction & Background
System Description & Diagram
Specifications
Design – Four Stages
Future Development
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Introduction
 In today’s business environment, the US sensor market is
expected to grow at an annual rate of 4.6%, to reach
approximate $7.6 billions by 2009.
 Increased sensor demand will bring an increase in
production and testing capacity.
 Our objective is to design a tool and establish its technical
requirements, in order to speed up the testing of sensors in
the manufacturing process.
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Background
 Sensor is a device that responds to a physical stimulus, such as
thermal energy, electromagnetic energy, acoustic energy,
pressure, or motion, by producing an electrical signal.
 Most sensors are electrical or electronic although other types
exists.
 Electrical voltage sensors vary in terms of performance,
specifications, optional features and environmental operating
conditions.
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System Description
 The system described will focus on testing electrical voltage
sensors and all tests are assumed to be done at room
temperature.
 The system will test newly built sensors and compare it against a
reference sensor known as a “good” sensor.
 The testing tool will lit a green light for a “Pass” unit and a red
light for a “Fail” unit.
 The system consists of four stages: differential stage, rectifier
stage, comparator stage, and selection stage.
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System Diagram
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Design
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1. Differential Block
Potentiometers are used to
simulate the sensors
Upper
POT
is
the
tested
sensor
Lower POT is the reference
sensor
Difference
between
two
sensors is amplified (Gain = 30)
The difference can be either
positive or negative
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2. Rectifier Block
The input to the rectifier
could either be positive or
negative.
The purpose of the rectifier is
to take the absolute value of the
input voltage.
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3. Comparator Block
The absolute value of the
difference is compared to the
threshold voltage.
The threshold voltage can be
adjusted according to our
specifications.
The output can either be
positive or negative.
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4. Selection Block (Pass)
If the input voltage is
negative, Q1 is cut-off, Q2 is in
the active region.
Green LED lights up which
indicates the sensor passed the
test.
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4. Selection Block (Fail)
If the input voltage is
negative, Q2 is cut-off, Q1 is in
the active region.
Red LED lights up which
indicates the sensor failed the
test.
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Selection Range
FAIL
PASS
FAIL
Note: above results are measured at 50% threshold (6V)
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Selection Range (2)
16
Output voltage
14
12
10
8
6
4
2
0
-2
Input voltage
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Future Development
 Develop the testing tool such that other types of sensors
can be tested.
 The testing tool can be made portable, so that it can be
used in different locations.
 Digital display can also be added for input and output
observations.
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References
 Belusov, Alex “Simple procedure test transducer” EDN, March 1,
1996, pg 144
 Frank Keys, “All Types of Sensors”, http://www-
sensors.com/sensors-applications.html
 Sensorsoft Corporation, “Real-time Contract and Voltage Sensor
Specifications’’, 2005-2006
 Wikipedia, Sept. 2006, http://en.wikipedia.org/wiki/Sensors
 Telecom Glossary 2K,
Feb.2001, http://www.atis.org/tg2k/_sensor.html
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