Lab 1 – Don’t Forget Me
Lab 1 – Don’t Forget Me: Product Description
Brandon Fields
CS411
Janet Brunelle
February 4, 2008
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Lab 1 – Don’t Forget Me
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Table of Contents
1
INTRODUCTION....................................................................................................................3
2
PRODUCT DESCRIPTION ....................................................................................................3
3
4
2.1
Key Product Features and Capabilities ........................................................................4
2.2
Major Components (Hardware/Software) ....................................................................5
2.3
Target Market/Customer Base .....................................................................................6
PRODUCT PROTOTYPE DESCRIPTION ............................................................................7
3.1
Prototype Functional Objectives ..................................................................................7
3.2
Prototype Architecture .................................................................................................9
3.3
Innovative Features ....................................................................................................11
3.4
Challenges and Risks .................................................................................................11
PROTOTYPE DEMONSTRATION DESCRIPTION ..........................................................12
GLOSSARY ..................................................................................................................................14
REFERENCES ..............................................................................................................................16
List of Figures
Figure 1. Major functional component diagram .............................................................................5
Figure 2. Phase 1 prototype major functional component diagram. ...............................................9
List of Tables
Table 1. Feature comparison between full product and prototype ................................................11
Lab 1 – Don’t Forget Me
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Lab 1 – Don’t Forget Me: Product Description
1
INTRODUCTION
As of last year at least 43 children died in cars while their parent or caregiver was away,
and each year the number of deaths increases. (KAC, 2007) Unfortunately it does not take long
for a car to become dangerously hot and endanger the life of a child inside. Modern cars do not
yet have the capability to determine when the conditions of its interior could pose a danger to its
passengers, nor do many vehicles have the ability to register that a child has been left inside.
The goal of the Don't Forget Me (DFM) system is to eliminate such instances of
unintentional child endangerment. By implementing a series of sensors that will determine if a
vehicles is occupied, the system can begin to take corrective action. A heartbeat sensing system
is one of the primary components; the data it collects is analyzed for a verifiable pattern.
Secondly, pressure sensors will be installed beneath the seats to determine if anyone is occupying
the vehicles. Once again the output of the sensors will checked by the accompanying software to
ensure it is a person and not an obstruction detected. There will also be careful monitoring of the
temperature inside the car. Since the temperature can rise to fatal levels in minutes, a high
temperature reading will initiate an aggressive check of the vehicle for persons who may be in
danger. This device is autonomous and does not require the activation of the car's operator. It
seeks to eliminate instances when one can let even important issues pass their attention.
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PRODUCT DESCRIPTION
This section describes in detail the manner in which the fully implemented DFM safety
system will run. Aside from a breakdown of the product and the intended customer, aspects such
as customer customization and reliability are also addressed.
Lab 1 – Don’t Forget Me
2.1
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Key Product Features and Capabilities
The DFM safety system is unique in that is utilizes an assortment of sensors to detect life
in a manner that has never before been implemented. While two or more sensors may be
sufficient to detect life, more would be necessary to reach a high degree of certainty. Each sensor
allows the software to incorporate a system of checks and balances to prevent against false
alarms or decision made on insufficient data. Likewise, the system will not be rendered useless
when one the sensor inevitably malfunctions (given the lifespan of any component in a vehicle
over an extended period of time).
Overall, the greatest strength of the DFM is the software developed to integrate each
hardware component into one homogenous system. Under the assumption that no two types of
sensors have the same accuracy, neither will they have the same priority. While a motion sensor
is effective at detecting movement it would not have the same accuracy as a heartbeat sensor
meant to analyze a heart’s rhythm. Therefore, it is prudent to grant a positive reading from the
heartbeat sensor higher priority than the result from a motion sensor. Moreover, a CO2 is even
less indicative of life given that the car is not airtight and the sensor may have a low level of
precision. As a result the DFM system must take each of the sensor’s results into a priority based
system where each sensor is capable of generating a positive result for life detection
independently of the others. This allows the DFM to correctly indicate the presence of life even
if some of the sensors are generating false results. In the same manner that shareholders have
control proportional of a company, each sensor will have a degree of influence over system,
which is determined by its accuracy. The software will take into account the different values of
influence and certainty generated by sensor data and make and educated decision whether to act.
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Major Components (Hardware/Software)
Figure 1. Major functional component diagram (Hernan Gonzales)
Figure 1 illustrates the major functional components of the DFM safety system. Any
element of hardware indicated in the diagram can be replaced, upgraded, or removed depending
of the manufactures desired implementation. It can be split up into three discrete units; the
sensor array, the logic controller, and the human interface devices.
The sensor array is the most notable portion of the DFM safety system. Each sensor gives
the logic controller independent data. If one sensor is determined to be obsolete, unnecessary, or
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too cost prohibitive to the customer they can make necessary adjustments without severely
impacting the DFM’s effectiveness. The sensors attempt to assess the environment in the car to
determine if a person is present and if the vehicle is approaching a dangerous state.
The logic controller is the element of the DFM that puts all of the sensor’s data to work.
Through the logic controller data is received from the sensors and the remote detector device to
determine the location of the driver and the state of the vehicle. The logic controller implements
all the software and consists primarily of the microcontroller.
Lastly, the interface devices are simply the remote detector, the transmitter device, and
the reset switch. Theses devices allow for the driver to have minimal interaction with the DFM
system. Since the DFM system is supposed to run autonomously it would only hurt the integrity
of the system to allow the end user too much interaction. Therefore, interaction with the DFM is
limited to the driver carrying the transmitter device, and using the reset switch in case of false
alarm.
2.2
Target Market/Customer Base
The DFM system will be marketed as a license to manufacture vehicles with the patented
technology, as well as software to run on a suggested set of hardware. Also validation
documentation and software will be provided to the customer to ensure the system can guarantee
the highest degree of safety. Automobile manufacturers will be the primary customer of the
DFM system, car buyers will be the secondary customers because they will be using the product.
In order to ensure that the product will be affordable to the average car owner the car
manufacturers will install, and purchase/manufacture the hardware. The manufacturer will be
able to keep production costs low by installing and manufacturing the hardware in house, rather
than buying a preassembled system. Likewise, they will not have to be a different version of the
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DFM for each model of car it is to be installed in. Rather, the manufacturer can take the core
software and microcontroller and incorporate it into their designs. Lastly, if the customer decides
that they do not want to implement the DFM system will all of the recommended sensors they
can decide to leave one or two out and set the configurations in the software provided to them
accordingly. This method puts most of the design control in the manufacturer’s hands and allows
the developers to focus of successful validation and enhancements, rather than manufacturing
processes.
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PRODUCT PROTOTYPE DESCRIPTION
This section addresses a minimalist implementation of the DFM system by reducing the
scope of the hardware used. The prototype will be demonstrated in from of a review panel in
order to evaluate its effectiveness. Due to time and budgetary constraints many aspects of the
systems were reduced to ensure that a working prototype will be completed.
3.1
Prototype Functional Objectives
The objectives of the prototype are to show that the DFM can in fact determine if a
human is present, it the environment will become hazardous, and if the driver is close enough to
provide assistance. The sensors can test if a human is present by providing data to the LabVIEW
(Laboratory Virtual Instrumentation Engineering Workbench) software where each sensor can
independently evaluate the vehicle. If the certainty is high over the majority of the sensors then a
person will be assumed present. This can be test buy setting off each sensor alone or in different
combinations to determine if the algorithm is affective.
Next, the environment is deemed hazardous if the temperature is rising or falling at a rate
that would become harmful. Not only is the current temperature taken into account, but also the
past temperatures. This way the DFM can set off the alarm even if danger is still minutes away.
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The system would be very ineffective if it sounds an alarm only when the environment is deadly,
or even if the driver is too far gone to ameliorate the situation.
Lastly, the prototype will show that a driver’s distance from the car is being monitored by
the DFM system. If the driver goes further than 10ft from the car to alarm will sound regardless
of the temperature in the car. Likewise, despite the driver’s distance from the car, the alarm will
sound if the temperature reached a fatal level. What is most important is any person or child left
in the car when the alarm sounds is removed before the system is reset, which is why the reset is
positioned in the rear center of the vehicle.
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3.2
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Prototype Architecture
Figure 2. Phase 1 prototype major functional component diagram. (Hernan Gonzales)
Figure 2 illustrates the major functional components of the DFM system prototype and
the interaction of its components. The primary difference from Figure 1 is the removal of the
CO2. Table 1 further elaborates on the reductions that will take place in order to complete the
prototype. Unlike the real-world implementation of the DFM there will be no microcontroller for
the system to be installed on, rather all of the software will be run through LabVIEW. While the
microcontroller would allow the DFM system run without a dedicated computer, it would not be
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flexible enough to create a very low scale prototype. Likewise, using a microcontroller rather
than simulation software would have it more difficult to test each component in the DFM at this
stage in development.
Features
Real World Project
Prototype
Heartbeat Sensing
An accelerometer will be installed that is
capable of sensing a heartbeat through the
vehicles back seat. The accelerometer can
detect small fluctuations in movement,
thereby indicating a heart rhythm.
A pulse oximeter will be attached to
a volunteer’s finger. This device will
give the same input values of the
accelerometer, but will require the
volunteer to attach the device.
Likewise, the presence of a pulse
will be the only criteria, not rhythm.
CO2 Sensor
The sensor will measure the level of CO2 in No CO2 sensor will be used for the
the vehicle. A steady increase will indicate prototype.
there is no ventilation and human or animal
is present.
Temperature Sensor
The temperature sensor will read in very
precise values to determine that rate of
temperature change to determine when a
threat may become imminent.
A temperature sensor will read the
current temperature of the room and
indicate when the level becomes too
dangerous for a human.
Motion Sensor
The software will analyze the values read
from the motion sensor over time to
determine if the readings may be influenced
by a person. An instance of motion without
life would be the movement of the vehicle’s
air conditioning vents.
The motion sensor will read in
several values over a short time
period. If motion is detected over
that time period then the software
will assert that a person is present.
Pressure Sensor
Like the motion sensor the values given to
the software will be used to determine if
there is not a pattern that could indicate life.
This would mitigate false alarms due to
devices that could trigger the sensor, such
as a child’s mechanical toy.
The sensor will be placed under a
cushion for the volunteer to sit on.
By sitting he or she will activate the
pressure sensor. This would
simulate a child sitting in a rear or
safety seat.
Microcontroller/CPU
A microcontroller will be used to implement
the software created by the DFM
development team. The controller will
interface with all the hardware and run the
analysis algorithms to evaluate the state of
possible passengers.
Labview simulation software will be
run in order to implement all the
logic necessary to run the DFM
system. Rather than have the
sensors wired into a microcontroller,
they will interface with the underlying
software using input/output device
known as a DAQ.
Reset Switch
A switch will be placed in rear of the vehicle
so that the driver can manually shut off the
device in case of a false alarm. The switch
will time out if the system still indicates
danger, and when the car is restarted.
A switch will be added to the set of
hardware, but the logical
implementation will not be as
elaborate.
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Radio Frequency
Reciever/Generator
A receiver will be placed in the car with the The same implementation will take
generator as a key fob. When the
place, but the generator will not be
generator goes out of range (10ft.) the car’s in the form of a key fob.
alarm will sound.
Alarm
The alarm will be implemented by whatever A small speaker will be used to
means the car manufacturer would like. It is generate noise and indicate the
strongly suggested that the car’s built in
alarm. A car alarm will not be
horn or alarm system be used given the
necessary to demonstrate.
public’s familiarity to car alarms and what
they entail.
Table 1. Feature comparison between full product and prototype
3.3
Innovative Features
The DFM is innovative in that is the first device to incorporate a series of environmental
sensors in order to determine the presence of life. By giving each of the sensors a different level
of importance the software will be able rate the severity of the situation as well as calculate a
level of certainty that a person is in danger. While safety features are added to cars each year,
few actually attempt to mitigate to vehicular hyperthermia. The DFM system will take into
account the temperature, both highs and lows, as well as the location of the driver to determine if
there is a passenger and whether he or she is in danger. By using extensively tested algorithms,
the DFM will be able to sound an alarm with a high degree of certainty of imminent danger.
3.4
Challenges and Risks
Currently the greatest risks for the project are lack of customer buy in, product
malfunctions, and caregivers become complacent. In the DFM system’s current state a prototype
is being developed to encourage customers to buy licenses. The current cost for one license of
the DFM system is $100. The license allows the manufacturer to use to patent and gives them the
right to use the developed software. If the customer is uninterested in the product, has found a
company that can do a better job under a different patent, or is unable to afford the licensing fee
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there is very little that can be done to save the DFM system. This is the greatest risk, and can
only be mitigated by keeping the price competitive and creating a product that top of the line.
Secondly, more serious concern is the malfunction of the hardware resulting in death.
This is always going to be an issue, but it is being mitigated by creating an assembly of sensors
that can be used to check for errors in the other’s readings. Likewise, extensive testing will go on
to ensure that the DFM has a high success rate. Through testing error can be found and mitigated
until the product has been significantly improved.
Lastly, complacency is one of the hardest risks to reduce because if comes from too much
faith in the product. The best way to reduce complacency is to require some interaction with the
caregiver over designated intervals of time. This way the caregiver is reminded of the device’s
need for human involvement and they will be less likely to take for granted the automated nature
of the system.
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PROTOTYPE DEMONSTRATION DESCRIPTION
The DFM system prototype demonstration will require a laptop computer, a copy of
Labview simulation software, a DAQ, a small speaker, a radio frequency generator, a radio
frequency receiver, a spring-loaded switch, a pulse oximeter, a temperature sensor, a pressure
sensor, and a motion sensor. A chair made to resemble the seat of a car will be placed in front of
the review panel. A pulse oximeter will also be placed in the chair, while the pressure sensor is
placed beneath the chair. The motion sensor will be directed toward the chair, no more than
three feet away. Lastly, a temperature sensor will be placed on the table next to a heating
element and a bucket of ice. Each of the sensors already connected to the DAQ will then output
their readings into LabVIEW.
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First the LabVIEW software will run through the simulation without anyone to influence
the sensors. This will indicate a run where no passenger is present in the car. The temperature
sensor will be placed in the bucket of ice to display temperature warning on the screen followed
by exposure to the heating element which should yield another warning. Despite the extreme
environments the DFM system will register no passengers and not set off the alarm.
In order to demonstrate a child left inside of a vehicle a volunteer from the development
team will sit in the demonstration seat. The sensor readings should be visible to the panel at all
times. The pressure sensor should indicate life, as well as the motion sensor. The volunteer will
then place the pulse oximeter around their finger so that the software will be able to register a
human pulse. Lastly, the temperature sensor will be exposed to the hot and cold environments
separately, each time setting off the alarm as the temperature values exceed predefined
thresholds.
As for the radio frequency generator and the radio frequency receiver, another volunteer
will take the generator away from the receiver, which will result in a decrease in measures signal
intensity. The alarm will go off when the intensity decreases to a predefined value which is
measured experimentally to be ten feet. When the second volunteer returns they must reset the
device by hand by using the reset switch. After which the temperature sensor will once again be
exposed to extreme temperature, which will again set of the alarm despite the location of the
second volunteer.
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GLOSSARY
Accelerometer – A device that measures the force on a sensor. Variations in the accelerometers
readings could be analyzed and to find a specific pattern such as a heart beat or motion
along a spatial axis.
Accuracy – The sensors ability to determine a correct result.
Not to be confused with precision, the exactness of the sensor’s result. Such as the
thermometer reads 75.001 degrees. Which is a precise value with +/- .001, but inaccurate
given that the temperature is actually 90 degrees.
Algorithm – A series of finite instructions that are given a particular order.
CO2 – Carbon Dioxide, chemical combination for air that is exhaled. The change in the air
composition from low to high levels of carbon dioxide may indicate human respiration.
CPU – Central Processing Unit, the device inside of a computer that executes machine code
(runs programs).
DAQ – Data acquisition, device that is used to send data to a computer using an external
interface, usually connected to proprietary hardware.
DFM – Don’t Forget Me, a system designed to prevent harm to humans and animals by detecting
life and high temperatures in a vehicle.
Hyperthermia – The state at which the human body is no longer able to cool down through
natural processes. The effort the body takes to reduce heat only causes one’s temperature
to rise due to the advanced state heat exposure.
Key fob: An item attached to a key ring or key chain, used either for decoration or to assist the
owner in the act of authentication.
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Microcontroller – A microprocessor that is optimized for self-sufficient systems, usually runs
on low power, and does not require a complex set of hardware.
LabVIEW – Laboratory Virtual Instrumentation Engineering Workbench, platform and
development environment for a visual programming language created by National
Instruments.
ODU: Old Dominion University
Proprietary Hardware: A device that is designed for specific purpose and lacks generic
qualities that would allow it to be used outside of its original implementation.
Pulse Oximeter – A medical device that is used to measure oxygen saturation in one’s
bloodstream. The arterial blood vessels expand and contract with each heart beat
changing the oxygen concentration which allows the device to measure pulse rate.
Respiration – Breathing in order to bring oxygen to the bloodstream and remove carbon dioxide.
The act of respiration reduces the amount of oxygen and increases the amount of carbon
dioxide enriched.
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REFERENCES
Kids and Cars. (n.d.). Kids and Cars. Retrieved January 28, 2007, from Kids and Cars Web site:
http://www.kidsandcars.org/
Oximity. (2002). Principles of Pulse Oximetry Technology. Retrieved January 21, 2007, from
Internet World Stats Web site: http://www.oximetry.org/pulseox/principles.htm