Smart Car Seat
Senior Design Project
Team BEAMAN
Alayna Boland, Michelle Goodman, Jessica Kim, Monica Kruse, Haley Nesmith, Chelsea Stowell
12/6/2012
ABSTRACT
Death of infants and small children from hyperthermia as a result of being left or trapped in a
vehicle for an extended period of time is a real concern for many parents. According the National
Highway Traffic Safety Administration, 527 children have died since 1998 from heatstroke
related causes in a parked car. There are several products on the market now or which are
proposed for production to solve this problem; however, none of these have managed to become
widespread due to malfunctioning devices and inconvenience to the caregiver. Our main
objectives for this program are to:



Develop a model that addresses concerns and problems of other current products with
similar functions
Create a working prototype of an infant car seat that alerts parents when they have
inadvertently left their child in the car, employing a reed switch mechanism and radio
frequency one-way transmitter
Ensure that our product is cost-effective and marketable to our target consumers
Our design team consists of six students with biomedical, mechanical, and electrical engineering
backgrounds and experience in testing products for companies. We hope to integrate our
technology with an existing car seat to provide an easier method of reaching customers, and we
want to potentially partner with an emergency alert system such as OnStar. Our project will be
considered a success if we complete all of our objectives in the time allotted to us.
PROBLEM INTRODUCTION
Since 1998, heatstroke resulting from being left alone in a hot vehicle has killed an average of 38
children annually, a total of 527 deaths.1 A nonscientific media survey done by Jan Null of San
Francisco State University found that between 1998 and 2009, over 50% of all vehicle-related
heatstroke fatalities occurred in children aged two years or younger.1
Warm days and enclosed vehicles together create a situation especially dangerous for infants and
young children for two main reasons. Firstly, children are more vulnerable to heatstroke than
adults. They cannot escape a hot vehicle. Their bodies have less surface area relative to their
volume, which means they have less skin available to dissipate heat.2 They also are not yet able
to sweat efficiently.2 As a result, an environment that seems to an adult caretaker to be cool
enough to be safe could be perilous for a toddler. Secondly, vehicle cabins can heat quicker than
the outside air on a warm or sunny day. The interior of a car parked facing the sun on a day in
the low 80s can reach 110°F within 45 min.3 Objects within the car, like seat belts, can easily
become hot enough to cause second-degree burns.4 If the weather is hot or humid enough, a child
can suffer fatal heatstroke in a vehicle even if multiple windows have been left open.3 In
Tennessee, hyperthermia severe enough to send the child into coma has occurred after spending
as little as 30 min in a hot vehicle.5
These deaths are almost always accidents. Null also analyzed the media accounts of why the
children in his data sample had been in the car. In 51% of incidents, the child’s caretaker forgot
the child was in the back seat and left the car. In 30%, the child was playing unobserved in a
parked car and became trapped. In 17%, the caretaker intentionally left the child in the car, not
realizing the danger.1 Therefore, several manufacturers have introduced products to remind or
alert caretakers that their child is in the car. However, a 2012 U.S. DOT-commissioned survey of
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the market found no available product to be both reliable and convenient, and none distinguished
between a temperate and a warm vehicle.1 This Senior Design Project will design a product to
remind a caregiver who has forgotten or intentionally left a child aged two years or younger in
the car of the presence of their child and to alert passersby if the car environment becomes
dangerously warm.
DESIGNS IN THE MARKET
As of July 2012, 18 devices designed to prevent infant heat stroke in unattended cars have been
developed.1 Each technology approaches the problem from a different way. Some devices
require a reminder key fob or bracelet, while another disarms the car to lower its windows.
Despite these differences in implementation, all devices perform the same main function:
sensing the presence of a child in an unattended car. A 2012 DOT- Commissioned Report put
three of these devices to the test in both standard and misuse scenarios. Two of them were
pressure pad based systems, and the other detected the presence of a child with a safety clip. All
of the devices were deemed inconsistent and unreliable.1
The devices require considerable effort from the caregiver to ensure successful operation and,
even then, the devices are inconsistent. The pressure pad systems worked only when the child
was in certain positions and of a particular weight; the safety clip failed if not correctly
positioned; and the devices experienced continual synching/un-synching while in use. Seven
devices are explained in further detail in the Appendix section; these mechanisms were used as a
starting point for our design concept, specifically the ChildMinder Smart Clip System (a childrestraint warning system) and the Backseat Minder (a vehicle-based warning system).
Our product will seek to improve reliability, consistency, and the ease of use for user by
including multiple sensing mechanisms and a layered sequence of alarms. We propose the use of
both a safety clip sensing mechanism and a pressure pad to detect the presence of the child.
DESIGN CONCEPT
Our product will be differentiated from those currently available by three attributes: improved
reliability, hot environment detection, and a graduated alarm system. Improved reliability will
please customers frustrated by constantly resetting other devices and will better protect children.
Hot environment detection will allow the device to distinguish between a child left in a car, who
is in an unsafe situation but whose life is not known to be at risk, and a child left in a hot car,
who should be rescued immediately by bystanders if necessary. The graduated alarm system will
reduce the likelihood that a caregiver would become frustrated by constant false or exaggerated
alarms and choose to ignore them all or discontinue product use.
The product will be built into a car seat and will plug into the 12 V “cigarette” outlet on the car.
Three sensors will input signals into an Arduino platform. A short circuit to the cigarette outlet
will detect whether the car is running by monitoring the outlet voltage. Initially, the Arduino will
continually check the input from the cigarette outlet. If the voltage level indicates the car is on, it
will continue to loop without executing any other task. Once the car turns off, the Arduino will
examine the input from a magnetic Reed switch attached to the child’s chest buckle, which will
indicate if a child is buckled in. If a child is still present, the Arduino will direct a small speaker
in the car seat to chime softly for 30 s. This will remind the caregiver that the child is in the car,
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addressing the root cause of 51% of fatalities. The caretaker can deactivate the chime by
unbuckling the child or restarting the car.
If the caretaker does not deactivate the chime before it shuts off, the Arduino will begin to
continually do two things. First, it will direct walkie-talkie-like system to send out RF pulses to a
receiving battery-powered key fob carried by the caretaker. Every 5 min, the car seat will
broadcast a signal that directs the key fob to vibrate in pulses for 5 s and to flash an LED labeled
“Remember Me!”. Additionally, a different pulse will be sent every second to confirm that the
key fob is within range of the car seat. If the caretaker walks out of range, and the key fob no
longer receives pulses, it will vibrate in pulses continuously and flash an LED labeled “Out of
Range” to alert the caretaker that contact with the car seat has been lost until the caretaker walks
back into range. Secondly, the Arduino will check the input from a thermistor positioned at the
top of the car seat as well as from the other two sensors. Every 2 min, it will record the
temperature in the cabin and calculate the difference between consecutive measurements. Some
rate of temperature increase or some absolute temperature (both values to be determined after
review of the medical literature) will indicate the child is in danger of hyperthermia. The
Arduino will direct the speaker within the car seat to sound a loud alarm and flash bright LEDs
on the car seat, alerting passersby that a child is in need of rescue. Prominent labeling on the car
seat itself by the LEDs will explain the cause of the alarm. The Arduino will also send a third
signal to the key fob, which will flash a “Baby in Danger” LED, vibrate continuously, and beep
through a small internal speaker. The only way to deactivate either the key fob or the car seat
alarms is to unbuckle the child.
WORK PLAN AND DESIRED OUTCOMES
We hope to educate parents about the risks of leaving children unattended in a car for extended
periods of time. We hope to partner with a car seat company such as Graco to make the car seat
monitor an included feature in the car seats. If the car seat monitor integrated into the car seat is
successful, we will look into partnering with General Motors to connect the Smart Car Seat with
OnStar for a more technologically advanced alert system.
To create the car seat monitor technology, we will research similar products and different types
of sensors as well as car seat models. A magnetic reed switch to detect if the child’s chest strap is
buckled will be the primary sensor for determining the presence of an unattended child. Coupled
with the on/off condition of the car ignition, the alerts will begin only if two conditions are met:
a child is in the car seat (buckle closed) and the car is off. The car seat monitor will be integrated
into the car seat and be tested. The car seat monitor will then be evaluated and modified until
shown to be reliable and durable. If the stand-alone car seat monitor system is successful, the
OnStar system will be researched for the potential to use alerts such as calling the driver’s cell
phone number or emergency personnel if necessary. A similar Smart Car Seat system may be
developed to integrate with the OnStar system. Similar testing will be performed to ensure that
the technology works properly.
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Figure 1. Gantt Chart
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We hope to have a finished product by the end of the grant period. If the product is not
completed, we hope that another group will continue it next year. We believe the product will
succeed because we have proficient group members with readily available knowledge and
resources. We are dedicated to finding a solution to the growing number of deaths associated
with infants left in cars.
MEASURES OF SUCCESS
This design project will be considered a success if the final product can reliably sense the
presence of an infant in a car seat and warn the driver or authorities after a period of being left in
a parked car rising to extreme temperature. Distinct measures of success in the engineering
design arise from improvements made on existing designs that have not been widely accepted
due to certain problem areas including: damage caused by spills on technology that is not water
resistant, poor accuracy in sensing the presence of an infant and failure to employ a sufficient
range to contact the driver. These issues of concern contribute to the lack of a satisfactory
product currently available on the market, despite the rising incidence of child mortality in hot
cars.
To achieve success in the Smart Car Seat, a working solution that addresses at least these three
shortcomings will be developed. In addition to meeting technical criteria, the car seat will also be
evaluated according to market standards. Cost-effectiveness is a parameter of success, indicating
that the product is both reliable and a viable option for business. Further, consideration of
customer desires, such as convenience, ease of use and peace of mind, is a pivotal factor of
success. Collaboration with and critiques from advisors in the fields of sensor design technology,
pediatrics, consulting, engineering business, and parents who compose the target customer base
will serve as internal measures of success throughout the process. This network will be
established via-email as well as major milestone meetings after an initial design is complete,
enabling significant progress by the end of the year.
TEAM MEMBERSHIP
Our design team is made up of Alayna Boland, Michelle Goodman, Jessica Kim, Monica Kruse,
Haley Nesmith, and Chelsea Stowell. We are advised by Dr. Kevin Seale.
Alayna Boland is a biomedical engineering major with extensive experience leading teams. Her
training includes medical imaging, organic chemistry, and Spanish medical terminology. She has
implemented class-wide social events with the Student Alumni Board and the Vanderbilt Interest
Project and was a founding member of the Vanderbilt After School Program, which tutors
Nashville schoolchildren. Alayna’s solid academic background, proactive mindset, and skill for
marshaling diverse personalities into a functioning team will provide both technical depth and
cohesion to our group.
Michelle Goodman is a mechanical engineering major with experience and skills derived from
the automobile industry. She can machine and weld, and she can work in CAD, ProE, Arduino,
and LMS Noise and Vibrations software. She has interned at General Motors in a mechanical
engineering role for the past two summers and worked with ISIS designing a remote-controlled
vehicle last spring. She has been designing racecars with Vanderbilt FSAE since her sophomore
year. She, too, is a practiced leader, having worked as a student manager at Vanderbilt Dining.
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Michelle’s familiarity with the automotive industry and practical skills will help us tailor our
design to the needs of the automakers and prototype a working system.
Jessica Kim is a biomedical engineering major with a minor in engineering management and
research experience in biomaterials, biochemistry, and microfluidics. She is trained in ImageJ,
Microsoft Visio, and Microsoft Project. She is a group leader for the schoolchild tutoring group
Vanderbilt Student Volunteers for Science and the current corresponding secretary for the Tau
Beta Pi engineering honor fraternity. Her project management training should help us meet our
milestones, and should any sort of image analysis or chemical sensor be required in the system,
Jessica is well qualified to choose the code or device needed.
Monica Kruse is a biomedical engineering/electrical engineering double major who works
summers at the U.S. Army Aviation and Missile Research, Development and Engineering Center
in Huntsville, AL. There, she has edited a standard operating procedure, designed a test for a
portable power supply, and presented design reviews. She is familiar with Solidworks. She has
worked in teams frequently through her Wilderness Skills club trips, her time with the VU Color
Guard, and her volunteer work in Zanzibar and on Alternative Spring Break. Monica’s electrical
engineering degree will be invaluable when we design or adapt circuitry.
Haley Nesmith is a mechanical engineering major with a minor in engineering management and
a customer’s perspective on design. She is a co-founder of Design for America at Vanderbilt.
Last spring, she initiated streamlining the Office of the Chancellor’s three databases into one and
successfully translated user observations into winning concept ideas for Oreck in class-client
presentations. She also has research experience in biophysics and molecular self-assembly
modeling. She has experience with LabVIEW, Java, Matlab, and Pro-Engineer. Haley’s
computational and coding experience will help us prototype a system, and her focus on the end
user and management training will guide our design towards a marketable product.
Chelsea Stowell is a biomedical engineering major with a varied background in both research
and industry. She has research experience in drug delivery, tissue engineering, and
mechanobiology; yet, this last summer, she interned at GE Healthcare, where she conducted
electromagnetic noise immunity testing. She has served in the Engineering Council and
Vanderbilt Student Government. She has a strong interest in communications and won “Best
Presenter” of about 15 undergraduates at her 2011 REU. Chelsea’s ability to organize and
integrate information will help keep the group centered in the big picture, even as she applies her
technical focus to help us specify the details of the project.
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REFERENCES
1. Arbogast, K. B., Belwadi, A., Allison, M. U.S. Department of Transportation, National
Highway Traffic Safety Administration. Report No. DOT HS 811 632. July 2012.
Reducing the Potential for Heat Stroke to Children in Parked Motor Vehicles: Evaluation
of Reminder Technology. www.nhtsa.gov.
2. Krous, H. F., Nadeau, J. M., Fukumoto, R. I., Blackbourne, B. D., Byard, R. W. (2001).
Environmental hyperthermic infant and early childhood death: Circumstances, pathologic
changes, and manner of death. The American Journal of Forensic Medicine and
Pathology 22(4):374-382.
3. Roberts, K. B., Roberts, E. C. (1976). The automobile and heat stress. Pediatrics
58(1):101-104.
4. Saitz, E. W. (1975). Seat belt buckle burn. Pediatrics & Adolescent Medicine
129(12):1456-1457.
5. Wadlington, W. B., Tucker, A. L., Fly, F., Greene, H. L. (1976). Heat stroke in infancy.
American Journal of Diseases of Children 130:1250-1251.
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APPENDIX
Market Survey
*Table and product descriptions reprinted from Arbogast, 2012.
Table 1: List of heat stroke prevention technologies.
#
Product Name
Sensing Parameter
1
ChildMinder Smart Pad System
Pressure/force in child restraint
2
Deluxe Padded Safety Seat Alarm System
Pressure/force in child restraint
3
SafeBABI
Pressure/force in child restraint
4
*Child Presence Senor
Pressure/force in child restraint
5
*Halo Baby Seat Safety System
Pressure/force in child restraint
6
*Car Seat Monitor
Pressure/force in child restraint
7
*Forget-Me-Not Car Seat System
Pressure/force in child restraint
8
*CAREseat Car Seat System Vehicle-based
Vehicle-based warning (Seat belt
warning
buckle)
BackSeat Minder
Time that the rear door was opened
9
(vehicle-based)
10
Child Minder Smart Clip System
Buckled chest clip on child restraint
12
Caregiver Reminder Bracelet
No sensing capability
13
Baby Bee Safe
No sensing capability
14
Toddler Wristband Safe "N" Secure Alarm System
No sensing capability
15
Toddler Wristband Safe "N" Secure Alarm System
No sensing capability
with parent alert button
16
Baby Talk GPS Child Tracker
No sensing capability
17
*The Life Warn System
Vehicle Integrated System
18
Kiddie Voice Child Reminder
Vehicle Integrated System
*Concepts not brought to market (at the time of this report) - July 2012
Eighteen products were identified with 11 of the 18 being commercially available. Those not
commercially available are marked with an asterisk.
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Below are brief descriptions of various devices that use different sensing parameters.
#1 ChildMinder Smart Pad System ($69.95) - Pressure/force-based system
The ChildMinder Smart Pad System (Baby Alert International, Dallas, TX) is a passive child
safety seat monitoring system comprised of the Smart Pad (sensing pad 152x101x4 mm; pad
cover 198x130x23 mm), system base unit and a Key Ring Alarm Unit (Figure 1).
Figure 1: ChildMinder Smart Pad System
(www.babyalert.info/index.php?main_page=product_info&cPath=1&products_id=2)
The pad is inserted into the child restraint and senses the presence of a child due to the pressure
applied to the sensor. There are five sensors distributed throughout the pad. The Smart Pad
should be placed under the cushion of the child restraint. Once the child is seated in the child
restraint, the Smart Pad System passively monitors the child in his/her child restraint. The Smart
Pad System is activated when a child is seated in the child restraint at which time the base unit
will begin to beep, indicating to the caregiver that he or she must synchronize the key ring alarm
unit to the base unit. Synchronizing involves pressing and briefly holding a button on the key
ring unit while in proximity of the base unit until the system quiets. An alarm sounds in the key
fob in six seconds after a parent or caregiver walks more than 15 feet from a vehicle while the
child remains seated in the child restraint.
#8 Backseat Minder ($139.99, $249.99 with prepaid installation) – Vehicle-based warning
system
The Backseat Minder (CSO RADIO, Lakewood, NJ) is based on the concept that placement of a
child in a child restraint in the rear rows of the vehicle takes more than 3 seconds. Any time a
child is placed in the rear rows of a vehicle, the driver will be forced to open the rear door. The
system senses that the door was open more than three seconds and if more than 3 seconds,
activates when the car is started. Then when the vehicle is turned off, a distinct chime will sound.
The chime can only be turned off by pressing a button located on the inside of the car’s rear
doors.
The manufacturer claims that it is not possible to seat a child in a car in less than three seconds
but one can put a coat or a bag in that time. Opening the door for less than three seconds will not
activate the system. The system also will not activate if the car is not started within several
minutes after the rear door is opened. This technology must be professionally installed.
(www.backseatminder.com)
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#10 ChildMinder Smart Clip System ($69.95) – Child restraint-based warning system
The ChildMinder Smart Clip System (Baby Alert International, Dallas, TX) is designed for a
child in a child restraint (Figure 6). The ChildMinder Smart Clip System replaces the child
restraint’s chest clip. The receiver/key ring alarm unit is placed on an automotive key ring. The
system reminds the parent/caregiver with an alarm six seconds after the parent/caregiver has
moved more than 15 feet from the child in the child restraint. The manufacturer claims that the
ChildMinder Smart Clip System does not compromise the crash protection provided by the child
restraint.
Figure 6: Smart Clip System
(www.babyalert.info/index.php?main_page=product_info&cPath=1&products_id=3)
#12 Caregiver Reminder Bracelet ($9.95) – Reminder only/no sensing system
The Caregiver Reminder Bracelet (manufacturer: John Grago) is a bracelet that can be attached
to the buckle of the child restraint when the child is not in the vehicle. Once you place the child
in the child restraint, the caregiver wears the bracelet. Once the caregiver reaches his or her
destination, the bracelet serves as both a tactile and visual reminder (Figure 8a and 8b). In
addition, the aluminum key attaches to the plastic photo holder on the key ring and provides an
auditory clue (when moved around). When the child is taken out of the child restraint, the
bracelet is placed back on the child restraint buckle.
Figure 8: (a) Caregiver Reminder Bracelet (b) Bracelet usage routine
(www.caregiverbracelet.com)
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#14 Toddler Wristband Safe “N” Secure Alarm System ($29.95) – Distance-based sensing
system
The Toddler Safe “N” Secure Alarm System (A-410) (Suddenly Safe “N” Secure Systems Inc.,
Bensalem, PA) is not specifically a heat stroke prevention technology but is designed to monitor
the location of your child relative to a receiver carried by the caregiver (Figure 10).
The transmitter is attached to the child’s wrist via the supplied keys so it is not easily removed. If
the caregiver goes beyond 6 to 50 feet (desired distance can be set) from the child, the receiver
will sound a loud alarm and vibrate. It also has a search mode that can be activated on the
receiver to help aid in finding the child if they are hiding or locked in a car.
Figure 10: Toddler Wristband Safe “N” Secure Alarm System
(www.shop.Suddenly Safensecuresystems.com/Toddler-Wristband-Safe-N-Secure-AlarmSystem-A-410.htm)
#16 Baby Talk GPS Child Tracker ($124.95) – GPS-based sensing system
Baby Talk GPS Child Tracker (Baby Alert International, Dallas, TX) is also not specifically
designed for heat stroke prevention but rather is used to determine if a child has arrived at a
predetermined destination such as daycare or preschool. (Figure 12) It is essentially a mobile
phone that requires the use of a SIM card. The device is programmed via computer and its
internal GPS notifies the caregiver’s phone when the child has arrived at the desired destination.
The caregiver can also monitor the child by remotely turning on the microphone. The system
requires that one phone stays with the child.
Figure 12: Baby Talk GPS Child Tracker
(www.babyalert.info/index.php?main_page=product_info&cPath=2&products_id=48)
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#17 Life Warn System (*not on market) – Vehicle-based technology
The Life Warn System is a vehicle-based solution. After the engine is turned off, the system
instantly and continuously scans the interior cabin/cargo and trunk space for exhaled carbon
dioxide (CO2). It uses multiple sensors located throughout the cabin space and can sense humans
or animals left behind. The system also has the ability to restart the engine, unlock doors, and
open the trunk for emergency responders.
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