Alayna Boland, Michelle Goodman, Jessica Kim, Monica Kruse, Haley Nesmith, Chelsea Stowell
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.
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 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 child-restraint 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.
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, 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.
Figure 1. Gantt Chart
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.
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. 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.
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.
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.
Roberts, K. B., Roberts, E. C. (1976). The automobile and heat stress. Pediatrics58(1):101-104.
Saitz, E. W. (1975). Seat belt buckle burn. Pediatrics & Adolescent Medicine 129(12):1456-1457.
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.
*Table and product descriptions reprinted from Arbogast, 2012.
Table 1: List of heat stroke prevention technologies.
*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.
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).