Lab 1 – Don’t Forget Me ... Brandon Fields CS411
Lab 1 – Don’t Forget Me 1
Lab 1 – Don’t Forget Me: Product Description
Brandon Fields
CS411
Janet Brunelle
February 27, 2008
Lab 1 – Don’t Forget Me 2
Table of Contents
1 INTRODUCTION ..................................................................................................................3
2 PRODUCT DESCRIPTION .................................................................................................4
2.1
Key Product Features and Capabilities ...................................................................4
2.2
Major Components (Hardware/Software) ..............................................................6
2.3
Target Market/Customer Base .................................................................................8
3 PRODUCT PROTOTYPE DESCRIPTION .......................................................................9
3.1
Prototype Functional Objectives ..............................................................................9
3.2
Prototype Architecture ............................................................................................10
3.3
Innovative Features .................................................................................................14
3.4
Challenges and Risks ...............................................................................................14
4 PROTOTYPE DEMONSTRATION DESCRIPTION .....................................................15
GLOSSARY ..................................................................................................................................17
REFERENCES .............................................................................................................................19
List of Figures
List of Tables
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1 INTRODUCTION
Lab 1 – Don’t Forget Me: Product Description
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. As of now, modern cars do not 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 vehicle is occupied, the system can immediately 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 be checked by the accompanying software to ensure it is a person and not an obstruction that has been detected. A microphone will be implemented to monitor for loud noises which will help determine if the vehicle is occupied.
There will also be careful monitoring of the temperature, motion, and CO
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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.
When inputs from all the sensors collectively indicate that the vehicle is occupied, the vehicles alarm system will be initiated. Also, the driver’s key fob attachment will begin to vibrate to indicate that the alarm system has been activated. This device is autonomous and does
Lab 1 – Don’t Forget Me 4 not require the activation of the car's operator. It seeks to eliminate instances when one can let even important issues pass their attention.
2 PRODUCT DESCRIPTION
This section describes in detail the manner in which the fully implemented DFM safety system will run. Specifically, this section describes the sensors used in the system, and the key fob’s manner of interacting with the system. A breakdown of the product, the intended customer, and reliability are presented in this section.
2.1
Key Product Features and Capabilities
The DFM safety system is unique because it 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 false alarms or decisions made from insufficient data. Likewise, the system will not be rendered useless when one 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 system 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. A CO
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sensor 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
Lab 1 – Don’t Forget Me 5 based system where each sensor is capable of generating a positive result for life detection independently of the others.
Sensor Priority Value
Pulse Sensor
4
Motion Sensor
3
CO
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Sensor
Microphone
3
Pressure Sensor
2
1
Table 1. Sensor priorities
Table 1 indicates the specific priorities for the DFM system. In order for life to be detected with a high level of certainty the sum of the values must be greater than five. The specific values were designated based on the combination of sensor that would be needed to give a positive reading for the alarm to be initiated. For example, the pulse sensor and any of the three beneath it in the table will cause the alarm to go off. Likewise, the CO
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and the pressure sensor would not be high enough in priority to initiate the alarm, but if the microphone was also getting a positive reading the system acknowledge the presence of life.
The process of prioritizing the sensor’s results allows the DFM system to correctly indicate the presence of life even if some of the sensors are generating false results. In the same manner that shareholders have proportional control of a company, each sensor will have a degree of influence over the 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 an educated decision whether to act.
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2.2
Major Components (Hardware/Software)
Figure 1 illustrates the major functional components of the DFM system. It can be split up into three discrete units, the sensor array, the logic controller, and the human interface devices. In the diagram, the sensor array consists of all the devices depicted above the CPU, the logic controller is depicted in the box labeled as the CPU, and all of the human interface devices are depicted below the CPU.
Figure 1.
Major functional component diagram
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The sensor array is the most notable portion of the DFM system. Each sensor gives the logic controller independent data. 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. Individually each sensor is not a significant addition to a vehicle; however, nor is any individual sensor capable of making an accurate assessment of the vehicle’s occupancy. Together all the sensor are used to give the CPU a reliable representation of the environment inside the vehicle.
The logic controller is the element of the DFM system 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 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. Interaction with the DFM system is therefore limited to the driver carrying the transmitter device and using the reset switch in case of a false alarm.
The entire system will be installed as inconspicuously as possible. Few components should be visible to the passengers with the exception of the aforementioned reset switch, and they key fob device. While installations will vary based on the car manufacturer’s needs and design limitations there will be aspect of the installation that will remain constant. First of all, the reset switch will be in the back of the vehicle behind the middle seat (the typical location of a car safety seat). Likewise, the accelerometer sensor(s) will be installed inside the same seat as safety seat would be placed according to the law. Secondly, the temperature sensor, CO
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, and
Lab 1 – Don’t Forget Me 8 microphone can be placed anywhere on the interior of the vehicle as long as they would not come into casual contact with a passenger. Third, the pressure sensor, and the motion sensor will be placed so that they can most accurately assess the life of an infant in a car safety seat. Therefore, the motion sensor would be placed on the ceiling of the vehicle facing downward and directed toward the rear middle seat with the line of sight including the entire row of seats. Similarly, the pressure sensors will be installed beneath the rear row of seat cushions. Lastly, the CPU and the transmitter device will be installed anywhere in the vehicle’s interior the manufacturer desires.
Ideally, the two devices will be installed in a location that allows for easy maintenance and best signal interaction with the driver’s key fob. Overall, the system will not be readily apparent to passengers; however, the driver will be aware of the diagnostic light at the front of the vehicle and reset switch at the rear of the vehicle.
2.3
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 or 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 buy a different version of the
DFM for each model of car it is to be installed in. The manufacturer can take the core software and microcontroller and incorporate it into their designs. Lastly, if the customer decides that they
Lab 1 – Don’t Forget Me 9 do not want to implement the DFM system with 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 on successful validation and enhancements, rather than manufacturing processes.
3 PRODUCT PROTOTYPE DESCRIPTION
This section addresses a minimalist implementation of the DFM system by reducing the complexity of the software used. The prototype will be demonstrated in front 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 system can in fact determine if a human is present, if the environment will become hazardous, if the driver is close enough to provide assistance, and ensure that customer is satisfied with the product. The sensors can test if a human is present by providing data to the LabVIEW ( Lab oratory V irtual I nstrumentation
E ngineering W orkbench) software where each sensor can independently evaluate the vehicle. If the certainty is high over the majority of the sensors, a person will be assumed present. The sensor priority can be tested by setting off each sensor alone or in different combinations to determine if the algorithm is effective.
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 20ft from the car the 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. After demonstrating the full functionality of the
DFM system the customer will realize the potential of the system and attain a greater understanding of the power and functionality of the DFM system.
3.2
Prototype Architecture
The physical architecture of the prototype is focused around the LabVIEW simulation software. LabVIEW makes it possible to interact with an array of sensors by wiring them into the data acquisition device (DAQ). Once properly wired, the LabVIEW software can be used interact with the ports on the DAQ. Therefore, the LabVIEW software and the laptop take the place of the CPU. This removes the difficult task of creating the physical implementation of the
DFM system from their constituent components alone. Likewise, the algorithm can be programmed and tested without wasting time and money programming into a microcontroller.
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Figure 2.
Phase 1 prototype major functional component diagram
Figure 2 illustrates the major functional components of the DFM system prototype and the interaction of its components. Table 1 elaborates on the reductions that will take place in order to complete the prototype. Unlike the real-world implementation of the DFM system, 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 to run without a
Lab 1 – Don’t Forget Me 12 dedicated computer, it would not be flexible enough to create a very low scale prototype.
Likewise, using a microcontroller rather than simulation software would make it more difficult to test each component in the DFM system.
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
A pulse oximeter will be attached to a volunteer’s finger. This device will give the same input values of accelerometer can detect small fluctuations in movement, thereby indicating a heart rhythm. the accelerometer, but will require the volunteer to attach the device.
Likewise, the presence of a pulse will be the only criteria, not rhythm.
CO
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Sensor The sensor will measure the level of CO
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No CO
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sensor will be used for the in the vehicle. A steady increase will indicate there is no ventilation and prototype; rather, the sensor will be simulated in LabVIEW. human or animal is present.
Temperature Sensor The temperature sensor will read in very precise values to determine the 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
Pressure Sensor
The software will analyze the values read The motion sensor will read in 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. 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.
Like the motion sensor the values given to the software will be used to determine
The sensor will be placed under a cushion for the volunteer to sit on. if there is not a pattern that could indicate By sitting he or she will activate life. This would mitigate false alarms due to devices that could trigger the sensor, such as a child’s mechanical toy. the pressure sensor. This would simulate a child sitting in a rear or safety seat.
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Features Real World Project Prototype
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 an 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.
Radio Frequency
Reciever/Generator
A receiver will be placed in the car with the generator as a key fob. When the generator goes out of range (20ft.), the car’s alarm will sound.
The same implementation will take place, but the generator will not be in the form of a key fob.
Alarm The alarm will be implemented by whatever means the car manufacturer
A small speaker will be used to generate noise and indicate the would like. It is strongly suggested that the car’s built in horn or alarm system be used given the public’s familiarity to car alarms and what they entail. alarm. A car alarm will not be necessary to demonstrate.
Microphone A simple microphone will be integrated into the DFM system at the middle rear section of the vehicle behind the seat.
The microphone will merely check the intensity of noise in the vehicle. In the event that the noise is above a predefined decibel level the microphone will indicate life.
The computer's microphone will be used in LabVIEW to determine if the decibel level has reached a predefined level.
Table 2. Feature comparison between full product and prototype
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3.3
Innovative Features
The DFM system is innovative because it 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 determine the severity of the situation and 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 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 an occupant and whether he or she is in danger. By using extensively tested algorithms, the DFM system 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 becoming 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 the 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, there is very little that can be done to save the DFM system. These three factors are the greatest risk, and can only be mitigated by keeping the price competitive and creating a product that is top of the line.
Secondly, a more serious concern is the malfunction of the hardware resulting in death.
Death 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
Lab 1 – Don’t Forget Me 15 to ensure that the DFM system has a high success rate. Through testing, errors can be found and mitigated until the product has been significantly improved.
Lastly, complacency is one of the hardest risks to reduce because it 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.
4 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.
First the LabVIEW software will run through the simulation without anyone to influence the sensors, 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.
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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. Both the pressure sensor and the motion sensor should indicate life. The volunteer will 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 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 setting off 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.
CO
2
– 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 – Lab oratory V irtual I nstrumentation E ngineering W orkbench, platform and development environment for a visual programming language created by National
Instruments.
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.
