EMERGENCY VEHICLE DETECTOR

Transcription

1 Proposal EMERGENCY VEHICLE DETECTOR ECE4007 Senior Design Project Section L03, EMV Detection Team Ehren Bendler Tyler Evans Jose Crespo Richard Yee Submitted September 15, 2008

2 TABLE OF CONTENTS EXECUTIVE SUMMARY...iii 1. INTRODUCTION Objective Motivation Background PROJECT DESCRIPTION AND GOALS TECHNICAL SPECIFICATIONS DESIGN APPROACH AND DETAILS Design Approach Codes and Standards Constraints, Alternatives, and Tradeoffs SCHEDULE, TASKS, AND MILESTONES PROJECT DEMONSTRATION MARKETING AND COST ANALYSIS Marketing Analysis Cost Analysis SUMMARY REFERENCES EMV Detection (ECE4007L03) ii

3 EXECUTIVE SUMMARY The Emergency Vehicle (EMV) Detector is an automated device that alerts car drivers when an emergency vehicle is approaching. The system consists of a microphone attached to the outside of a car, an A/D converter, different color LEDs, speakers, and a low-power computer. The detector receives audio input through the microphone, digitizes the signal using the A/D converter, and detects patterns that indicate an EMV siren using the computer s softwareimplemented filters and DSP algorithms. Upon detection, the device turns off the car s stereo, flashes an LED, and plays a message warning the driver that an EMV is approaching. A car s audio and sound isolation may prevent a driver from hearing an EMV siren and pulling over in time. By quickly notifying drivers of approaching EMVs, the EMV Detector will save lives and money by reducing EMV collisions and improving EMV response times. The device will be sold to car owners to install in current cars and car manufacturers to install in new cars. Unlike other designs, which require transmitters to be placed in EMVs, this design is a client-side product, which reduces cost and increases usability. The outcome of this project will be a prototype of the EMV Detector. It will be able to detect different types of EMV sirens under different environmental conditions, and it will do so fast enough to allow a potential driver to clear the road before an EMV arrives at his or her current location. The total estimated cost of the project, including labor and equipment, is $51, EMV Detection (ECE4007L03) iii

4 EMERGENCY VEHICLE DETECTOR 1. INTRODUCTION Emergency medical vehicle collisions are estimated to occur approximately 12,000 times and cost millions in liability claims in a given year [1]. The EMV Detector proposed will consist of a microphone attached to a car that will be monitoring sound at all times. Once the audio is received, the signal is converted into a digital signal using an analog-to-digital converter (ADC). The device then detects patterns that indicate that the audio signal contains an EMV siren using software-implemented filters and DSP algorithms. Upon detection, the device turns off the vehicle s radio, flashes an LED, and plays a message alerting the driver that an EMV is approaching. 1.1 Objective The EMV Detector is designed to be placed in any vehicle, alert the driver of an incoming EMV, and will work as a standalone product. A microphone will be placed outside of the car and will be connected to the system through a wire. The system will be placed on the dashboard and will be powered by the car in the final design. Once the microphone picks up audio of an EMV siren, a visual signal using LEDs will be displayed along with an audio message to warn the driver that an EMV is approaching. 1.2 Motivation The EMV detector will greatly reduce the chance of accidents caused by motorists who are unaware that an EMV is approaching. For auditory signals to be detected by the human ear, that sound must be 8-12dB above background noise. When traveling in a car with the radio EMV Detection (ECE4007L03) 1

5 turned off and the windows up, the noise inside the car is measured to be an average of 70dB. Sirens are regulated to be approximately 120dB at 10 meters to avoid permanent damage to the human ear. With the motorist at a speed of 56 mph and the EMV at 75 mph, the motorist needs 50 meters to have a 6 second response time. At these speeds the siren sound level is 74dB which is not loud enough to warn the driver when taking into account noise inside of a car [2]. The detector proposed will also be able to enhance the response time to EMVs, which can save lives. This product is designed to be placed in any motorist s vehicle without causing excessive clutter. Currently, there are patents such as 6,788,101 that propose a receiver-and-transmitter system in which the EMV will contain a transmitter that sends a signal to a receiver in the consumer s vehicle. The proposed EMV Detector will be a client-end product and will not require a transmitter for the EMV, which reduces cost and increases possibility of its use. 1.3 Background At the current time, there are no commercially available products that match the full description of the proposed design to detect EMVs. There is a patent that fits the description of the proposed design, but it is implemented in a different way. United States patent 6,778,101 proposes the use of a transmitter in an EMV and a receiver in the consumer s vehicle [3]. The design has not been released in the market, and the proposed design differs in the implementation of the detection of the EMV for the consumer. There are both audio detection and vehicle detection systems, but no comprehensive system is used to detect EMVs. Audio Detection Digital signal processing is one of the main commercially available applications in audio detection. A recent development in audio detection is the use of the audio identification system EMV Detection (ECE4007L03) 2

6 Waveprint [4]. Waveprint can detect an audio signal that has been degraded by using a temporal-ordering-based processing system, and is more accurate than the previous state-of-theart system while being more efficient and flexible in memory usage and computation. MATLAB is another program that is widely used in the field of audio processing. The design of FIR, IIR, and fast Fourier transform processes is possible with the use of MATLAB. These filters can be used to detect and manipulate the desired signal. Vehicle Detection Magnetic sensor technology is the most widely used technology for vehicle detection. By detecting a vehicle s disturbance of the earth s magnetic field, these sensors can detect vehicles and perform multiple functions such as traffic monitoring, gate opening, and vehicle location. Another method for vehicle detection is the use of laser detection systems. These systems use lasers to scan the roadway and create a 3D image of the vehicle [5]. This image is then analyzed to find which vehicle it is. Both magnetic sensor and laser detection systems for vehicle detection would require a transmitter to send confirmation of detection to a receiver in the consumer s vehicle for application in an EMV detection system. 2. PROJECT DESCRIPTION AND GOALS The main goal of the EMV Detector is to increase the amount of time that a driver has to react to a nearby EMV by warning the driver with audio and visual stimuli. When the system detects a siren, it cuts power to the radio, lights an appropriately colored LED (blue for police, red for fire, and yellow for ambulance), and plays an audio message warning the driver of the approaching EMV. After the EMV passes, power is restored to the radio and the LED is turned EMV Detection (ECE4007L03) 3

7 off. In order to increase the likelihood of the widespread adoption of the system, it will be small, require minimal user effort to install, and cost less than $200. Features of the EMV Detector: Increased response time for vehicle operator Small in size Easy to install Less than $200 Audible and visible warnings 3. TECHNICAL SPECIFICATIONS To achieve the goals of the project, the team has outlined a set of specifications, which are shown in Table 1. Table 1. Specifications for the EMV Detector Detection level Refresh time Size (L x W x H) 5dB over ambient noise 2 seconds 6 in x 6 in x 1 in Normal human hearing requires a sound to be 8dB above the ambient noise in order to be detected, and the sound insulation of a normal vehicle causes a 20dB insertion loss [2]. By mounting the microphone outside the vehicle and designing a sensitive detection algorithm, the EMV Detector can provide a significant improvement in safety. The refresh time needs to be low in order to make the device useful. Ideally, all processing would be done in real time, but it EMV Detection (ECE4007L03) 4

8 is extremely difficult to get that level of performance from a computer that can fit within the desired size. The size constraint was chosen so that the EMV Detector could be placed in the vehicle in such a way as to be easy to install and unobtrusive to the operator once it is in place. 4. DESIGN APPROACH AND DETAILS 4.1 Design Approach The chief problem in the project is distinguishing sirens from the background noise that is prevalent when a vehicle is in motion. At this point, the team is aware of two characteristics of typical sirens that may aid in detection. The first is that most sirens move between high and low frequencies at a steady pace (currently, the rate of change and precise frequencies are unknown). The second helpful aspect is that sirens exhibit a clear Doppler shift, which will aid the team in being able to distinguish between sirens that are approaching the vehicle and those that are moving away. In the early stages of the project, the team will be devoted to researching exactly how these aspects can be used to detect a siren. The EMV Detector will be a three-part system consisting of a microphone, a low-power computer, and warning indicators. The operational flow of the EMV Detector is shown in Figure 1. The computer will likely be based on a low-power x86 instruction set processor such as Intel s Atom, which will allow the team to run common software packages such as MATLAB while also having a realistic chance of fitting into the size specified for the final product. If the Atom cannot provide enough performance for the task, switching the computer to an Intel Celeron based system would be a practical alternative that would provide increased performance in exchange for higher power usage and a higher per-unit cost. Algorithms for detection will be developed and tested on a typical desktop computer until the team achieves nearly full EMV Detection (ECE4007L03) 5

9 functionality. After this baseline is reached, development will be moved to the low-power system in order to begin optimizing for performance. Figure 1. EMV Detector program flow. 4.2 Codes and Standards USB 2.0 specifications entail data rates between Mb/s through the use of a shielded, twisted wire pair through a serial connection. USB 2.0 uses Non-Return to Zero Inverted (NRZI) system to encode data. RS232 standard is an asynchronous serial communication method. The standard set for data rates was set as 20 Kbps, but current devices have maximum speeds as high as 1.5 Mbps with a maximum cable length of 50 feet or cable length equal to a capacitance of 2500 pf [6]. EMV Detection (ECE4007L03) 6

10 The TSR connector, also known as an audio jack, is used for audio applications. The TSR connector consists of two to five conductors depending on which application the connector is used. There are several standard sizes, but the most commonly used standard for microphones is the 3.5mm standard [7]. 4.3 Constraints, Alternatives, and Tradeoffs Microphone There are many different types of microphones that could be used for audio detection. Due to budgetary concerns, some of them cannot be used in this design. For example, microphones specifically designed for the outdoors were one of the options considered but not used due to economic restrictions. These outdoor microphones are designed for long periods of unattended use and come with protection against corrosion and wind. This shield against corrosion and wind would be practical for use outside of a car, where the microphone is subject to the open air at high speeds. The use of microphone arrays to capture EMV sirens is another possible alternative. The multiplexing of the inputs of multiple microphones placed strategically in an area can be used in audio detection and location. However, due to budgetary constraints and time constraints regarding the placement of these microphones to maximize efficiency, the use of microphone arrays is not likely. Audio Detection and Processing Active noise control is an alternative option in the detection of acoustic signals. Ambient noise data received by a microphone is converted into a digital signal through the use of an ADC. This signal is then input to a DSP processor and converted into an inverse signal that is outputted EMV Detection (ECE4007L03) 7

11 to a speaker to negate ambient noise. This technique is useful for operations where an audio signal must be obtained from a noisy environment [8]. An alternative in processing of the audio signal is the use of a dedicated digital signal processor which is specifically designed to handle DSP tasks. These processors are most frequently used in processes that are continuous such as input audio signals. These processors are expensive and also require the soldering of the processor to a printed circuit board which contains the other electronics that are necessary in the design of our project [9]. The addition of directional detection of the EMV siren is an alternative that can be implemented to add functionality and complexity to the project. Microphone arrays would be used to determine the approaching direction of the EMV in relation to the vehicle. Extra algorithms would be implemented to account for this addition. Budgetary and time concerns will be taken into account to decide if this is a viable option to be implemented in the design. 5. SCHEDULE, TASKS, AND MILESTONES As seen in Figure 2, the team s first major task will be to gather all of the materials needed to implement the design, including inputs, outputs, and parts. Then the team will divide into two groups: one group will handle the software component of the device, and the other will handle the hardware component. If one group falls significantly behind in the timeline, the other group will assist them to maximize time efficiency. After the hardware and software components have been integrated, the remaining time will be devoted to testing and debugging the device. The most difficult and most important task of this project will be the siren detection, which involves complex algorithms that must account for factors such as background noise and Doppler effect. All other tasks will be relatively straightforward. EMV Detection (ECE4007L03) 8

12 Figure 2. Project schedule. 6. PROJECT DEMONSTRATION The EMV Detector will be demonstrated in the laboratory in Van Leer. The device will be connected to a radio s power supply and to the LED output system. A siren recording will be played near the microphone of the EMV Detector. The device is functional if it cuts power to the radio, activates the LED output system, and plays a prerecorded message alerting the driver of an approaching emergency vehicle. The next feature to be tested will be the device s ability to filter out ambient driving noise while still detecting the siren noise. This will be done by playing a recording of ambient driving noise, and also playing a recording of ambient driving noise along with a siren. The ambient driving noise only should get no response from the device, while the ambient driving noise with the siren should turn off the radio and activate the output system. Another feature to be tested is the device s ability to correctly detect Doppler shifted siren signals. Repeated tests will be conducted by playing recordings of sirens with varying Doppler EMV Detection (ECE4007L03) 9

13 effects and a varying volume on inputs. The sensitivity requirement will be satisfied if the device correctly detects the siren at a received volume of 5dB above the ambient noise level. The refresh rate requirement will be satisfied if it can give an appropriate output within 2 seconds of detecting a siren after repeated tests. 7. MARKETING AND COST ANALYSIS 7.1 Marketing Analysis The EMV Detector is a major safety improvement for vehicles. Ambulances are 13 times more likely to have accidents than consumer vehicles and are five times more likely to cause an injury [10]. The device requires only installation in consumer vehicles and not the EMVs. The device is low-power and can easily be powered by the vehicle s battery. There are similar products on the market, but they require a radio transmitter to be installed in the EMVs and a receiver in consumer vehicles [11]. The EMV Detector will give drivers more time to recognize and respond to approaching EMVs, greatly reducing the chances of a collision. 7.2 Cost Analysis The EMV Detector can be developed and prototyped for a total cost of $51, Equipment costs are $159.37, and labor costs are $32,900. The project costs are located in Table 2. The labor costs were calculated using an average wage of $50/hour. The fringe benefits were calculated as 25% of the total labor cost, and the total overhead was calculated as 25% of the labor, equipment, and fringe benefits costs. The selling price of the EMV detector would be $175 per unit. Estimated sales totals over five years are 100,000 units for a profit of $1,563,000. After development costs, the profit is $1,511, EMV Detection (ECE4007L03) 10

14 Table 2. Project Costs PROJECT ELEMENT LABOR HOURS LABOR COST EQUIPMENT COST TOTAL ELEMENT COST Device Construction DSP processor 100 $5, $ Microphone connection 20 $1, $19.80 A/V output 50 $2, $35.45 DSP software development 300 $15, $0.00 $15, Class lecture and meetings 188 $9, $0.00 $9, TOTAL LABOR 658 $32, TOTAL EQUIPMENT $ FRINGE BENEFITS $8, TOTAL OVERHEAD $10, PROJECT TOTAL $51, SUMMARY At this point, the team has completed the following tasks: Research state-of-the-art technology related to the project. Decide on features and technical specifications of the device. Perform marketing and cost analyses. Devise a schedule, and divide the tasks. The team is now ready to gather materials and begin implementing the design. 9. REFERENCES [1] J. Clawson, R. Martin, G. Cady, R. Maio, The Wake Effect: Emergency Vehicle- Related Collisions, [Online],[cited 2008 Sep 9], Available: EMV Detection (ECE4007L03) 11

15 [2] M. Miller, R. Beaton, The Alarming Sounds of Science, [Online],[cited 2008 Sep 14], Available: [3] T. Turbeville, J. Majka, Emergency Vehicle Detection System, U.S. Patent 6,778,101, November 27, [4] M. Covell, S. Baluja, Known-audio detection using WAVEPRINT: Spectrogram fingerprinting by wavelet hashing, [Online],[cited 2008 Sep 9], Available: [5] OSI LaserScan, OSI LaserScan - Laser Detection Sensors and Vehicle Detection Systems for Toll and Traffic Management, [Online],[cited 2008 Sep 8], Available: [6] Lammert Bias, RS232 Specifications and standard, [Online],[cited 2008 Sep 9], Available: [7] International Textbook Company, International Library of Technology: A Series of Textbooks for Persons Engaged in the Engineering Professions and Trades, Or for Those who Desire Information Concerning Them, London, England: International Textbook Company, pp , [8] M. Onishi, Y. Nakamura, T. Inoue, and A. Takahashi, Active Noise Control System, U.S. Patent 7,340,064, 27 May, EMV Detection (ECE4007L03) 12

16 [9] S. Smith, The Digital Signal Processor Market, [Online],[cited 2008 Sep 9], Available: [10] D. Long, Facts on Emergency Vehicle Driving, para. 6, [Online]. Available: [Accessed Sept. 12, 2008]. [11] T. A. Turbeville and J. R. Majka, Emergency vehicle notification system, U. S. Patent 7,397,356, 8 July, EMV Detection (ECE4007L03) 13