Portable Electronic Device Detector

Transcription

1 Portable Electronic Device Detector By: Sarah A. Kelly ECE 410: Senior Project Final Paper March 27, 2012

2 Sarah Kelly 2 Abstract: Locating portable, electronic devices prior to critical flight periods is an issue with no calculable solution. Current restrictions deny use of most signal-transmitting electronics during critical flight periods, though many are inclined to disregard these restrictions. Passenger indifference poses a potential threat to plane communications systems. In this work, a simplified RF detector is used to alert flight attendants to activated portable electronics. The paper will describe the circuitry and theory involved in device development.

3 Sarah Kelly 3 Table of Contents Abstract 2 Table of Contents 3 A. Project Scope 4 B. Customer Needs 4 C. Product Design Specifications 6 D. Concept Generation 7 E. Detailed Design 8 F. List of Tests and Results Test Plan Test Results 12 G. Bill of Materials 13 H. Prototype Cost 14 I. Summary/Conclusion 15 Economic Analysis 15 Health and Safety 15 Social Analysis 15 Political Analysis 16 Environmental Analysis 16 Sustainability 16 J. Schedule 17 K. References 18

4 Sarah Kelly 4 A. Project Scope: Department: Project Name: Project Contact: Christian Brothers University School of Engineering Portable Electronic Device Detector Sarah Kelly Computer Engineering major Contact Phone: Contact skelly6@cbu.edu The scope of this project consists of the design and implementation of a Portable Electronic Device (PED) Detector. The unit consists of one LED output, and a piezo buzzer that should signify the relative safety level of a certain electronic device used by passengers during critical flight periods according to legislation and regulation set forth by various avionics commissions in the United States. B. Customer Needs: The final customers for this project will be the flight attendants and crew of multiple commercial airlines. Currently, there is no comparable device in use. At present the only way to determine whether passengers are using unsafe electronics is by visual inspection. Flight crew need a method by which to direct passengers in what electronic devices are suitable for use during critical flight periods. The project has the following specifications based on customer needs: Safe and Simple: Those who are untrained in the use of complicated Radio Frequency Detectors will be utilizing this device regularly. Therefore, one should be able to use the device without any knowledge of legislation, frequencies, or specific electronics outside the range of acceptability. The user should be able to

5 Sarah Kelly 5 determine based on a buzzer/led system whether or not the passenger s apparatus is safe for use. Sturdy: The unit must be capable of enduring attrition due to regular use by multiple customers. Design must include parts of the highest and most robust quality, and must feature a casing capable of withstanding drops from waist height. LED s: The LED indicator lights must be of the highest quality to ensure malfunction does not occur. The red LED must indicate an unacceptable frequency range for safe use of Portable Electronic Devices. Space Utilization: The device must be extremely compact as the inside of a plane in transit is often cramped, and a flight attendant may be required to stow the device quickly in the event of a passenger emergency. Wiring and Circuitry: It is imperative that wiring and circuit complexity be at a minimum to elongate lifespan. All wires and circuit components, save for the antenna, must be kept within the casing of the device in order to ensure that the product s longevity meets expectations. Certifications: Federal Aviation Administration certification and approval that device employment satisfactorily aids in prevention of passenger use of unauthorized Personal Electronic Devices (PEDs). The Needs-Metric matrix shown below in Table 1, illustrates the customer needs compared to the actual design specifications.

6 Sarah Kelly 6 NEEDS Research User friendly unit Non-disruptive alert Battery compatibility Sturdy casing Compliance with FAA METRIC Power supply Alert Led s Non-metallic Casing Charging Unit On/Off Switch Training video Table 1: Needs-Metric Matrix C. Product Design Specifications: The frequency detection system must be precise and user friendly to ensure public safety, and minimize the potential for conflicts regarding accuracy. Additionally the frequency detection device must: Quickly and easily alert the operator if an unauthorized Personal Electronic Device (PED) is in use. Utilize a simple, easy to interpret, method of indicating the frequency severity.

7 Sarah Kelly 7 D. Concept Generation: There are several concepts related to Radio Frequency detection. Radio Frequency detection simply consists of intercepting a sinusoidal signal passing through space. This signal is composed of electromagnetic radiation that will eventually be received by some form of base station. Different electronic devices all have some form of Radio Frequencies. Mobile phones represent one of the most significant issues plaguing acceptable Portable Electronic Device use in-flight. On average, mobile phone frequencies operate with a wavelength of 30cm between 872 and 2170 MHz. This means that when the device is activated the signal has high frequency and energy. Global System of Mobile Communication (GSM) digital phone transmissions are allocated two frequency bands: one at 900MHz and the second at 1800MHz. Within each band there are roughly 100 carrier frequencies on 200kHz spacing; effectively supporting 8 conversations within each time slot. Most passengers are unaware that mobile phones continuously transmit signals to register availability to the nearest base station, and while moving between cells will maintain the strongest connection for as long as possible. Considering that the strongest radiation from a mobile phone is about 2W, a connection can be made with a base station as far as 3km (9, ft) away. Therefore, during critical flight periods, take-off and landing with altitudes at or below 10,000 ft, it is feasible for a mobile phone to successfully maintain a connection with a base station, and interfere with the frequencies on which air-to-ground communication is being made from the cockpit. Although research has not yet been able to prove conclusively that these signals

8 Sarah Kelly 8 impact avionic communication equipment, suspicion is severe enough to result in legislation prohibiting the use of these devices to ensure passenger safety. Additionally, it would be expensive and nearly impossible to test interference caused by each individual electronic device as they evolve and hit the market. E. Detailed Design: Figure 1: Portable Electronic Device Detector Circuit Because the transmission frequency of some electronics range from 0.9GHz to 3GHz with a wavelength of 3.3cm to 10cm a circuit capable of detection in the gigahertz range is necessary for this circuit.

9 Sarah Kelly 9 Figure2: RF Capture This circuit utilizes a 0.22F disk capacitor (C3 above) and leads as a small gigahertz loop antenna to acquire radio frequency signals. The 0.22F capacitor is chosen because it has a large surface area to accept energy while maintaining a low value. In order to detect the signal the capacitor is arranged similarly to a mini loop aerial enabling it to oscillate and discharge current. As C3 intercepts signals from the electronic device it stores and transfers energy as current to the inputs of the integrated circuit, CA3130 (See Figure 3 below). Figure 3: CA3130 Pin-out

10 Sarah Kelly 10 The integrated chip CA3130 is a 15MHz, BiMOS, Operation Amplifier with MOSFET inputs and Bi-Polar output. Inputs contain MOSFET transistors that provide a low input current as well as high input impedance. The CA3130 is used as a current-tovoltage converter. Initially output should be 0, but when a small current is induced in its inputs, the CA3130 can give a high output. When an electronic device within the allotted frequency is activated and begins to pulse, the capacitor oscillates and releases the excess energy into the inputs of the integrated chip. The red LED flashes as an indication of the oscillation and ultimately a hazardous device is identified. (Figure 4 below) Figure 4: LED/Buzzer Configuration The buzzer is activated when capacitor C4 and large resistor R1 keep noninverting input stable for easy output swing to high. The feedback resistor, R3, makes the inverting input high when the output becomes high. Capacitor C5 connected across the

11 Sarah Kelly 11 strobe pin for phase compensation and gain control trigger the NE555 timer with its high/low alternation through capacitor C7. Ultimately, this disturbance is indicated by a series of high-pitched beeps from the buzzer. F. List of Tests and Results: 1. Test Plan: Figure 5: Circuit Diagram Flow Chart Test individual components on a digital multi-meter Ensure that the LED can be illuminated in current positions Observe sinusoidal reactions on digital oscilloscope while mobile phone is used within 1.5m of antenna

12 Sarah Kelly 12 Observe sinusoidal reactions on digital oscilloscope while Portable Electronic Devices are activated within 1.5m of antenna. Activate different Portable Electronic Devices within 1.5m of antenna-observe propriety of LED/Buzzer reactions Repeat experiments with commercial RF detector to check accuracy 2. Results: Test Cycle 1: Test 1 revealed that the N741 was not an appropriate substitute for the CA3130. The red LED was constantly illuminated, and some sinusoidal activity was noted on the digital oscilloscope when a mobile phone was activated, though it could not be replicated. A piezo buzzer was substituted for the green LED in the diagram, but would not work most likely due to the lack of pulse generation from the NE555 timer. A commercial RF detector was not yet on hand for this test. The diagram used can be viewed below. (The CA3130 was ordered after completion of Test Cycle 1) Test Cycle 2: Test Cycle 2 was extremely positive. Inclusion of the correct Operational Amplifier, the CA3130, seems to have been the only issue in the last testing cycle. It appears that when the circuit is activated with a power supply of 9V, and is allowed to warm up, or begin oscillating prior to engaging the mobile device, the detector s response time was consistently less than 3 seconds from cell phone activation. Additionally, the device consistently alerted users to video capturing device activation. The product works comparably to the commercial RF detector purchased for testing.

13 Sarah Kelly 13 G. Bill of Materials: 2.2M Resistor (2) 100K Resistor 1K Resistor 12K Resistor 15K Resistor 22pF Capacitor (2) 0.22F Capacitor 100F Capacitor 47pF Capacitor 0.1F Capacitor (2) 0.01F Capacitor 4.7pF Capacitor CA3130 Operational Amplifier NE555 Timer LED (2) Antenna ON/OFF Switch Power Supply

14 Sarah Kelly 14 H. Prototype Cost: Component Price 2.2M Resistor (2) 100K Resistor 1K Resistor 12K Resistor $ K Resistor 22pF Capacitor (2) 0.22F Capacitor 100F Capacitor 47pF Capacitor 0.1F Capacitor (2) $ F Capacitor $ pF Capacitor CA3130 OpAmp $1.52 NE555 Timer $1.99 LED (2) $1.69 Antenna $15.00 ON/OFF Switch Power Supply

15 Sarah Kelly 15 TOTAL COST $27.85 I. Summary/Conclusion: The design and implementation of a Portable Electronic Device Detector that meets all the design specifications and customer needs is complete. It is my belief, based on positive test results that it will operate with superior functionality. The device designed will be the most cost effective, simple, and efficient model for the purposes requested by the customer. It can be subject to the following analysis: Economic Analysis: Compared to extremely costly and intricate RF detectors, this design is relatively inexpensive. Part replacement for this unit will also be extremely simple, cheap, and fast while maintaining an extremely good quality. Health and Safety: This device has the potential to assist flight attendants in locating hazardous portable electronic devices. The use of LED s provides a noticeable indicator to the flight attendant. The piezo buzzer provides an additional level of protection by theoretically encouraging passengers to discontinue use of their devices out of annoyance or concern for being singled out as a violator. The project s concept is based on the idea of keeping airline passengers safe by preventing potential interference with avionic communications.

16 Sarah Kelly 16 Social Analysis: The addition of this Portable Electronic Device Detector ensures a safer and minimal anxiety environment for travelers and flight crew alike. It also has the potential to minimize conflict between flight attendants and difficult passengers by providing a quantitative means by which hazards can be located. The peace of mind associated with knowing the threat of communication jams during flight will be reduced should also serve as a comfort to everyone on the vessel. Political Analysis: Portable Electronic Device Detector implementation could reduce necessity for increasing and revisiting current and future legislation as presented by the F.A.A. and F.C.C. As RTCA testing continues, updates could simply be made to airline communications standards and Portable Electronic Device Detectors could easily be altered to meet the changing demands of the public. Environmental Analysis: Beyond minimizing air-to-ground communication issues with different cell networks, this product would have little more impact on the environment than a standard television remote control. Sustainability: Due to the simplicity of this design, changing allowable frequencies is as easy as increasing or decreasing lead lengths in the circuit. This project is extremely sustainable

17 Sarah Kelly 17 in the long term as well as having notable flexibility. It is inexpensive and necessary components such as 9V batteries are readily available and accessible. J. Schedule: Research Component Acquisition Circuit Assembly Circuit Testing Application Testing Report Composition Presentation Composition 2011 August September October November December

18 Sarah Kelly 18 K. References: Cell phone Detector AKA Mobile Bug Unknown, Electro-Schematics URL: GSM Phone Signal Analysis Steer W., Tech Mind URL: Fact Sheet: Cell phones, WiFi, and Portable Electronic Devices on Airplanes Duquette A., Federal Aviation Administration (FAA) URL: AC B Use of Portable Electronic Devices Aboard Aircraft AFS350, Federal Aviation Administration URL: /go/document.information/documentid/22448 Basic Engineering Circuit Analysis, Irwin J.D., 8 th Edition