Group D, Fall 2010 Stephen Watson, Charles Logan, Joshua Guinn, Derrick Nelson EVADE: Emergency Vehicle Alert DEvice EVADE: Emergency Vehicle Alert Device Project Origination: Have you ever: – Heard the sirens, but not known where they were coming from? – Been taken by surprise by an emergency vehicle and not had time to get out of the way? – Not seen the lights or heard the siren until they are right behind you? Then you understand the need for a more advanced warning system that can save time and lives. EVADE: Emergency Vehicle Alert Device Motivation: The group was struck by the fact that more and more frequently emergency vehicles are not seen or are simply ignored by drivers on the road. This could be caused by better insulation that makes cars quieter, larger vehicles on the road creating a visual obstruction, or by increased distractions on the road like cell phones and loud music. In order to overcome these obstacles, an advanced alert system is needed that does not rely on line-of-sight or sirens and has the capability of capturing the driver’s attention. EVADE: Emergency Vehicle Alert Device Goals: The objective of the emergency vehicle alert device is to surpass the current obstacles for alerting drivers by transmitting a signal from the emergency vehicle that will be picked up by cars. This signal will trigger a visual alert to inform the driver what type of vehicle is approaching and from what direction. Simultaneously, the signal will quiet the interior of the car and play an audible alert message in both English and Spanish. EVADE: Emergency Vehicle Alert Device Basic Objectives: EAT - Emergency Alert Transmitter: • Transmission begins simultaneously with lights and sirens • Sends GPS and compass headings to determine approach direction. • Transmission radius is large enough to provide the desired advanced alert. • Does not inhibit normal vehicle operation or require extra work from driver. • Does not put unusual strain on other vehicle components or battery. EVADE: Emergency Vehicle Alert Device Emergency Alert Transmitter Block Diagram: HEC 8-BIT CONNECT TO EXISTING SWITCH THAT TURNS ON EMERGENCY LIGHTS. 1 3 J COMPASS SIGNAL POWER POWER IGNITION TOD TCU 8-BIT SIGNAL 3 D J 8-BIT SIGNAL 1 MEMORY POWER (IF REQ'D) _ + _ PCM 3 ETD D 3 EMERGENCY VEHICLE BATTERY 1 (POWER SUPPLY) J 8-BIT SIGNAL + AUTOMOBILE ANTENNA 1 3 J 1 EVADE: Emergency Vehicle Alert Device Basic Objectives: EAR - Emergency Alert Receiver: • Automatically detects signal and alerts driver during normal operation. • Allows normal operation of vehicle when signal not detected • Shuts down stereo and plays audible alert message until vehicle is out of range, then resumes normal operation. • Displays direction of approach to driver on a physical display screen. • Uses low power that will not affect other systems in the car or strain battery supply levels. EVADE: Emergency Vehicle Alert Device Emergency Alert Receiver Block Diagram: EVADE: Emergency Vehicle Alert Device Project Management Flowchart: Write Complete Project Document Beginning Beginning of of Senior Senior Design I Design I Develop Develop Functional Functional Requirements Requirements & & Block Diagram Block Diagram Research Research Possible Possible Implementations Implementations Joshua: Joshua: Hall Hall Effect Effect Compass Compass GPS GPS Sensor Sensor Transmitter Transmitter & & Receiver Receiver Derrick: Derrick: Audio Audio Bypass Bypass Unit Unit Power Power Control Control Unit Unit Legal Restrictions Legal Restrictions Chuck: Chuck: Recorded Recorded Messages Messages Visual Visual Display Display PCB PCB Diagrams Diagrams Proposed Proposed Design Design Created Created with with Schematics Schematics Build Build prototype prototype Not Working Test Test Prototype Prototype for for Correct Correct Functionality Functionality Properly Functioning Stephen: Stephen: Transmitter Transmitter Control Control Unit Unit Receiver Receiver Control Control Unit Unit Programming Programming Present Present Final Final Design Design & & Complete Senior Design Complete Senior Design IIII Subsystem #4 - Derrick Nelson TOD – Turn-On Device PCM – Power Control Module RAA – Recorded Audible Alert SBU – Switching Bypass Unit EVADE: Emergency Vehicle Alert Device Turn-On Device: •Controls power flow to components to reduce waste heat •TOD(EAT) – simple switch connected to emergency lights, interfaces with transmitter •TOD(EAR) – software implementation in RCU, interfaces with RAA Emergency Alert Transmitter Emergency Alert Receiver EVADE: Emergency Vehicle Alert Device PCM Design Objectives: •Operate on standard 12V vehicle power •Provide multiple voltage levels for various components •Provide clean source of power for transmitter and receiver: must not introduce radio frequency interference (RFI) •Both PCMs operate whenever vehicle is running, TOD responsible for limiting power consumption •Design Decision – linear vs. switching regulators • Cost, efficiency/heat, noise EVADE: Emergency Vehicle Alert Device Power Specifications: EAT (Transmitter) EAR (Receiver) Item Voltage (V) Current Line (mA) PIC 1.8 – 3.6 250 3.3 Transmitter 1.8 – 3.6 12.5 3.3 GPS 3.3 50 3.3 HEC 8 – 13 10 3.3 Total Current (mA) 322.5 Item Voltage (V) Current (mA) Line GPS 3.3 50 3.3 HEC 8 – 13 10 3.3 PIC 1.8 – 3.6 250 3.3 RAA 2.5 - 5.5 20 3.3 Receiver 4.8 – 5.5 3 5 5 28 5 2.7 – 5.5 2 5 5 400 5 SBU VDU controller VDU display Total Current (mA) 330 433 EVADE: Emergency Vehicle Alert Device Voltage Regulators: •3 regulators used to achieve the required voltage levels • All Low Drop-Out voltage for efficiency • Very clean output voltages LD2908050 (5.0 V, 800 mA, STMicro.) TPS79633 (3.3 V, 1A, TI) TC1107 (3.3 V, 300 mA, Microchip) •Vin: 12V, filtered •Vout: 3.3 and 5V; filtered •Current Limits: Well above spec. EVADE: Emergency Vehicle Alert Device SBU Design Objectives: •Cause no distortion of stereo signal when EVADE not in use •Completely and cleanly bypass stereo signal when in use •Must operate whether the stereo system is in use or if it is off EVADE: Emergency Vehicle Alert Device Signal Bypass: •Bypass accomplished w/ electromechanical relays ( 1 per speaker) • TX2-5 (Panasonic) • 4 ms switching speed • Max Ratings: 60 W, 2 A •Simple interface with the vehicle’s speaker wires EVADE: Emergency Vehicle Alert Device Recorded Audible Alert (RAA): The RAA alerts the driver to the presence of an emergency vehicle by playing an audio message through the vehicle’s speakers. RAA Design Objectives: •Generate alert messages in English and Spanish • Pre-recorded, or • Speech synthesizer •Determine correct message to be played •Send message to SBU and trigger bypass EVADE: Emergency Vehicle Alert Device Recorded Audible Alert: •Nuvoton ISD1760 ChipCorder • Voice record and playback, storage on internal Flash memory • Stand-alone and SPI modes • No need for external audio amplifier •Atmel Atmega328 • • • • Low-power 8-bit microcontroller 32KB Programmable Flash SPI interface with ISD1760 Programmed on Arduino Uno development board EVADE: Emergency Vehicle Alert Device RAA Operation: Subsystem #2 - Joshua Guinn HEC/GPS – Hall Effect Compass & GPS ETD – Emergency Transmission Device EVADE: Emergency Vehicle Alert Device HMC 6352 Electronic Compass Supply Voltage = 2.7 to 5.2 V Heading Accuracy = 2.5 deg Operating Temp = -20 to 70ºC Size = 6.5 x 6.5 x 1.5 mm Weight = 0.14 grams I2C Serial Interface EVADE: Emergency Vehicle Alert Device The heading, output data, will be a value in tenths of degrees from zero to 359.9, N = 0, and provided in binary format over two bytes. These two bits will then give our eight cardinal directions. N > 337.5 OR <= 22.5 NE > 22.5 AND <= 67.5 E > 67.5 AND <= 112.5 SE > 112.5 AND <= 157.5 S > 157.5 AND <= 202.5 SW > 202.5 AND <= 247.5 W > 247.5 AND <= 292.5 NW > 292.5 AND <= 337.5 EVADE: Emergency Vehicle Alert Device GPS Modules researched General Characteristics GlobalSAT EM-408 Modulstek MG-S01SP Antenova M10214-A1 Receiver Architecture 20 channels 1 satellite / channel L1 1575.42 MHz 1.023 MHz chip rate 20 channels 1 satellite / channel L1 1575.42 MHz 1.023 MHz chip rate 20 channels 1 satellite / channel L1 1575.42 MHz 1.023 MHz chip rate Antenna Built-in or External Built-in Built-in Data Output Protocol SiRF Binary NMEA 0183 NMEA 0183 SiRF Binary NMEA 0183 Dimensions 36.4 x 35.4 x 8.3mm with antenna 19.0 x 19.0 x 6.5mm antenna 18 x 18 x 2mm 43 x 9 x 4mm with antenna EVADE: Emergency Vehicle Alert Device GlobalSAT Tecnology Corporation EM-408 EVADE: Emergency Vehicle Alert Device GPS Output Protocol NMEA 0183 •NMEA “National Marine Electronics Association” •The NMEA 0183 standard uses a simple ASCII, serial communication protocol. •Data is transmitted at 4800 baud rate through UART. •Data is transmitted in sentences. •GGA ($GPGGA) GPS Position, Time And Fix. $GPGGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh EVADE: Emergency Vehicle Alert Device Performance Characteristics •Maximum altitude 18,000 m •Maximum velocity 545 m/s •Maximum acceleration 4g •Position accuracy 2.5 m •Acquisition rate < 35 sec cold start < 1 sec hot start EVADE: Emergency Vehicle Alert Device Power and Environmental Specifications •Power supply 3.3 to 5.5 V DC •Main supply current Acquiring 50 mA Tracking 30 mA •Operating temperature -20 to 85ºC •Storage temperature -40 to 85 ºC •Relative humidity 5 to 95 % EVADE: Emergency Vehicle Alert Device Transmitters Researched •MICRF 113 •TXM-433-LR-S •PD 5000 EVADE: Emergency Vehicle Alert Device Operating Ratings •Supply voltage 2.1 to 3.6 V •Output power -4 to 4 dBm •Operating temperature -40 to 85 ºC •Transmitter frequency 433 MHz •Data rate 10 kbps EVADE: Emergency Vehicle Alert Device TXM-433-LR-S Operating diagram Pin Name GND Data GND LADJ/VCC PDN VCC GND ANT Pin Description Ground Data input Ground Output power level adjust Power down Supply voltage Ground 50 ohm RF output EVADE: Emergency Vehicle Alert Device Recievers researched •MICRF002YM •RMX-433-LR-S •PD 5000 EVADE: Emergency Vehicle Alert Device Operating Ratings •Supply voltage 2.7 to 3.6 V •Receiver sensitivity -112 dBm •Operating temperature -40 to 70 ºC •Receiver frequency 433 MHz EVADE: Emergency Vehicle Alert Device RXM-433-LR-S Operating diagram Pin Number Pin Name 4 GND Ground 5 VCC Pin Description 6 PDN 7 RSSI Supply voltage Power down Received signal strength indicator 8 DATA Data Output (Digital Output) 15 GND 16 ANT Ground 50 ohm RF output Subsystem #3 - Stephen Watson TCU – Transmitter Control Unit RCU – Receiver Control Unit EVADE: Emergency Vehicle Alert Device Function of the Transmitter Control Unit: The transmitter control unit is essentially the brains behind the entire transmitter. It serves as the central hub that collects the information from the GPS and Hall effect compass and condenses the positional information as well as the vehicle type into a single signal which is broadcast to the receiver. The transmitter control unit is also required to create the time delays between transmissions so that signals do not overlap. EVADE: Emergency Vehicle Alert Device Block Diagram of Transmitter Control Unit: GPS UART PIC Controller Compass 3 Bits Transmitted Signal To Transmitter for Modulation EVADE: Emergency Vehicle Alert Device Controller Selection: Research narrowed the choice of controller to a FPGA or PIC microcontrollers. With limited testing, PIC controllers were selected as the controller of choice. Reasons for Choosing PIC: • Simplified programming in C • Very inexpensive (free samples) • Easy to use serial protocol • Numerous guides and sample code to assist with programming and debugging EVADE: Emergency Vehicle Alert Device Programming Flowchart: Unit is turned on Switch Flipped On? Yes No Run Loop For Delay Between Transmissions Read GPS Position to Memory Combine Latitude, Longitude, Compass Bits Into Single Signal Output Signal to Transmitter for Modulation EVADE: Emergency Vehicle Alert Device Transmission Delay: • For a speed of 45 mph: 45 mph => 66 ft/sec • For a one second delay: 66 ft/sec x 1 sec = 66 ft • With the allowable test range by the FCC, this is the best delay period between transmissions. EVADE: Emergency Vehicle Alert Device Transmitted Data Format: Security Code Compass Latitude Longitude 5 Bytes 2 Bytes 8 Bytes 9 Bytes • The total number of bytes to transmit is well below the limit of the transmitter and receiver. EVADE: Emergency Vehicle Alert Device Function of the Receiver Control Unit: The receiver control unit is the most fundamental processing unit of the entire project. As the central control unit, it is required to receive the demodulated transmission signal and properly extract the information. After storing this information, the receiver control unit must compare the positional information of the emergency vehicle with its own GPS coordinates and compass heading to determine if the vehicle paths will intersect and from what direction the emergency vehicle is approaching. The receiver control unit must then initiate the visual and audible alert systems. EVADE: Emergency Vehicle Alert Device Block Diagram of Receiver Control Unit: GPS Compass UART 3 Bits Antenna & Transmitted Signal Demodulator 5 Bit Alert Code Recorded Audible Alert 5 Bit Alert Code Visual Display Unit PIC Controller EVADE: Emergency Vehicle Alert Device Directional Calculations: In order to calculate the direction of the car relative to the emergency vehicle, the latitude (x value) and longitude (y value) for the emergency vehicle are subtracted from the latitude and longitude of the car. Based on the whether the coordinates are +/-, the compass direction is used to determine if the vehicles will intersect. This is also used to determine the direction the emergency vehicle is approaching relative to the car. Subsystem #4 - Charles Logan VDU – Visual Display Unit PCB Design EVADE: Emergency Vehicle Alert Device VDU Visual Display Unit (VDU) • 16x4 dot matrix LCD • Display heading under normal operation • Small size – mountable in dash. EVADE: Emergency Vehicle Alert Device LCD Schematic RCU Hitachi HD44780 LED R PIN 2 •The LCD Display will be driven by the Hitachi HD44780 LED 8/1 R LED 14/8 R LED 5V •Signal for the LED’s obtained from the RCU R LED R LED R LED PIN 1 R LED R EVADE: Emergency Vehicle Alert Device LCD2 PCM RCU PIC Hitachi HD44780 RS R/W E DB0-DB7 Segment Driver SEG 1-40 COM 1-16 COM 17-32 SEG 41-80 Segment Driver SEG 80-160 EVADE: Emergency Vehicle Alert Device VDU-LED Visual Display Unit (VDU) Under emergency conditions, an LED will blink to alert the motorist of the direction the emergency vehicle is approaching EVADE: Emergency Vehicle Alert Device VDU-LED Printed Circuit Board (PCB) Design • Created using PCB Artist software for creating the fab, pcb, and dxf files necessary to create a printed circuit board. • Created by Advanced Circuits (4pcb.com) EVADE: Emergency Vehicle Alert Device VDU-LED Sample PCB Diagrams from RAA .pcb File Design Schematic Design EVADE: Emergency Vehicle Alert Device VDU-LED Final Prototypes: Emergency Alert Transmitter Emergency Alert Receiver EVADE: Emergency Vehicle Alert Device VDU-LED Testing: • • • • • MPLAB Simulations Serial tracing Distance testing Lots of breadboards Even running wire down 4 floors & half-way round Engineering 1 EVADE: Emergency Vehicle Alert Device Budget: Module Quantity Expected Cost Actual Cost Antenna 2 $20 $20 Car Stereo & Speakers 1 Donated Donated Transmitter 1 $30 $60 Compass & GPS 2 $40 $165 Power Supply 2 $50 $30 Recorded Audio Chips 1 Sampled $30 Microcontollers 2 $180 $60 PCB 1 $100 $180 Display Screen and LEDs 1 $30 $80 $100 $100 Incidentals Expected Total Cost: $530 Total Expected Cost ( 2X Buffer) $1060 Actual Cost $705+ EVADE: Emergency Vehicle Alert Device Milestones: Tasks Choose Project Develop Specs Research Documentation Order Parts Test Subsystems First Prototype Mid-term Demo Scenario Testing Final Prototype Present Project GRADUATE! Jan. Feb. Mar April May June July Aug Sept Oct Nov Dec EVADE: Emergency Vehicle Alert Device Questions?
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