Senior Design 2 Final Report December 6, 2016 AirBud Auto Fixed Base Operator Department of Electrical Engineering and Computer Science University of Central Florida Dr. Lei Wei Sponsored by: Michael F. Young and MacAvionics Group 4 Jordan Ruhl (Project Manager) [email protected] CE Carmen Henriquez Rojas [email protected] EE Mason Maines [email protected] CE Francisco Galue [email protected] EE Table of Contents 1 Executive Summary ....................................................................................... 1 2 Project Description ........................................................................................ 2 2.1 Project Justification and Motivation ......................................................... 2 2.2 Goals and Objectives .............................................................................. 2 2.2.1 Wind Conditions Report .................................................................... 2 2.2.2 Transmit Radio Check ...................................................................... 3 2.2.3 Artificial Intelligence .......................................................................... 3 2.2.4 Printed Circuit Board (PCB) Interface ............................................... 3 2.2.5 Web Interface ................................................................................... 4 2.3 Product Specifications ............................................................................. 5 2.4 System Description.................................................................................. 6 2.4.1 Power Supply .................................................................................... 6 2.4.2 VHF Aircraft Radio ............................................................................ 6 2.4.2.1 Avionics Communication Standards ........................................... 7 2.4.3 Interface Board ................................................................................. 7 2.4.4 Microprocessor ................................................................................. 7 2.4.5 Anemometer and Wind Vane ............................................................ 8 2.4.6 Monitor and Keyboard ....................................................................... 8 2.5 Design Constraints and Standards .......................................................... 8 2.5.1 Time Constraints ............................................................................... 8 2.5.2 Budget Constraints ........................................................................... 8 2.5.3 Related Standards ............................................................................ 8 2.5.3.1 USB ............................................................................................ 9 2.5.3.2 SPI ............................................................................................. 9 2.5.3.3 WAVE File .................................................................................. 9 2.5.3.4 Pulse Code Modulation ............................................................ 10 2.5.3.5 Radio Communication Phraseology/Techniques – P-8740-47 . 10 2.5.3.6 Traffic Advisory Practices at Airports Without Operating Control Towers – 90-42F ...................................................................................... 11 3 Background Information .............................................................................. 12 3.1 Existing Products ................................................................................... 12 3.2 Main Control Unit ................................................................................... 13 3.2.1 MCU Options and Selection ............................................................ 13 3.2.1.1 Arduino Uno ............................................................................. 13 3.2.1.2 Raspberry Pi 3 Model B ........................................................... 13 3.2.1.3 MCU Selection ......................................................................... 14 i 3.2.2 Communication Protocols ............................................................... 14 3.2.2.1 Push-to-Talk ............................................................................. 15 3.2.2.2 TX Signal .................................................................................. 15 3.2.2.3 RX Signal ................................................................................. 16 3.2.2.4 Carrier Detect ........................................................................... 16 3.2.2.5 Automatic gain control (AGC) ................................................... 16 3.2.3 Tapping into the Radio .................................................................... 16 3.2.4 Language Options and Selection .................................................... 18 3.2.4.1 MCU ......................................................................................... 18 3.2.4.2 Web Server .............................................................................. 19 3.2.5 Text-to-Voice Software ................................................................... 23 3.3 Interfaces ............................................................................................... 24 3.3.1 To Radio ......................................................................................... 24 3.3.1.1 TX Audio................................................................................... 24 3.3.1.2 PTT .......................................................................................... 24 3.3.2 From Radio ..................................................................................... 25 3.3.2.1 RX Audio .................................................................................. 25 3.3.2.2 Carrier Detect ........................................................................... 25 3.3.2.3 Automatic Gain Control ............................................................ 25 3.3.3 From Microcomputer ....................................................................... 25 3.3.3.1 PTT .......................................................................................... 26 3.3.3.2 TX Audio................................................................................... 26 3.3.4 To Microcomputer ........................................................................... 27 3.3.4.1 SPI Bus .................................................................................... 27 3.3.4.2 Carrier Detect ........................................................................... 28 3.3.5 From Anemometer .......................................................................... 28 3.3.5.1 Wind Speed .............................................................................. 29 3.3.5.2 Wind Direction .......................................................................... 29 3.4 Power .................................................................................................... 29 3.4.1 Voltage Source ............................................................................... 29 3.4.2 DC to DC Converters ...................................................................... 29 3.4.2.1 3.3V Regulators ........................................................................ 29 3.4.2.2 5V Regulators ........................................................................... 30 3.4.2.3 12V Regulators ......................................................................... 31 3.4.2.4 -12V Voltage Inverter ............................................................... 32 ii 4 Interface Board Design ................................................................................ 34 4.1 Power .................................................................................................... 35 4.2 SPI Bus ................................................................................................. 35 4.3 PTT Circuit ............................................................................................ 35 4.3.1 PTT Circuit Design .......................................................................... 36 4.3.2 PTT Circuit Design Final Changes .................................................. 36 4.4 Carrier Detect ........................................................................................ 37 4.4.1 Comparator Circuit .......................................................................... 37 4.4.2 Operational Amplifiers ..................................................................... 39 4.5 TX Audio Circuit .................................................................................... 41 4.5.1 Audio Compression Circuit ............................................................. 43 4.5.2 Audio Conditioning Circuit ............................................................... 46 4.5.3 TX Audio Conditioning Circuit (Final Revision) ............................... 46 4.6 RX Audio Circuit .................................................................................... 48 4.6.1 Audio Conditioning Circuit ............................................................... 49 4.6.2 Low Pass Filter Circuit .................................................................... 50 4.6.3 RX Audio Circuit Final Revision ...................................................... 50 4.7 Automatic Gain Control Voltage ............................................................ 51 4.7.1 Conditioner Circuit .........................................................................