MULTI-SENSOR ARRAY (VERSION 4) 1 MULTI-SENSOR ARRAY (VERSION 4) Design Document Team: Michael Petersen Jen Stoddard Wesley Mahurin Project: MSAv4 Date Prepared: November 20, 2013 MULTI-SENSOR ARRAY (VERSION 4) 2 This page is intentionally blank MULTI-SENSOR ARRAY (VERSION 4) 3 Figure 1: 28 July 2013 :Balloon Bonanza Test Flight MULTI-SENSOR ARRAY (VERSION 4) 4 This page is intentionally blank MULTI-SENSOR ARRAY (VERSION 4) 5 Table of Contents List of Figures .................................................................................................................. 8 List of Tables ................................................................................................................. 10 Revision History ............................................................................................................ 11 List of Abbreviations and Definitions ............................................................................. 12 1.0 Introduction ............................................................................................................. 13 2.0 Scope ...................................................................................................................... 13 3.0 Design Overview ..................................................................................................... 14 3.1 Requirements ....................................................................................................... 14 3.1.1 Primary Project Goals ................................................................................... 14 3.1.2 Functional Requirements .............................................................................. 15 3.1.3 Performance Requirements .......................................................................... 15 3.1.4 Interface Requirements ................................................................................. 15 3.1.5 Environmental Requirements ........................................................................ 16 3.2 Constraints ........................................................................................................... 16 3.2.1 Cost ............................................................................................................... 16 3.2.2 Physical ......................................................................................................... 16 3.2.3 Scheduling .................................................................................................... 16 3.2.4 Safety ............................................................................................................ 16 3.3 Applicable Standards ........................................................................................... 17 3.3.1 I2C ................................................................................................................ 17 3.3.2 RS-232 .......................................................................................................... 17 3.3.3 ANSI-C .......................................................................................................... 17 3.4 Dependencies ...................................................................................................... 17 3.4.1 Power Supply ................................................................................................ 17 3.4.2 I2C Bus (BSC0) ............................................................................................. 17 3.5 Theory of Operation ............................................................................................. 18 3.5.1 Raspberry Pi ................................................................................................. 20 3.5.2 System Interface Daughterboard .................................................................. 21 MULTI-SENSOR ARRAY (VERSION 4) 6 3.5.3 External Controls and Indicators Board ......................................................... 23 3.5.4 External Sensor Board .................................................................................. 24 3.5.5 GPS Interface Module ................................................................................... 24 4.0 Design Details ......................................................................................................... 25 4.1 Raspberry Pi ........................................................................................................ 25 4.1.1 SSH and Setting Up the RPi Static IP Address for Communication .............. 25 4.1.2 Unlocking the I2C Bus and Using i2c-tools to Verify ..................................... 27 4.1.3 Unlocking the UART Pins and Using Mini-com to Verify ............................... 28 4.1.4 The Raspberry Pi GPIO Pins ........................................................................ 28 4.1.5 Conserving Power in Data Logging Mode ..................................................... 30 4.2 External Sensor Board ......................................................................................... 30 4.3 External Controls and Indicators Board................................................................ 30 4.4 GPS Interface Module .......................................................................................... 32 4.4.1 XR20M1280 ...................................................................................................... 32 4.5 System Interface Daughterboard ......................................................................... 33 4.5.1 Connecting the SID to the RPi ...................................................................... 33 4.5.2 Power Regulation .......................................................................................... 34 4.5.3 I2C Bus ......................................................................................................... 35 4.5.4 Analog to Digital Converter and External Sensors ........................................ 36 4.5.5 System Interface Daughterboard Sensors and Devices ................................ 37 4.5.6 Special Function Circuits ............................................................................... 39 4.6 MSAv4 Internal Enclosure .................................................................................... 40 4.7 MSAv4 Flight Box ................................................................................................ 42 4.8 Interface Software ................................................................................................ 44 4.8.1 Linux Scripts .................................................................................................. 45 4.8.2 MSAv4 Operational Flight Program ............................................................... 47 4.9 Design Concepts and Requirements not Completed for MSAv4 .......................... 59 5.0 Testing .................................................................................................................... 61 5.1 Lab Testing .......................................................................................................... 61 5.1.1 Dimension Requirement Testing ................................................................... 61 5.1.2 Performance Requirement Testing ............................................................... 61 MULTI-SENSOR ARRAY (VERSION 4) 7 5.1.3 Functionality Requirement Testing ................................................................ 63 5.1.5 Interface Hardware Testing ........................................................................... 72 5.2 Flight Testing ....................................................................................................... 73 5.2.1 Particle Sensor Guest Package Testing ........................................................ 73 5.2.2 Internal and External Temperature Readings ................................................ 75 5.2.1 Hardness Requirement Testing ..................................................................... 76 7.0 References .............................................................................................................. 79 Works Cited ................................................................................................................... 79 Appendix A .................................................................................................................... 80 Schematics ................................................................................................................ 80 Appendix B .................................................................................................................... 90 MSA_v4 Operational Flight Program ......................................................................... 90 GPS Code ................................................................................................................ 105 Appendix C .................................................................................................................. 107 C Code Libraries ...................................................................................................... 107 BCM2835 C Library .............................................................................................. 107 Appendix D .................................................................................................................. 123 Parts Lists ................................................................................................................ 123 Appendix E .................................................................................................................