multi-sensor array (version 4)

127 Pages·2013·3.75 MB·English

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
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Figure 1: 28 July 2013 :Balloon Bonanza Test Flight
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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
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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
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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 .................................................................................................................. 125
Concept Document .................................................................................................. 125
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List of Figures
Figure 1: 28 July 2013 :Balloon Bonanza Test Flight ...................................................... 3
Figure 2: MSAv4 Block Diagram ................................................................................... 19
Figure 3: Raspberry Pi (Model B - Version 1) ................................................................ 20
Figure 4: System Interface Daughterboard ................................................................... 22
Figure 5: External Controls and Indicators Board .......................................................... 23
Figure 6: External Sensors Board ................................................................................. 24
Figure 7: RPi GPIO Pin Out and P1 Header with Numbering Source: elinux.org(2012) 29
Figure 8: ECIB Board Plan (Front View) ........................................................................ 31
Figure 9: SID Mounted to RPi (Shown up-side down for visibility) ................................ 34
Figure 10: External Power Supply Rails ........................................................................ 35
Figure 11: External I2C Bus Connections ..................................................................... 36
Figure 12: ADC Circuit and External Connections ........................................................ 36
Figure 13: SID Pushbutton and LED ............................................................................. 40
Figure 14: MSAv4 Internal Enclosure (Outside View) ................................................... 40
Figure 15: MSAv4 Internal Enclosure (Inside View) ...................................................... 41
Figure 16: MSAv4 Flight Box (Front View) .................................................................... 42
Figure 17: MSAv4 Flight Box (Top View) ...................................................................... 42
Figure 18: MSAv4 Flight Box with Particle Sensor ........................................................ 43
Figure 19: MSAv4 Flight Box with Particle Sensor System ........................................... 43
Figure 20: Main Loop Flowchart .................................................................................... 48
Figure 21: Scheduling Thread Flowchart (Top Level) ................................................... 51
Figure 22: HARBOR Environmental Chamber .............................................................. 65
Figure 23: MPXM2102A Linear Pressure Range .......................................................... 66
Figure 24: MPXM2102A Non-Linear Pressure Range................................................... 66
Figure 25: MPXM2102A Reconstructed Pressure ......................................................... 67
Figure 26: MSAv4 vs. Weather Station Humidity .......................................................... 68
Figure 27: MSAv4 Magnetic Axis Orientation ................................................................ 69
Figure 28: Magnetometer Test Results ......................................................................... 70
Figure 29: Accelerometer/Gyroscope Axis Orientation.................................................. 71
Figure 30: Accelerometer Test Results ......................................................................... 72
Figure 31: MSAv4 Particle Sensor Readings vs. Altitude 28 July, 2013 ....................... 74
Figure 32: Landing Site in La Pointe, Utah 28 July, 2013 .............................................. 74
Figure 33: MSAv3 and MSAv4 Internal Temperature vs. Time 31 July, 2013 ............... 75
Figure 34: MSAv4 External Temperature and Altitude vs. Time 31 July, 2013 ............. 76
Figure 35: Landing Point in La Pointe, Utah 31 July, 2013 ............................................ 77
Figure 36: System Interface Daughterboard Schematic ................................................ 81
Figure 37: System Interface Board Layout (Top) .......................................................... 82
Figure 38: System Interface Board Layout (Bottom) ..................................................... 82
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Figure 39: External Sensor Board Schematic ............................................................... 83
Figure 40: External Sensor Board Layout ..................................................................... 84
Figure 41: External Controls and Indicators Board Schematic ...................................... 85
Figure 42: External Controls and Indicators Board Layout (Top View) .......................... 86
Figure 43: External Controls and Indicators Board Layout (Bottom) ............................. 86
Figure 44: GPS Interface Board Schematic .................................................................. 87
Figure 45: GPS Interface Board Layout (Top View) ...................................................... 88
Figure 46: GPS Interface Board Layout (Bottom View) ................................................. 89
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List of Tables
Table 1: XR20M1280 LSR Register Map ...................................................................... 33
Table 2: Supply Current for Standard Equipped 3.3V Devices ...................................... 35
Table 3: MSAv4 Internal Enclosure Parts and Dimensions ........................................... 41
Table 4: Power Management 1 Register ....................................................................... 55
Table 5: MPU6000 Clock Source Configurations .......................................................... 55
Table 6: MPU6000 Configuration Registers .................................................................. 56
Table 7: Gyroscope Full Scale Settings ........................................................................ 56
Table 8: Accelerometer Full Scale Settings ................................................................... 56
Table 9: Accelerometer Data Registers......................................................................... 56
Table 10: HMC5883 Data Output Registers .................................................................. 57
Table 11: HMC5883 Register List ................................................................................. 57
Table 12: Mass Comparison of MSAv3 vs. MSAv4 ....................................................... 61
Table 13: Power Consumption Comparison of MSAv4 vs. MSAv3 ............................... 62
Table 14: MSAv4 Parts List Core Build with SID and Sensor Board ........................... 123
Table 15: MSAv4 Parts List External Controls and Indicators Board .......................... 124
Table 16: MSAv4 Parts List GPS Interface Board ....................................................... 124