Novel Magnetometers Flight Experiment

Conceptual Design Review - Draft

Boston University

Mag Dogs Team

December 3, 2008

Novel Magnetometers Flight Experiment - Science

• Design, assemble, and test two COTS, solid state 3-axis magnetometers with controller, data storage and power: – Honeywell HMR2003 - anisotropic magneto-resistance – Aichi Micro Intelligent AMI302 - giant magneto-impedance

• Compare directly the X,Y,Z flight readings of both magnetometers

• Measure EMI from the chips (Honeywell has bias straps and Aichi bias coils).

• Honeywell device was proposed for a University of Colorado small satellite design in 2003, but we have found no other evidence of its use in space flight.

• Aichi chip is under study by the US Navy for navigation of autonomous marine vehicles. We could find no record of the Aichi chip being used in space.

BU Magnetometers

Mont Alto

Controller

Power Launch safing

Data Card

A/DHoneywell

Aichi

G-switch

Subsystems

• Sensor 1 Aichi

• Sensor 2 Honeywell

• Power (Battery + Regulation)

• Controller– Sequencing of sensors– Data A/D conversion– Storage to SD card

Sensors – Aichi AMI302 MagnetometerSensors – Aichi AMI302 Magnetometer• Sensing technologySensing technology

– Based on MBased on Magneto-agneto-IImpedance mpedance effect of amorphous magnetic wireeffect of amorphous magnetic wire

• Range of measurable magnetic flux density: -2 to +2 gaussRange of measurable magnetic flux density: -2 to +2 gauss• 3 sensors for length, width, and height (X, Y, Z)3 sensors for length, width, and height (X, Y, Z)• Inputs and Outputs:Inputs and Outputs:

Unit: mm

NameName I/OI/O Pin #Pin # DescriptionDescription

CSCS InputInput 1010 Chip StandbyChip Standby

CH2CH2 InputInput 99X axis / Y axis / Z axis output switchingX axis / Y axis / Z axis output switching

CH1CH1 InputInput 88

OUTOUT OutputOutput 11 Linear DC output proportional to magnetic fieldsLinear DC output proportional to magnetic fields

Sensors – Aichi AMI302 MagnetometerSensors – Aichi AMI302 Magnetometer• Supply Voltage: -0.3 to +6.5 VDCSupply Voltage: -0.3 to +6.5 VDC• Maximum Supply Current: 200 mAMaximum Supply Current: 200 mA

– ApproximatelyApproximately 1% duty cycle on this 1% duty cycle on this peak currentpeak current

• Operating Temperature: -20 to +85°COperating Temperature: -20 to +85°C• Magnetic CharacteristicsMagnetic Characteristics

– Operating Test ConditionsOperating Test Conditions• Ambient Temperature: 25°CAmbient Temperature: 25°C• Power Supply: 3 VDCPower Supply: 3 VDC• 10 μF ceramic capacitor between Power 10 μF ceramic capacitor between Power

Supply and GroundSupply and Ground

PropertyProperty Min.Min. TypicalTypical Max.Max. UnitsUnitsOutput Offset Voltage at Zero Gauss

0.8 1.5 1.9 Volts

Sensitivity 0.16 0.24 0.38 Volts/gauss

Sensors - Honeywell HMC2003 Sensors - Honeywell HMC2003 MagnetometerMagnetometer

• Sensing technologySensing technology– Anisotropic magneto-resistanceAnisotropic magneto-resistance

• Range of measurable magnetic flux density: -2 to +2 Range of measurable magnetic flux density: -2 to +2 gaussgauss

• 3 sensors for length, width, and height (X, Y, Z)3 sensors for length, width, and height (X, Y, Z)– One output for each direction (Xout, Yout, Zout)One output for each direction (Xout, Yout, Zout)

Symbol MillimetersMax Min

A 10.92 11.94A1 2.92 3.42D 25.91 27.3e 2.41 2.67H 18.03 19.69

Sensors - Honeywell HMC2003 MagnetometerSensors - Honeywell HMC2003 Magnetometer

• Supply Voltage: 6 to 15 VDCSupply Voltage: 6 to 15 VDC• Maximum Supply Current: 20 Maximum Supply Current: 20

mAmA• Operating Temperature: -20 to Operating Temperature: -20 to

+85°C+85°C• Magnetic CharacteristicsMagnetic Characteristics

– Operating Test ConditionsOperating Test Conditions• Ambient Temperature: 25°CAmbient Temperature: 25°C

• Power Supply: 12 VDCPower Supply: 12 VDC

• Set/Reset switching is activeSet/Reset switching is active

PropertyProperty Min.Min. TypicalTypical Max.Max. UnitsUnitsNull Field Output 2.3 2.5 2.7VoltsSensitivity 0.98 1 1.02Volts/gaussOutput Voltage 0.5 4.5Volts

RCM4300 RabbitCoreRCM4300 RabbitCore• Stores up to 1GB of information with its miniSD memory cardStores up to 1GB of information with its miniSD memory card• Runs at 58.9MHz Runs at 58.9MHz • 20 parallel digital I/O lines 20 parallel digital I/O lines • 8 channel analog input with 12 bit resolution8 channel analog input with 12 bit resolution• Maximum asynchronous transfer rate =Clk (58.9MHz)/8Maximum asynchronous transfer rate =Clk (58.9MHz)/8• 4 PWM registers with 10 bit counter and priority interrupts4 PWM registers with 10 bit counter and priority interrupts

Input/Output:Input/Output:• 3 Inputs from Aichi - 3 Inputs from Aichi - X axis / Y axis / Z axis output from AichiX axis / Y axis / Z axis output from Aichi• 3 Inputs from Honeywell - 3 Inputs from Honeywell - X axis / Y axis / Z axis output from X axis / Y axis / Z axis output from Honeywell Honeywell

RCM4300 RabbitCore cont.RCM4300 RabbitCore cont.AichiAichi• Use timer to iterate outputs Use timer to iterate outputs • Iterate outputs from RabbitCore to obtain readings from different from differerent axes Iterate outputs from RabbitCore to obtain readings from different from differerent axes

channels on Aichichannels on Aichi• Different channels for x, y, and z axes Different channels for x, y, and z axes • Take input and pass through A/D converter from each Aichi channelTake input and pass through A/D converter from each Aichi channel• Store converted values onto SD flash memory for future useStore converted values onto SD flash memory for future use

HoneywellHoneywell• Use timer to constantly pull Honeywell for all x, y, and z axes simultaneouslyUse timer to constantly pull Honeywell for all x, y, and z axes simultaneously• Stores the data from each data on a separate place on the SD flash memoryStores the data from each data on a separate place on the SD flash memory• Each axes represents a separate output pin from chipEach axes represents a separate output pin from chip• Use A/D converter to store as value and store converted value on flashUse A/D converter to store as value and store converted value on flash

Science Experiment Timing

Start at Launch

Key:H - HoneywellA - AichiM - Memory(rabbit)EMI - Electromagnetic Interference

Normal 1 H A M 5 Mins

Normal 3 H A M 3 Mins

EMI 1 ~H A M 30 Sec

Normal 4 H A M 10 Mins

Normal 2 H A M 3 Mins

EMI 2 H ~A M 30 Sec

EMI 3~H ~A M 30 Sec

Safe ~H ~A ~M End

Test Experiment Timing

Start

Key:H - HoneywellA - AichiM - Memory(rabbit)EMI - Electromagnetic Interference

Normal 1 H A M 5 Sec

Normal 3 H A M 3 Sec

EMI 1 ~H A M .5 Sec

Normal 4 H A M 10 Sec

Normal 2 H A M 3 Sec

EMI 2 H ~A M .5 Sec

EMI 3~H ~A M .5 Sec

Safe ~H ~A ~M End

Data Flows

• 2 sensors, 4 data sources, housekeeping• 12 b/sample on Rabbit RCM4300• Slow change in Earth’s field over flight• Changes from spin of rocket (<10 Hz)• Sample 10 pts/cycle or 100 Sa/s• Estimated flight 22.5 min or 1350 s• 135k Sa x 4 x 12b/Sa = 6.48 Mb = 0.8MB• Well within low-end SD card capacities

Preliminary Schematics

HMC2003

AMI302-1Z-axis

AMI302-2X, Y axes

CH1 H

CH2 L

CH1

CH2

X axis

Y axis

Z axis

Enable CS

Power SwitchHMC302

PowerDown

12 V

Linear Regulator

12 V

Z axis

X, Y axis

DB37P-5

DB37P-8DB37P-7

DB25P-10

DB25P-16

DB25P-21

DB25P-22

DB25P-13

Enable CS

ResetDB25P-19

DB25P-6

Bridge

3.3V

3.3V

Testing

• Electrical systems operation– Timing test for sequencing– DAQ test with sensors– SD card storage and retrieval

• Sensor operation– Earth field testing– Helmholz coil testing of boards

• Power operation– Charging/discharging– Voltage regulation and distribution

Parts & Vendors• Aichi AMI302 (3 on hand from Aichi; two

week order time)

• Honeywell (2 on hand; distributors; 2 week order time)

• PCB turnaround (5 business days)

• PCB Assembly for Aichi (10 business days)

• Rabbit Core 4300 (Dev kit on hand)

• Miscellaneous DigiKey/Newark parts

RockSat Payload Canister User Guide Compliance

• Sensor board ~15 cm x 15 cm x 2 cm; < 150 g

• Rabbit board ~ 5 cm x 8 cm x 1 cm; <100 g• Battery ~ 6 cm x 10 cm x 2 cm; <150 g• (Easily reside in ½ canister or even ¼

height) • Will follow G-switch and Rocket wire

protocol• Independent of PSMA system

Shared Can Logistics Plan

• Penn State Mont Alto - Boston University

• Each system is independent• Structural interfacing (PSMA)

BU Volume

Battery volume

Rabbit uP Sensors

M. Ruane

RockSat Student Launch – Mag Dogs, Boston University

Conceptual Use of BU Volume

SIZE FSCM NO DWG NO REV

BURS-2008-01 1.0

SCALE 1/2 : 1 3-Dec-08 SHEET 1 OF 1

ManagementDr. Michael RuaneProfessor, ECE Dept., Boston University8 St. Mary's Street, Boston, MA 02215Phone: 617-353-3256 617-353-6440 faxE-Mail: mfr@bu.edu

Dr. Siegfried HerzogPenn State University at Mont Alto Assistant Professor of Mechanical Engineering 1 Campus Drive Mont Alto, PA 17237 Tel (717)-749-6209    Fax (717)-749-6069 E-Mail: hgn@psu.edu

BU Student Teams

• Sensors – Aichi – Shawn Doria

• Sensors – Honeywell – John Gancarz

• Power – Tracy Thai

• Rabbit Controller – Andy Lee

• Mechanicals – Jim Thumber

• Software/Simulations/Analysis – TBD– Nanosat teams join after January 15

BudgetItem Description Cost

1 Aichi AMI302 (3 in hand, one needed) $1002 Honeywell HMR2300 (2 in hand) (sensor <$100) $1003 Controller and miscellaneous ICs, discretes $2004 PCB fabrication $3005 PCB assembly of surface mount elements (flight board) $5006 Wire harness, connectors, miscellaneous $1007 NSROC payment for launch free8 Travel for integration, launch workshop June 2009 $20009 Contingency $1000

Total Cost $4300

• Conclusions

– BU Mag Dogs Team is closing out its semester and catching up

to the RockSat schedule– We have an enthusiastic group of students, a lab space for work,

and a Nanosat team becoming available in January– Our experiment is building on a sensor board from USERS and

a microcontroller DAQ system