Microbial Detection Arrays

Critical Design ReviewDecember 5th, 2006

Aerospace Senior ProjectsUniversity of Colorado – Boulder

Advisors: Dr. Forbes and Dr. MaslanikCustomers: BioServe and Tufts University

Jeff ChildersDave Miller

Elizabeth NewtonTed Schumacher

Shayla StewartSteven To

Charles Vaughan Sameera Wijesinghe

2

Briefing Overview• Overview of Objectives and

Requirements• System Architecture• Prototype Results• Mechanical Design Elements• Electrical Design Elements• Software Design Elements• Integration, Verification, and Test Plan• Project Management Plan • Appendices

3

Objectives

• Component of larger project– Future Mars astrobiology mission from

BioServe/Tufts University/JSC– Astrobiology objective: electrochemical sensing of

metabolic activity– Three components: biology (JSC), sensors

(Tufts), instrument hardware (CU)• MiDAs team objective: instrument hardware

component– Design/build integrated field instrument with

meaningful biological and spaceflight constraints– Validate key functions to enable field research – Extends proof-of-concept from lab to field

• Raise TRL from 1-3 to 4-5

4

TRL Objective

https://www.spacecomm.nasa.gov/spacecomm/programs/technology/default.cfm

5

Deliverables

• Field-ready unit (TRL 4-5)

• Test data that verifies requirements

• Operational manual for use

• Document proposing design solutions to further raise the TRL (to 6-7)

6

Requirements Overview1. Samples placed in

autoclaves2. Autoclaves heated to 121°C

and held for 15 minutes3. Autoclaves cooled to 20°C

and held for 24 hours4. Process may be repeated up

to 3 times5. Valves opened6. Water pumped into

autoclaves7. Sample flushed into reaction

chambers8. Inoculation sample added to

test chamber9. Environmental chamber

maintained between 4°C and 37°C

10. Mixers stir sample and water11. Sample is tested for 14 days

Water tubing not shown

7

Requirement Refinement

• Complete autonomy no longer primary goal– Increased reliance on experimenter to open valves

and deliver inoculation sample– Instrument will not provide its own power

• Reason: – Change at request of customer – trades autonomy

for reliability in field instrument– Autonomy adds expense, complexity, and failure

modes without proving key concepts or raising TRL – Autonomy options will be included in design

document– Key components maintained in field instrument

8

Mars/Earth ComparisonTheoretical Mars Mission MiDAs Earth Based Apparatus

Receive low power from Rover Receive low power from external source

Receive startup command from uplink Press power button

Rover opens Autoclave lid Person opens Autoclave lid

Rover inputs sample Person inputs sample

Rover closes Autoclave lid Person closes Autoclave lid

Autoclave cycle begins Autoclave cycle begins through SW run command

Rxn chamber environment controls begin Rxn chamber environment controls begin

Valve opens Person opens valve

Water flushes sample out of autoclave Water flushes sample out of autoclave

Valve closes Person closes valve

Mixing begins Mixing begins through SW run command

DAq begins DAq begins through SW run command

Inoculation sample added Person adds inoculation sample

DAq runs for 14 days DAq runs for 14 days

Data downlink from rover to satellite to Earth Data stored on-board, transfer to PC

9

System Architecture (External)

Dimensions: 18” x 18” x 15”

(46 cm x 46 cm x 39 cm)

10

System Architecture (Internal)

16” (40 cm)

10” (25 cm)

15”

(39

cm)

11

Mass Analysis

2 Autoclaves 1890g

4 TECs 720g

2 Pumps 127g Water Chamber

132g

Insulation 9.83g

2 Valves 1450g

Tubing 396g

2 Reaction Chambers 173g

Environmental Chamber 656g

2 Mixers 95.8g

Chassis 1150g

CPU and DAq (not shown)

292g

Sensors (not shown)

10.0g

Internal Mass: 7.10kg (15 lbs)

Total Mass: 13.90 kg (30 lbs)

12

2 weeks+ 27 to 75 hr 25.5 hr

27 hr1.5 hr 3 hr

Experiment Timeline

Soil

Start Finish

Soil Soil

t=0 Insert sample manually ___A B___Heater A: Heater B:Cooler A: Cooler B:Cycle A: Cycle B:

t1

S --

t2

-- S

t3

-- --

030 s

t4

F* --

t5

** F*

49.5 hr 51 hr

73.5 hr 75 hr

Autoclavet6,7,8,9

**optionalCan repeat two more times

t6 Reaction ___A B___Heater A: Heater B:Cooler A: Cooler B:

Soil

A B

13

Electrical Overview

KEY

14

Autoclave Prototype

• Concerns:– Low power heating– Seals

•304 Stainless Steel•Height = 2.25 in.•Inner Diameter = 1.5 in•LabView•External temperature sensor•Internal pressure sensor

15

Prototype Thermal Analysis

• Steady state 2W energy loss

• Heater on flat area

• Large thermal gradient

16

Autoclave Prototype Results

• Results: – 121 C for small 12W strip

heater, higher pressure than expected

– Very uneven heating– Seals held

0

5

10

15

20

25

30

35

0 20 40 60 80 100 120 140

time (min)

pres

sure

(psi

)

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

time (min)

tem

pera

ture

(deg

C)

•Conclusions:− 3 smaller strip heaters

evenly spaced−TEC used only for cooling−O-ring seals were effective−Melamine insulation was

effective

17

Mixing Prototype

• Ultrasonic– Frequency function of tip length– 18 kHz not feasible

• Magnetic– May disrupt electrochemical sensors

• Pending tests by Tufts

• Mechanical– No off-the-shelf impeller options– Custom impeller designed

18

Mixing Prototype Results

Results:• Too much slip with impeller to use

motor– Had to rotate impeller manually

• Sample developed air bubbles • Flour-like consistency very slow

settling time• Sediment remains on bottom of

chamber

Conclusions:• Fluid movement around sides easily

maintained• Need cross-bar near the bottom• Can maintain colloidal solution for

several minutes without continuous mixing with 10-micron grains

19

Sample Transport Prototype Results

Results:• ¾” tubing did not transport sample• 30% soil transported when dry• 95% soil transported when wet• Autoclaving did not affect soil

consistency

Conclusions:• 1” tubing• Water added to move sample

20

Autoclave Drawings

• 316 stainless steel• Height = 2 in. with flat

sides = 1.6 in. x 1.6 in.• Wall thickness = 0.125 in.• Inner Diameter = 1.5 in.

tapered

Bottom View

ValveInterface

Lid

Body

O-ring

SensorPorts

1” diameter

21

Reaction Chamber Drawing

Reaction Chamber with Mixer and Cap

• Ultem 1000• Height = 5.2 in. (13.19 cm)• Diameter = 1.6 in. (3.95 cm)• Wall thickness = 0.197 in. (0.5

cm)• Soil transport pathway = 1.0 in.

(2.5 cm)• Cap to support mixing shaft• 20 sensor ports

– 12 electrochemical sensors– 7 multi use ports– 1 temperature sensor

Motor

Impeller

Cap

Sensor ports

22

Autoclave Stress Analysis

• Autoclave technique: – 121 C with steam to aid heat flow– 15 psi above atmosphere for saturated steam at 121 C

• Thin wall pressure formulas:– Minimum thickness = 0.011 in. while actual used = 0.125 in. – Critical pressure for 0.125 in. is 20 kpsi

• Seals:– Regular threads alone will not seal– O-ring compression seals made of silicone for high temperature and

pressure

• Conclusions:– O-ring seals are effective– Temperature of chamber is regulated and heater has limited heating

power– Pressure relief valve added to 10-32 port on lid

23

Electrical System

• Power supply is 12V• Power conditioning is added to give cleaner power• 5V power will be used to run sensors because of

voltage stability

5 Amps

Circuit Breaker

On off Switch

SW-SPST

100uF

C?Cap

D?D Zener

GND

+12VDC +5VDC

IN3

OUT2

11

U?LM340-XX

.22uF

C?Cap

.1uF

C?Cap

GND

+12VGNDEarth

Power Supply

Power supply AC-DC converter Voltage regulator

24

Sensors and Control

• Sensors will run constantly

• Switchboard controls power to:– TECs, mixers and

LEDs

• The DAQ card can proportionally control:– Pumps, TECs and

mixers

Power Supply Power Distribution

Switch Board

Sensors

Computer

Analog Input

Digital input

Analog Output

Autoclave Heater1 LED's Autoclave heater2

Autolcave TEC 1Autoclave TEC 2

RC Control 1RC Control 2

Mixer Control 1Mixer Control 2

3x 3x 3x 3x 3x 3x

6x2x2x 2x

10x20x

6x

18x

2x

9x

Mixer 2 Mixer 1 RC TEC 2 RC TEC 1 AC TEC 2 AC TEC 1

2x2x2x2x2x2x

25

Software TimelineStart

0

Inse

rt s

ampl

e

30 s

Autoclave A

Turn on

Autoclave control1. User turns on program

2. Autoclave A begins heating

3. At 121˚C Autoclave A holds for 15 min

4. Autoclave A begins cooling and Autoclave B begins heating

5. Autoclave A finishes cooling

6. Autoclave B finishes cooling

7. Program notifies user autoclave has completed

1.5 hr

Autoclave B

Heating complete

27 hr

Done

2 weeks+ 27 to 75 hr

Finish

Done

Water pump A & B

Turn Valve

Reaction Chamber

Pumping complete

Reaction control1. User turns valves open

and beings program

2. Turn on pumps for 25 sec (at 1mL/sec flow rate)

3. Turn on Reaction Chamber control

26

Assembly Flow DiagramChassis

Autoclave chambers

(x2)

ReactionChamber

Envir.

Reagent H2O

Chamber

Reaction chamber

(x2)

Body Assembly

Body Assembly

TEC Assembly

Mixer Assembly

Body Assembly

DAQ

Embedded CPU

Interface

Temp. & pressure Sensors

ISE Package

Power supply

Power Supply

Body Assembly

Cap Assembly

TEC Assembly

Body

Pressure Seal

Insulation

Cap

Temp & Pressure Sensors

TEC

Heat SinkBody

Strip Heater

ISE Package

Motor

Bearing

Gears

Impeller

Body

Insulation

Temp & Pressure Sensors

TEC

Heat Sink

Body

Insulation

Strip Heater

Temp & Pressure Sensors

Power Supply

Interface

Sensors

Temp & Pressure

ISE Package

Thermal Control

TECs

Strip Heater

DAQ

Peristaltic Pump

Make

Buy

27

Functional Test Plan

Autoclave

ReactionChamber

TEC

Strip Heater

ThermalControl

ThermalControl

TEC

SampleTransport

MixingMotor

Butterfly Valve

SampleConsistency

Heat from -10°C to 121°CHold for 15 minCool to 20°C

Repeat 3 times

Transport 90% of samplewhen reagent water

pumped through

Impeller

Maintain temperaturebetween 4°C and 37°C

Maintain fluid movementaround sides; Maintain

minimal sedimentation onsides and bottom of chamber

DAQ &Control

Collection& Storage

Command

Interface

Software

Collect & store data fromeach sensor

Receive commands from SWProvide caution, warning,

status signals

28

Verification and Test Plan

ReactionChambers

Autoclaves

Reagent H2OChamber

SampleTransport

Temperature

Pressure

Mixing

Temperature

Pressure

Containment

Delivery

Sterilized sample

Inoculation

4°C – 37°C

1 psi differential

Small sedimentation, fluid flow @ sensors

Thermistor in environmental chamber

Pressure sensor in environmental chamber

Visual/Video verification

≥121°C

≥15 psi

Thermistor inside autoclave chamber through cap

Pressure sensor inside autoclave chamber through cap

Solid & liquid form

≤50mL (±5% accuracy)

Thermistor inside autoclave chamber through cap

< 60°C

Time-based flow rate in peristaltic pump (controlled flow)

Thermistor inside water chamber

Aseptic delivery Sterile swabbing of wet surfaces, culture test

Data Acquisition& Control

Collection & Storage

Caution, Warning,Status

Collected & stored forentire experiment

Provide status, caution & warning signals

DAQ storage capability analysis

Testing LabView command software with set max temperature and shut-off abilities

Power

NominalConsumption

PeakConsumption

≤ 30W

≤ 30W for ≤ 30 sec

Power model for all parts, measurement through multimeter in circuit

Petri dish testing with bacteria and medium (BioServe)Sample sterility No microbial life in sample

29

Risk Assessment

Probability

Sev

erity

Low

Low

Med

ium

Hig

h

Medium High

•Sample transport

•Autoclave

•Mixing

•Water transport

•DAQ

•Reaction Chamber Thermal Control

•Budget

•Machining Time

30

Work Breakdown Structure

MiDAs

Project Management Fabrication Verification and Testing

Systems Engineer

Shayla Stewart

Design Document

Project ManagerElizabeth Newton

Assistant Project Manager

Ted Schumacher

Lead Fabrication Engineer

Dave Miller

Assistant Fabrication

EngineerSameera

Wijesinghe

Design EngineerChuck Vaughan

Design Engineer

Jeff Childers

Software EngineerSteven To

Assistance as Needed from

Team

Assistance as Needed from

Team

Assistance as Needed from

Team

31

Schedule

32

Overall Budget  ITEM PART NUMBER QUANTITY PRICE ($)

THERMAL CONTROL        

 

Insulation (Melamine) 86145K27 1 (24"x48"x2") $ 49.48

Strip Heater HK5544R33.1L12B 7 $ 236.95

Thermoelectric Cooler (TEC) CP-0.8-127-06L 4 $ 106.40

Heat Sink HX6-201-L-M 4 $ 46.20

SENSORS  

 

Temperature SA1-RTD 6 $ 300.00

Pressure PX139 4 $ 340.00

ISE Package (18/pkg.)  - 2  $ 00.00 

MECHANICAL  

 

Ultem 1000 8686K81 1 (24”X2” rod) $ 155.00

316 Stainless steel 89325K673 2 (12”X2.5” rod) $ 300.00

Aluminum 89015K53 2 (48”X48”X0.0625”) $ 230.00

Bearing 6384K44 1 $ 7.41

Rotary-Shaft 1/4" Ring Seal 9562K41 1 $ 3.15

Pumps P625/275.133 2 $ 690.00

Motors 1224 2 $ 600.00

Butterfly Valve 4820K31 2 $ 173.27

COMPUTER/DAQ  

 

DAQ DMM-37X-AX 2 $ 480.00

Embeded CPU MOPSlcdLX 1 $ 450.00

Mixer Controller PA75CC 2 $ 25.00

Thermoelectric Controller WTC3243 4 $ 348.00

    TOTAL $4540.86

33

Resources and Facilities

• BioServe Laboratories– Matching funds– Spare/small parts– Machine shop– Temperature-controlled testing environment– Wet/Biological lab– Clean room

• Aerospace Department– Machine Shop– Electronics Shop

34

Conclusions

• Project feasible

• Team has necessary expertise, time and resources

• Risk mitigated through prototyping

• Can increase overall TRL

35

References1. Cengel, Yunus. Introduction to Thermodynamics and Heat Transfer.

McGraw-Hill. University of Nevada, Reno. 1997

2. Gilmore, David. Spacecraft Thermal Control Handbook. Aerospace press. El Segundo, California. 2002

3. Mankins, John C. “Technology Readiness Levels.” April 6, 1995. http://ipao.larc.nasa.gov/Toolkit/TRL.pdf.

4. www.dimondsystems.com

5. www.kontron.com

6. www.matweb.com

7. www.mcmaster.com

8. www.melcor.com

9. www.minco.com

10.www.omega.com

11.www.sonaer.com

36

Presentation Appendix1. Title Page2. Briefing Overview3. Objectives4. TRL Objective5. Deliverables6. Requirements Overview7. Requirement Refinement8. Mars/Earth Comparison9. System Architecture (External)10.System Architecture (Internal)11.Mass Analysis12.Experiment Timeline13.Electrical Overview14.Autoclave Prototype15.Prototype Thermal Analysis16.Autoclave Prototype Results17.Mixing Prototype18.Mixing Prototype Results

19. Sample Transport Prototype Results20. Autoclave Drawings21. Reaction Chamber Drawings22. Autoclave Stress Analysis23. Electrical System24. Sensors and Control25. Software Timeline26. Assembly Flow Diagram27. Functional Test Plan28. Verification and Test Plan29. Risk Assessment30. Work Breakdown Structure31. Schedule32. Overall Budget33. Resources and Facilities34. Conclusions35. References

37

Drawing Tree

38

Drawing Tree (continued)

Mechanical Drawing Tree

40

Autoclave Body

41

Autoclave Cap

42

Autoclave Bottom

43

Thermoelectric Cooler (TEC)

44

Heat Sink

45

Reaction Chamber

46

Reaction Chamber Cap

47

DC Motor

48

Impeller

49

Reaction Chamber Environment

50

Reaction Chamber EnvironmentSide Door

51

Peristaltic Pump

52

Pump Mount

53

PharMed Tubing

54

DAq

55

Embedded CPU

56

Chassis

57

Chassis Top

58

Chassis Front Interface

59

Electrical Schematic Tree

60

Electrical SchematicPower Supply Power Distribution

Switch Board

Sensors

Computer

Analog Input

Digital input

Analog Output

Autoclave Heater1 LED's Autoclave heater2

Autolcave TEC 1Autoclave TEC 2

RC Control 1RC Control 2

Mixer Control 1Mixer Control 2

3x 3x 3x 3x 3x 3x

4x2x2x 2x

10x20x

3x

20x

2x

9x

Mixer 2 Mixer 1 RC TEC 2 RC TEC 1 AC TEC 2 AC TEC 1

2x2x2x2x2x2x

61

Power System

5 Amps

Circuit Breaker

On off Switch

SW-SPST

100uF

C?Cap

D?D Zener

GND

+12VDC +5VDC

IN3

OUT2

11

U?LM340-XX

.22uF

C?Cap

.1uF

C?Cap

GND

+12VGNDEarth

Power Supply

62

Sensor Schematics

R

Sig+ VS

AP1

PX139

R

Sig+ VS

AP2

PX139

R

Sig+ VS

AP

PX139

R

Sig+ VS

RP

PX139

1K

AT1

Res3

1K

RT

Res3

1K

AT2

Res3

1K

TT

Res3

1K

CT

Res3

1K

AT

Res3

+5VDC

Sensor Diagram

GND

10K

R1

10K

R2

10K

R3

10K

R4

10K

R5

10K

R6

GND

GND

GND

GND

GND

123456789

101112

DAQ

63

Sensor Wire Harness+5VGNDSig

AP

+5VGNDSig

AP1

+5VGNDSig

AP2

+5VGNDSig

RT

+5VGNDSig

TT

+5VGNDSig

CT

+5VGNDSig

AT

+5VGNDSig

AT1

+5VGNDSig

AT2

+5VGNDSig

RP

SigGND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5VSig

GND+5V

DAQ Input

64

Control Schematics

MB?Pump Motor

MB?Mixer1

-V(ref)1SCI 2

+V(ref) 3PG 4

CLR

PG 5DC PI 6

- MI 7+ MI 8

Peristaltic Pump

P625

OAA- IAA

+ IAA- Vs

+ IAB+ VsOAB

Motor Control

PA75CC

1K

RI

Res31K

RF

Res3

CL

R

1 2 3

14 13 12 11 109 8

4 5 6 7

TEC CONTROLLERWTC3243

33.3K

RI

4.9KRP

1.5K

5K

1.5K

5K

+5VDC

20K

RBIAS

10K

Thermistor

10K

33.3K

RI

Control System

GND

GND

GND

MB?Mixer1

OAA- IAA

+ IAA- Vs

+ IAB+ VsOAB

Motor Control

PA75CC

1K

RI

Res31K

RF

Res3

GND

GND

GND

+12VDC

IHC2

CL

R

1 2 3

14 13 12 11 109 8

4 5 6 7

TEC CONTROLLERWTC3243

33.3K

RI

4.9KRP

1.5K

5K

1.5K

5K

20K

RBIAS

10K

Thermistor

10K

33.3K

RI

GND

IHC1

GND

10K

GND

RH1 RH2

GND GND

LED1 LED2

123456789

Computer

65

Control Schematics continued

CL

R

1 2 3

14 13 12 11 109 8

4 5 6 7

TEC CONTROLLERWTC3243

33.3K

RI

4.9KRP

1.5K

5K

1.5K

5K

20K

RBIAS

10K

Thermistor

GND

IHC2

CL

R

1 2 3

14 13 12 11 109 8

4 5 6 7

TEC CONTROLLERWTC3243

33.3K

RI

4.9KRP

1.5K

5K

1.5K

5K

20K

RBIAS

10K

Thermistor

GND

IHC2

MB?Pump Motor

-V(ref)1SCI 2

+V(ref) 3PG 4

CLR

PG 5DC PI 6

- MI 7+ MI 8

Peristaltic Pump

P625 Control System

GND

10K

123456789

Computer

GND

+12VDC

66

Control Wire Harness+12VGNDSig

Mixer1

+12VGNDSig

Mixer2

+12VGND+5V

TEC1

+12VGND+5V

TEC2

+12VGNDSig

TEC3

+12VGNDSig

TEC4

+12VGNDSig

Pump

+12VGND

Heater1

+12VGND

Heater2

GND+12VGND

+12VSig

GND+12V

SigGND

+12VSig

GND+12V

+5VGND

+12V+5V

GND+12V

SigGND

+12VSig

GND+12V

Control inputs

SigGND

+12V

+12VGNDSig

Pump

67

Switch board

SigSigSigSigSigSigSigSigSig

Digital Output

+12V+5V

GND

Power Distribution

+12VGND+12VGND+12VGND+12VGND+12VGND+12VGND+12VGND+12V+5VGND+12V+5VGND

Switched Items

1 23 45 67 89 1011 1213 1415 1617 18

2022242628303234

35 3637 3839 40

Switch Board

68

DAq Block Diagram

www.Dimondsystems.com

69

Embedded CPU

www.kontron.com

70

Software tree

AIn = Analog Input: Acquires pressure and temperature dataDBit Out = Digital Bit Out: toggles output high or low to control the switch boardErr Msg = Error message: displays error message if output is not configured rightTo Eng = Converts binary inputs from levels to voltage levelToEngArray= Converts array of binary inputs to voltage level

= Autoclave temperature/pressure.vi

= Elapse Timer: Counts amount of time elapsed after specific case

= Time Delay: Waits specified time before taking next sensor data

= Write File: Writes data to measurement file

71

Software Prototype