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