Download presentation - Senior Design

Wireless TPS Sensors
Chris Johnson
Jesse Pentzer
Brandy Holmes
John Sochacki
Lucus Wells
Outline
 Background
 Needs/Specs
 Designs
 Design 1
 Design 2
 Design 3
 Trade Study
 Sensors
 Budget
 Schedule
 Challenges
 Conclusion
 Acknowledgments
Slide #2
Background
Slide #3
 The re-entry environment is extremely
difficult to model.
 NASA Ames desires a wireless sensor
system that can be integrated into the
Thermal Protection System (TPS) of
entry vehicles.
 Complications with adding extra wiring
and the risk involved in adding sensors
to the mission.
 A wireless sensor system would remove
wiring complexities, reduce mass, and
reduce risk associated with cable cutting.
 With a greater understanding of the
environment encountered during
atmospheric re-entry the TPS of future
missions could be made safer and more
efficient.
Needs/Specifications
Need
Specification
Slide #4
Target Value
Unit
Multi-Nodal Wireless Architecture
1)
Number of Nodes Architecture can Support
10
Multiple Sensors per Node
2)
Number of Sensors per Node
5
Multiple Sensor Types per Node
3)
Minimum Number of Different Sensors Per Node
>= 2
Integration with Rise Balloon
4)
Maximum Size
4 x 5 x 0.5
inches
5)
Maximum Weight
16
ounces
6)
Sensor Pressure
0 to 14
psi
7)
Minimum Sensor Temperature
-60
°C
8)
Maximum Sensor Temperature
1000
°C
9)
Wireless Signal Range
10
meters
10)
A to D Resolution
10
bits
11)
Maximum Electronics Temperature
125
°C
X-Jet Testing
Design One
Sensor
Slide #5
Design #1 & #3
Wire
Sensor Node
Sensor
Node 1
Sensor
Wire
Thermocouples
Sensor
Signal Flow
RF Wireless Link
Wire
Sensor
Node 2
Sensor
Wire
RTD
Network
Analog
Analog
Pressure
Sensor
Wire
Cold
Junction
Correction
Chip
Amplification
UART
Receiver
Analog
PIC
Micro- UART Buffer
processor
UART
XBee
Wireless
I2C
Sensor
Receive
Node
RF Wireless Link
Wire
Wire
Sensor
Sensor
Node 3
Sensor
Wire
Wire
Sensor
RF Wireless Link
Power Flow
Sensor
Li Ion
7.4V
Battery
7.4V
Battery
Protection
Circuit
5V LDO
Regulator
5V
PIC Microprocessor
5V
RTD
Network
5V LDO
Regulator
5V
Buffer
5V
Pressure
Sensor
5V LDO
Regulator
5V
3.3V LDO
Regulator
3.3V
7.4V
Cold Junction
Correction
Chip
XBee
5V
Amplification
Design One
Slide #6
Design #1, #2, & #3
Receiving Node
Transmitter
Power Flow
Signal Flow
XBee
Pro
Reciever
Li Ion
7.4V
Battery
Battery
Protection
Circuitry
Rabbit Microprocessor
Data
Acquisition
3.3V LDO
Voltage
Regulator
XBee
3.3V LDO
Voltage
Regulator
Rabbit
Microprocessor
Design Two
Sensor
Slide #7
Design #1, #2, & #3
Wire
Receiving Node
Sensor
Node 1
Wire
Sensor
Wire
Sensor
Node 2
Sensor
Wire
Wire
Wire
Sensor
Sensor
Node 3
Sensor
Wire
Wire
Sensor
Rabbit Microprocessor
Data
Acquisition
Transmit
Node
Wire
Wire
XBee
Pro
Reciever
RF Wireless Link
Sensor
Sensor
Transmitter
Receive
Node
Signal Flow
Wire
Wire
Power Flow
Sensor
Li Ion
7.4V
Battery
Battery
Protection
Circuitry
3.3V LDO
Voltage
Regulator
XBee
3.3V LDO
Voltage
Regulator
Rabbit
Microprocessor
Design Two
Slide #8
Design #2 & #3
Design #2 & #3
Sensor Node
Transmit Node
Analog
Power Flow
Pressure
Sensor
Li Ion
7.4V
Battery
Cold Junction
Correction
Chip
Amplification
UART
Sensor Node
Transmit Node
Analog
PIC
Microprocessor
Signal Flow
RTD
Network
Analog
UART
Receiver
UART
UART
or I2C
UART
Rabbit Microcontroller
UART
I2C
7.4V
Battery
Protection
Circuit
7.4V
5V LDO
Regulator
5V
PIC Microprocessor
5V
RTD
Network
5V LDO
Regulator
5V
Buffer
5V
Pressure
Sensor
5V LDO
Regulator
5V
Cold Junction
Correction Chip
5V
Amplification
Power Flow
Signal Flow
Thermocouples
Li Ion
7.4V
Battery
7.4V
Battery
Protection
Circuit
7.4V
5V LDO
Regulator
5V
3.3V LDO
Regulator
3.3V
XBee
5V LDO
Regulator
5V
Rabbit Microcontroller
UART of I2C
XBee
Wireless
Design Three
Sensor
Slide #9
Design #1, #2, & #3
Wire
Receiving Node
Sensor
Node 1
Sensor
Wire
Wire
Receive
Node
Wire
Sensor
Node 2
Sensor
Wire
Wire
Data
Acquisition
RF Wireless Link
Transmit
Node
Wire
Wire
Wire
Sensor
Sensor
Power Flow
Sensor
Node 3
Sensor
Rabbit Microprocessor
RF Wireless Link
Sensor
Sensor
XBee
Pro
Reciever
Signal Flow
Sensor
Transmitter
Wire
Wire
Sensor
Node
Wire
Sensor
Sensor
Sensor
Li Ion
7.4V
Battery
Battery
Protection
Circuitry
3.3V LDO
Voltage
Regulator
XBee
3.3V LDO
Voltage
Regulator
Rabbit
Microprocessor
Design Three
Slide #10
Design #1 & #3
Design #2 & #3
Sensor Node
Analog
Power Flow
Pressure
Sensor
Li Ion
7.4V
Battery
Cold
Junction
Correction
Chip
Amplification
Thermocouples
UART
Analog
PIC
Micro- UART
processor
Buffer
UART
XBee
Wireless
7.4V
RTD
Network
Analog
Pressure
Sensor
I2C
Battery
Protection
Circuit
Analog
Cold Junction
Correction
Chip
UART
Amplification
Analog
Transmit Node
Receiver
Signal Flow
RTD
Network
Analog
5V LDO
Regulator
5V
PIC Microprocessor
5V
RTD
Network
5V LDO
Regulator
5V
Buffer
5V
Pressure
Sensor
7.4V
5V LDO
Regulator
5V
3.3V LDO
Regulator
3.3V
Cold Junction
Correction
Chip
XBee
5V
Amplification
Power Flow
Signal Flow
Thermocouples
Sensor Node
Li Ion
7.4V
Battery
PIC
Microprocessor
UART
I2C
7.4V
Battery
Protection
Circuit
7.4V
5V LDO
Regulator
5V
PIC Microprocessor
5V
RTD
Network
5V LDO
Regulator
5V
Buffer
5V
Pressure
Sensor
5V LDO
Regulator
5V
Cold Junction
Correction Chip
5V
Amplification
Design Three
Slide #11
Design #2 & #3
Transmit Node
Power Flow
Signal Flow
Sensor Node
Receiver
UART
Li Ion
7.4V
Battery
7.4V
Battery
Protection
Circuit
UART
or I2C
7.4V
UART
Rabbit Microcontroller
5V LDO
Regulator
5V
3.3V LDO
Regulator
3.3V
5V LDO
Regulator
5V
UART
UART of I2C
XBee
Rabbit Microcontroller
XBee
Wireless
Trade Study
Slide #12
Value of Designs (1-3)
Item
Design 1
Design 2
Design 3
Comments
Low Cost
1
3
2
all will meet budget
Small Size
3
1
2
node size minimized
Low Weight
3
1
2
low impact on VAST balloon
Low Software Complexity
2
3
1
Low Hardware Complexity
3
1
2
Low Power Consumption
1
3
2
Meets additional Priorities
2
3
1
priorities besides #1's
Low Packaging Complexity
3
2
1
protective packaging only
High Usability
2
1
3
includes versatility
Feasibility
3
2
1
Summation
23
20
17
This total would suggest that the completely
wireless option has the most benefits
Sensors

Omega Type K Thermocouples with Glass Braid Insulation
 Range: -270 to 1372 °C
 Uncertainty: Greater of 2.2 °C or 0.75%
 Cost: $33 for five thermocouples with one meter leads

Honeywell ASDX-DO Series Pressure Sensors





Range: 0 to 30 psi absolute
Uncertainty: 2.0% Full Scale
Temperature Range: -20 to 105 °C
Cost: $33.27 Each
Omega Thin Film Resistance Thermal Detectors
 Range: -70 to 500 °C
 Uncertainty: Dependent on Calibration Equation
 Cost: $47.50 for pack of five
Slide #13
Budget
•
•
Common Cost to all designs: $679.16
Design One
•
•
•
9 PCB’s
9 Batteries
9 X-Bee chips
•
•
Design Two
•
•
•
11 PCB’s
3 Batteries
3 X-Bee’s
•
•
Total Cost: $1137.41
Design Three
•
•
•
11 PCB’s
5 Batteries
5 X-Bee’s
•
•
Total Cost: $1333.91
Total Cost: $1222.91
Thermal Exposure’s Budget: $2240
Slide #14
Schedule
Slide #15
Challenges
Slide #16
 Code Complexity
 RF Opaque Materials
 Design Packaging for
Harsh Landing
Conditions
 Thermal Protection of
Circuit
Conclusions
 Thermal Exposure’s Favorite?
 Design One!!!
 Why?
 Versatility
 Simplicity of Code
 Simplicity of Design
 Small Size and Weight
Slide #17
Acknowledgments
 Faculty Advisors
David Atkinson
Steve Beyerlein
 Mentors
Greg Swanson
Tye Reid
Justin Schlee
 NASA Ames
David Hash
Johnny Fu
Ed Martinez
Slide #18
Slide #19
Questions?