mission statement and objectives
DESCRIPTION
Mission Statement and Objectives. Design Requirements. Functional Log radiation and corresponding altitude for duration of flight (up to 90,000 feet and back) Store data on non-volatile memory - PowerPoint PPT PresentationTRANSCRIPT
Mission Statement and Objectives
Design Requirements
Functional• Log radiation and corresponding altitude for duration of flight
(up to 90,000 feet and back)• Store data on non-volatile memory• Provide power for duration of flight plus one hour set up and
one hour for recovery (4 hours minimum)• Indicate the unit is powered on• Indicate system is running properly • Ensure system is both water-resistant and buoyant• Provide internal fire resistance • Provide internal temperature regulation• Ensure system will operate within temperature range and
withstand forces of launch, ascent, balloon breaking, descent, and landing
• Ensure system can attach to research computer payload• Ensure combined system can attach to Borealis balloon Performance • Log radiation and altitude data each second • Provide 5 watts per hour over 4 hour flight• Provide sound and/or light to indicate power is on• Provide sound and/or light to indicate the system is operating
properly
• Ensure water cannot leak into system and payload floats• Enable system to shut down if internal temperature exceeds
100 C• Ensure system can withstand vertical force of 10Gs and
horizontal force of 5Gs (according to HASP requirements)• Ensure payload temperature stays within and will operate
between -60 and 60C (external) and between -20 and 40C (internal)
• Ensure pressure sensor can withstand 0-90kPa Physical• Ensure system does not exceed maximum dimensions: 5.5” by
5.5” by 5.5”• Ensure system does not exceed maximum mass: 6 lbs Reliability • Ensure system can launch twice and withstand internal tests:
• Drop test• Bench-top burn test• Cold room test• Water resistance test• Pressure test
• Recover all components and ensure internal components are not damaged
6
Choosing a PrototypeQuality/ Test Weight
Prototype 1 Prototype 2 Prototype 3 Prototype 4
Score Total Score Total Score Total Score Total
Temperature Gradient After 60 minutes
5 4 20 5 25 0 0 5 25
Burn Test 5 5 25 4 20 5 25 3 15Mass 5 4 20 5 25 3 15 5 25Temperature Loss After 60 minutes
5 5 25 2 10 4 20 5 25
Accelerometer 5 4 20 1 5 4 20 3 15Float Test 5 5 25 4 20 3 15 4 20
Total 135 Total 105 Total 95 Total 125
Picking Rigid Foam Board MaterialQuality/ Test Weight
Polyiso PolystyreneScore Total Score Total
Drill Test (with packing tape)
5 *5 25 2 10
Burn Test 5 5 25 5 25Mass 5 3 15 4 20
Temperature Gradient After 60 minutes
5 4 20 4 20
Temperature Loss After 60 minutes
5 4 20 5 25
Accelerometer 5 3 15 4 20Float Test 5 5 25 5 25 Total 145 Total 145
*Use Polyiso bottom to comply with attaching to other payload (better drilling score)
Final Prototype
-Hard Foam-Gorilla Tape
-Packing Tape
-Fiberglass
•Structural Material• Hard Foam
• Sides and Lid are polystyrene foam board• Bottom is made of polyiso foam board
Assembly•Method of Securing Electronics• ESD bag• Thinsulate bag• Packed in with shredded foam
•Method of Attaching Lid• Webbing with snaps
•Method of attaching to research computer payload• Bolts through our bottom into the top
of the other payload•Both payloads are then placed in a Nylon bag
CAD Video of Assembly
SpecificationsEnclosure Attachment Impact Forces/Environmental Protection
Specifications Pass? Specifications Pass? Specifications Pass?
6" cube check Attach to Research computer payload check Meets HASP requirements for G-
forces* check
Fits Electronics check Attach to BOREALIS check Buoyant &Water Resistant check
<1.0 kg check Electronics are secure check Lid is secure* check
Meets Internal Temperature Range* check
Electronics won't over heat * check
Testing
Tests to Check SpecificationsSpecifications Test
Meets HASP requirements for G-forces Accelerometer
Lid is secure Lid test with weight
Electronics won’t over heat Sun Test
Meets Internal Temperature Range Temperature Profile Test
Accelerometer Test Results•Three axis accelerometer with a lab view program• Converted voltages to G-Force
• ((V-2.7)/0.004)•Placed accelerometer inside the box (simulate what electronics feel)• Used a weight that had a mass of ~423 grams
• similar dimensions to electronics• Taped accelerometer to the weight
• Assembled as discussed above•Then placed the accelerometer on the outside of the box•Drop height of 3 meters
Accelerometer Test Results
17 1479 2941 4403 5865 7327 8789 10251117131317514637160990
100
200
300
400
500
600
700
800
900
Outside the Box
Sample Number
G-F
orce
12 1068 2124 3180 4236 5292 6348 7404 8460 9516 10572116280
50
100
150
200
250
300
Inside the Box
Sample Number
G-F
orce
•Max Resultant G-Force• ~788 G’s
•Max Resultant G-Force• ~276 G’s
Lid Test Results•Tied rope to bottom of box•Placed a weight inside• Used same weight as in accelerometer
test• Assembled as discussed before
•Swung box around in different directions•Had lid facing outward•Lid remained secure and didn’t move
Field Test Results•Calibrated thermocouples• Used: ice water, boiling water
•Used same heater as in cold tests• Assembled in manner described above
•Placed one thermocouple on the circuit board and one on the battery pack•Placed box in sun in 75⁰F weather • Measured temperature every 5 minutes• Stopped test when circuit board reached 60⁰C
• Test lasted75 minutes•Corrected the temperature readings using calibration curve•Graphed data (see next slide)
Thermocouple on circuit board
Thermocouple on battery pack
Field Test Results
0 10 20 30 40 50 60 70 800.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
Battery ThermocoupleCircuit Board Thermocouple
Time (min)
Corr
ecte
d Th
erm
ocou
ple
Tem
pera
ture
s (⁰C
)
•Assembled in manner described above•Placed one thermocouple on the circuit board and one on the battery pack•Placed in thermal oven• Took temperature measurements every 5 minutes• Followed the external temperature data from last years flight
•Corrected the temperature readings using calibration curve•Graphed data (see next slide)
Temperature Profile Test Results
Temperature Profile Test Results
0 20 40 60 80 100 120 140
-50.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
20.0
30.0
40.0
External Temperature
Battery Temperature
Circuit Board Temperature
Time (min)
Tem
pera
ture
(⁰C)
Mechanical Subsystem Bill of MaterialsBuilding Materials: $119.05packing tape, fiberglass kit,
gorilla tape, gorilla glue, nylon etc.
+Shredded Foam: $2.49+Polystyrene ½” Board: $2.45+Thinsulate: $14.99+TI Sensor Tag: $25
Total: $163.98
Schematic
Burn In Test
Burn In Test ResultsTime Voltage Battery Current Battery Voltage Converter Current Converter
5 min 8.900 0.1080 5.009 0.176
15 min 8.960 0.1080 5.009 0.175
30 min 8.990 0.1080 5.009 0.179
45 min 9.010 0.1086 5.009 0.177
60 min 9.015 0.1080 5.009 0.179
75 min 9.020 0.1073 5.009 0.180
90 min 9.022 0.1088 5.009 0.179
105 min 8.990 0.1087 5.009 0.176
120 min 9.000 0.1088 5.009 0.174
135 min 8.997 0.1087 5.009 0.180
150 min 8.960 0.1090 5.009 0.179
165 min 8.970 0.1094 5.009 0.175
180 min 8.974 0.1080 5.009 0.174
195 min 8.970 0.1090 5.009 0.177
210 min 8.971 0.1090 5.009 0.176
225 min 8.970 0.1077 5.009 0.175
240 min 8.970 0.1080 5.009 0.174
255 min 8.960 0.1090 5.009 0.177
270 min 8.966 0.1070 5.009 0.174
285 min 8.970 0.1084 5.009 0.175
300 min 8.970 0.1090 5.009 0.177
Static/ESD Bag Test
Due to the packaging method, static was a concern.
Using a oscilloscope the box was tested both with and without an ESD bag.
Conformal CoatingConformal coating was required due to both the geiger counter and the packing style of the payload.
Arathane (Uralane) 5750 Conformal Coating*Material Function Amount/10 Actual Amount
Uralane 5750 LV-A Curing Agent 0.54 g 0.84 g
Uralane 5750 LV-B Pre-polymer 3 g 4.47 g
Toluene (70 PBV) Diluent 2 g 2.96 g
* A similar product was used to stake the geiger counter
•Step 1: Cleaned boards• One bath Liquinox and DI water, followed by
two alcohol baths•Step 2: Dried boards• Placed in oven for approximately 45 minutes
•Step 3: Masked boards• All parts that could not be coated were
masked off•Step 4: Coating boards• Boards were coated with Arathane conformal
coating•Step 5: Dried boards• Boards were placed in oven for 14 hours at
50°C
Finished Payload
Geiger Counter: $149.95+Pressure Sensor: $45.44+DC/DC Converter: $19.97+Batteries: $69.70+Battery Packs: $4.98+PC Boards: $8.98+Thermal Cutoff: $8.91+USB Cables: $15.99+Misc: $2.80
Total: $326.72
Budget
0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100
104
108
112
116
120
124
128
132
136
140
144
148
0
100
200
300
400
500
600
-50
-40
-30
-20
-10
0
10
20
30
Radiation, Pressure, and External Temp vs Time
Radiation Counts (cpm)Pressure (psi)External Temp (⁰C)
Time (minutes)
Radi
ation
Cou
nts
(cpm
)
Pres
sure
and
Ext
erna
l Tem
p
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 750
200
400
600
800
1000
1200
1400
1600
1800
0
2
4
6
8
10
12
14
Radiation and Pressure vs Time
Radiation Counts (cpm)Pressure (psi)
Time (minutes)
Radi
aito
n
Pres
sure
Budget
Raspberry Pi: $25+SD Card:
$13
Total:$38
Overall Budget
ME Materials $163.98+EE Materials $326.72+CS Materials $38.00
Total: $528.70
$71.30 under budget!!!
Thank You!