To design and build a portable easy-to-deploy system that can launch a weather balloon (up to ~10km) remotely via GSM in order to obtain atmospheric data via live radio transmission at a chosen location

1. GDP 15: Compact Remote High Altitude
Balloon Launcher
Group Design Project Final Presentation
Christian Balcer
Reetam Singh
Rahul Kharbanda
Sabin Kuncheria Purackal
Binay Limbu
Sullivan Pal

2. Introduction
 Aim:
 To design and build a portable easy-to-deploy system that
can launch a weather balloon (up to ~10km) remotely via
GSM in order to obtain atmospheric data via live radio
transmission at a chosen location

3. Key Systems Designed and
Manufactured
 Box
 Lid opening mechanism
 Gas release system (including gas
supply, delivery and balloon sealing)
 Balloon release mechanism
 Box electrical system
 Payload
 Payload electrical system
 Communications
 Key challenge: <67g

4. Further Tasks Involved
 Wind tunnel test
 CFD analysis
 FEA and FMEA
 Outreach program
 Field tests

5. Final Product Demonstration
 Successful fully automated launch tracked to 7675m
(25,180 ft)
 Video

6. Key box requirements
 Launcher Box
 Portable and compact
 Waterproof
 Minimal setup
 Endurance of 2 weeks
 High level of reliability

7. Box concept design
Concept design -1 Concept design -2
Concept design -3

8. Box material
 Materials considered
o Acrylic
o Foam sheet
o Metal sheet
 Biplex fluted polypropylene sheet ( Final box
material )
Image of biplex fluted polypropylene sheet

9. Box opening mechanism
Concept design-1 Concept design-2
Curved lever for the final design

10. Curved lever deflection
analysis
Deflection analysis by FEA - 5.63×10-3 m
Deflection analysis using Roark’s
formula for stress and strain-
Displacement plot of the
curved lever

11. Torque calculation
Angle (degree) Weight of box lid (N) Moment due to lid (Nm) Max torque required
(Nm)
Torque in kg.cm
0 2.9430 0.6769 1.5368 15.6671
10 2.8983 0.6565 1.5164 15.4582
20 2.7657 0.5978 1.4577 14.8597
30 2.5491 0.5078 1.3678 13.9426
40 2.2551 0.3975 1.2574 12.8175
50 1.8927 0.2800 1.1399 11.6200
60 1.4729 0.1695 1.0295 10.4942
70 1.0083 0.0795 0.9394 9.5760
80 0.5131 0.0206 0.8805 8.9758
90 0.0016 0.0000 0.8600 8.7661

12. Curved lever construction
Image of the constructed curved lever
• The jigsaw machine was used to cut the recycled
polypropylene (PP) sheet.
• A double cut flat file was used to file the work piece to
achieve the curved lever shape.
• Precision cutter like the laser cutters was avoided due
to budget constrains.

13. Box construction
Images of the constructed launch boxes
Gusseted plastic angle bracket used to attach
the box edges

14. Opening mechanism
test/issues
 Calculated required torque - 20 kg.cm
 Torque of servo used - 24 kg.cm
 Test -1 ( opening mechanism)
o Required required was high than calculated
o Possible solution- Use 2 servo, change gear ratio

15. Final design solution
 Changing the gear ratio gives twice the output torque
 This can also be done by attaching a lever
Free-body diagram of the force acting on the lever and canister

16. Final box design

17. Gas Supply
 Cylinder sizing: 2.2L @ 100 Bar
 Mass of He: 0.03676kg
 Volume of He at ground: 0.217m3
 Ascent rate 2.91m/s for payload of 67g
 Burst altitude: ~17.5km

18. Gas system schematic

19. Release Mechanism
 Balloon ‘always sealed’ using one-way valve
 Nichrome hot-wire: 32SWG gauge
 Approx 3.53A current heats up to 1000 degC
One-way valve
O-Ring
Packing
tape
Bottle lid
‘adaptor’ Superglue
Nichrome wire

20. Electronics
 Objectives:
 Provide support for all subsystems, including the payload
 Present a decent and predictable outdoor endurance on
standby
 Respond to a text message within a reasonable delay

21. Electronics
 Responses to those objectives:
 Use a magnetic reed to activate the payload once it
leaves the box, an Arduino micro-controller for all I/O
 Make a design of an external trigger
 Using the GSM shield, due to the ease of implementation

22. Electronics
 Outcomes/Learning outcomes:
 Arduino provided large flexibility that enabled us to test
time-efficiently that all subsystems were functional
 How to deal with multiple power sources
 Reliability

23. PAYLOAD
OBJECTIVES
• Measure the atmospheric parameters such as
temperature, pressure and humidity.
• Measure the altitude and give the location of the weather
balloon using GPS.
• Should be extremely light to conform to the low lift
generated by the small weather balloon used in the box.
• Should transmit under the unlicensed frequency band for
telemetry as this reduces the legal hassles involved.
• Keep records of the data collected by the payload for
data analysis

24. BINARY MATRIX

25. COMPLETE SOLUTIONS
EAGLE FLIGHT
COMPUTER
VAISALA RADIOSONDE

26. ONBOARD SYSTEM
• Arduino (MEGA/UNO/PRO MINI)
• 54 pins/22 PINS/20 PINS
• Operating Voltage : 7V-12V
• Supply voltage: 5V-3.3 V
• Flash Memory: 256 KB/32 KB/ 16 KB
• Easily Programmable and source code available for sensors compared
to other micro-computers.
• Power using 9V battery under sleep mode configuration.
• Thermal protection and casing using 5mm EPP Foam

27. SENSORSBAROMETRIC
PRESSURE/TEMPERATURE/
ALTITUDE
• BMP085
• Operating range: -40*C to
+85*C; accuracy +-2*C
• Operating height: 9km
HUMDITY AND
TEMPERATURE
SENSOR
• DHT22
• 0%-100% humidity
range with 2.5 %
Accuracy
• -40*C to 80 *C
temperature range

28. FINAL PAYLOAD

29. FINAL PAYLOAD

30. COMMUNICATION AND
TRACKING
FUNCTIONS OF TRACKING AND
COMMUNICATION
TRACKING:
KEEPING TRACK OF THE BALLOON
LOCATION i.e. LATITUDE , LONGITUDE
AND ALTITUDE
COMMUNICATION:
TRANSMITTING THE DATA OBTAINED
BY ONBOARD INSTRUMENTATION TO
GROUND RECIEVER FOR DECODING

31. TRACKING
DEVICE USED: ADAFRUIT GPS ULTIMATE
BREAKOUT
PROPERTIES:
1. TRACK UPTO 22
SATELLITES ON 66
CHANNELS
2. IN BUILT ANTENNA
3. 10 LOCATION UPDATES A
SECOND FOR HIGH SPEED
SENSITIVITY LOGGING OR
TRACKING.
4. EXCEPTIONALLY LIGHT 8.5g
5. FUNCTIONALITY UPTO 27
KM IN ALTITUDE

32. COMMUNICATION
DEVICE USED: RADIOMETRIX NTX2B
RADIO TRANSMITTER
PROPERTIES:
1. PERFECT FOR LICENCE-EXEMPT
OPERATION
2. OPERATING VOLTAGE OF 2.9V –
15V AT 18MA
3. DATA BIT RATE OF 10 KBPS
4. EXTREMELY LIGHT 5GM

33. MICROCONTROLLER
DEVICE USED: ARDUINO PRO MINI 5V (16 MHZ
MODEL)
PROPERTIES:
1. 22 PINS (14 DIGITAL, 8 ANALOG)
2. OPERATING VOLTAGE: 5V
3. SUPPLY VOLTAGE: 5 – 12V
4. FLASH MEMORY 16 KB
5. EXTREMELY LIGHT AND SMALL (2GM)

34. OPERATION
1. UPPLOAD THE MAIN PAYLOAD PROGRAM
WRITTEN IN THE ARDUINO IDE INTO THE ARDUINO
PRO MINI
2. THE PROGRAM EXTRACTS THE COORDINATES
AND ALTITUDE DATA FROM THE GPS AND SAVES
THEM INTO VARIABLES
3. PROGRAM EXTRACTS THE SENSOR READING
OBTAINED BY THE SENORS AND STORES THEM IN
VARIABLES
4. PROGRAM OBTAINED THEM PUTS THE OBTAINED
VALUES INTO A DATA STRING
5. THE DATA STRING IS PASSED TO A FUNCTION
WHICH DRIVES THE RADIOMETRIX NTX2B

35. DECODING
DEVICES NEEDED: DL FLDIGI SOFTWARE, RADIO
RECIEVERS OR ANDROID DEVICES RUNNING THE HAB
TRACKER SOFTWARE
1. THE RADIO RECIEVERS RECIEVES THE
RADIO SIGNAL TRANSMITTED BY THE
NTX2B
2. THE RADIO RECIEVER IS CONNECTED
TO A COMPUTER RUNNING DL FLDIGI
SOFTWARE WHICH DECODES THE
AUDIO SIGNAL INTO DATA
3. THE DECODED DATA IS UPLOADED
INTO THE SERVER RUNNING HABITAT
4. THE LOCATION OF THE BALLOON IS
PUT UP ON THE SPACENEAR.US MAP
5. VITAL TELEMETRY STATS ARE SAVED
IN THE SERVER RUNNING HABITAT.

36. CONSTRUCTION
1. PUT ALL THE INSTRUMENTS ON THE STRIP
BOARD
2. SOLDERED BY THE STUDENTS
THEMSELVES
3. ANTENNA’S ADDED TO IMPROVE THE
PERFORMANCE AND FUNCTIONALITY OF
THE RADIOTRANSMITTER

37. CONCLUSION
1.OBJECTIVE TO ACHIEVE A LIGHT
PAYLOAD THAT WOULD BE ABLE TO
FUNCTION AS A RADIOSONDE
2. FINAL PAYLOAD WEIGHT 59 GMS.
3. SENSITIVE INSTRUMENTS ONBOARD
TO MEASURE THE ATMOSPHERIC
PARAMETERS
4. LIVE DATA TRANSMISSION ON THE 434
MHZ FREQENCY BAND ENABLED
TRACKING AND MEASUREMENT
READINGS..

38. WIND TUNNEL TESTING

39. SETUP
 Conducted in 7’ x 5’
high-speed wind tunnel
 Box mounted upside-
down
 Connected to overhead
balance via struts
 Fixed to struts using
nuts and bolts

40. KEY RESULTS
 Wind sensor testing
 Video

41. 0
1
2
3
4
5
6
7
2 3 4 5 6 7 8
Drag(N)
Wind Speed (m/s)
Drag vs Speed at different opening angles
Lid at 225 deg from close
Lid at 180 deg from close
Lid at 135 deg from close
Lid at 90 deg from close
Lid at 45 deg from close
• Drag forces increase gradually with speed
• Maximum drag experienced when lid is perpendicular
• Result of increased planform area

42. 0
0.5
1
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6
Drag(N)
Wind Speed (m/s)
Drag vs Speed for box with the balloon (at
225 deg)
• Oscillating constantly, transferring load to ground
• On average, behaved linearly

43. ASSUMPTIONS
 Box was mounted upside down, optimally should have
been on the floor
 Very small gap between roof and box to prevent load
transfers
 Any lift produced was considered negligible
 Air was used to fill the balloon instead of helium via
inbuilt airline

44. FINAL DESIGN LAUNCH
PLANNING
 Appropriate sites selected
meeting launch
requirements
 ASTRA predictor used to
simulate balloon flight
pattern
 Liaised with members of
UKHAS who aided in
tracking
New Forest launch site
Winchester countryside launch site

45. LAUNCH 1
 Test was conducted in New Forest region
 High surface winds encountered on day
 Launch could not proceed due to failure of box opening
servo mechanism and leakage in gas delivery system
 Manual attempt resulted in balloon filling up with insufficient
helium to lift the payload
 Gas piping inspected and fixed to prevent leaks.
 More powerful servo obtained and replaced chains with
lever-wire system to increase torque

46. LAUNCH 2
 Partial success – reached altitude of 2400 m and retrieved
working payload
 Box opened successfully with lever mechanism
 Balloon successfully inflated with helium
 Balloon did not release automatically, shelf was nudged
slightly to release balloon
 Hole in the shelf was lubricated and increased in size to
allow valve to pass without obstruction
 Slight leak in balloon causing sudden descent after reaching
certain height

49. LAUNCH 3
 Test was conducted in an open field north of
Winchester (next to M3)
 Accomplished set objectives, fully remote launch
 Continuous sensor data relayed to multiple trackers
 Lost tracking at 7675 m altitude; payload could not be
retrieved

51. 0
20000
40000
60000
80000
100000
120000
0 2000 4000 6000 8000 10000
Pressure(Pa)
Altitude (m)
Pressure vs Altitude
-40
-30
-20
-10
0
10
20
30
0 1000 2000 3000 4000 5000 6000 7000 8000 9000
Temperature(°C)
Altitude (m)
Temperature vs Altitude
• As the balloon flew further
up, the ambient pressure
decreased
• Pressure went from approx.
100 kPa at sea level to a
minimum of 35 kPa at 7675
m
• With increasing altitude, the
surrounding temperature
reduced notably, going
below 0°C at approx. 3 km
• The initial temperature was
14.5°C and minimum
temperature was -32.09°C.

52. OUTREACH

53. OUTREACH

54. Objective completion

55. Conclusion
 Device demonstrated to a ‘proof of concept’ level
 Completed main objectives
 Further work possible to refine device
 Implementation of wind sensor
 ‘Industrialisation’ of internal component placement
 Launch success notification
 Demonstrate endurance and ‘weatherability’ of box
 Lighter payload for faster ascent rate
 Elegant interface for launching multiple boxes

56. Thank you for listening.
Please ask any questions.