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Team Tesla

Team Tesla . Anthony Thompson Philip de la Vergne Aaron Wascom Brandon Sciortino. Address concerns from previous PDR presentation Polarity Humidity Temperature Linear Actuator Breakdown Voltage at Sea Level Data Accuracy Data Frequency Requirements System Design Traceability

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Team Tesla

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  1. Team Tesla Anthony Thompson Philip de la Vergne Aaron Wascom Brandon Sciortino

  2. Address concerns from previous PDR presentation • Polarity • Humidity • Temperature • Linear Actuator • Breakdown Voltage at Sea Level • Data Accuracy • Data Frequency • Requirements • System Design • Traceability • Software • Principal of Operation • Payload Development • WBS Overview

  3. Polarity Acomparison of breakdown voltages for positive and negative corona

  4. Humidity Effect of absolute humidity on the breakdown voltage of a 30cm point-to-plane spark gap Parameter: Voltage Positive D.C Voltage A.C. Voltage

  5. Temperature Lower temperatures mean slower molecules, which means that the particles in the air collide with less kinetic energy. This drop in energy apprehends the production of ions and free electrons, which decrease the current created through the corona breakdown mechanism

  6. If the payload passes through a cloud the humidity will change rapidly making Its effect on the breakdown voltage more evident. The Smallest cloud () is about 1000 ft. tall so it insure we get a measurement inside the cloud we will measure no less than every 500 feet We ascend 1000 ft. per min and want to sample every 500 ft. so we will measure every 30 second's . • How accurate to our results need to be? • Temperature, Pressure, Humidity, Current, Voltage Data

  7. Data must be taken every 500 feet. A actuator will increase the distance across the spark gap to prevent a breakdown and the distance at that instant will be recorded. An analysis of the expected results of this method reveals that it is not plausible. The linear actuator would have to change the spark gap 19 mm every 500 ft. Assuming a constant voltage of 3000 V, the sea level pressure distance product on the x-axis of Paschen’s curve is 3 Torr-in. This requires a gap distance of 1.002 mm the gap distance would have to change by 19 micrometers every Linear Actuator

  8. The payload shall have a temperature sensor that can measure from 40 °C to -70° C and operate throughout the flight. • The payload shall measure Temperature to an accuracy of 1 degree Celsius • The payload shall measure Pressure to an accuracy of 1 Pa • The payload shall have a humidity sensor that can measure 0 to 100% relative humidity and operate throughout the flight. • The payload shall measure relative humidity to an accuracy of 1% • The payload shall have a pressure sensor that can measure 101.3 kPa to 1 kPaand operate throughout the flight. Technical Requirements

  9. Technical Requirements • The payload shall provide up to 4.5 kV in order to create a corona discharge at ground level • The electrodes shall have a point to plane configuration • The payload shall have a 1 mm spark gap • The electrodes shall be properly conditioned to provide a smooth finish • The anode shall be composed of a gold-plated copper point and the cathode shall be composed of copper • The payload shall weigh less than 500 grams. • The payload shall have two holes 17 cm apart for interfacing with the LaACESballoon. • Record and store data from flight so that it can be retrieved after flight for analysis • The payload will have enough power to operate throughout entire flight.

  10. Science Requirements • The electrodes shall be exposed to external temperature and humidity conditions • This payload shall consider a corona discharge of 10-5 Amps to be a breakdown • The payload shall increase the voltage with an accuracy of • The electrode configuration shall create a positive corona discharge • The onboard electronics shall be protected by a Faraday Cage around the spark gap • The payload shall record data every 500 feet to observe any clouds in the flight profile • The payload shall record temperature, pressure, humidity, and breakdown voltage from 0 to 100,000 feet

  11. System Design

  12. Measure pressure, temperature, humidity, breakdown voltage, and current across the spark gap Sensors: Piezoelectric, thermistor, relative humidity Exposed to environmental conditions Voltage across spark gap increased until 10 microamps are measured Voltage comparator observes corona discharge Switch opened, data recorded, voltage set to zero Principle of Operation

  13. Temperature Sensor • Select sensor that operates within requirements • Measure from -70 to 40 degrees Celsius • Operates within 40 degrees Celsius • Accurate to +/- 1 degree Celsius • Order Sensor • Draw preliminary schematic • Measure accuracy and compare to data sheet accuracy • Calibrate sensor according to difference between data sheet and observed accuracy • Determine necessary gain for op-amp conditioning circuit • Select resistors for op-amp circuit • Test to operate under 100% relative humidity • Test performance in thermal/pressure environments Electrical Development

  14. Electrical Development • Pressure sensor • Select sensor that operates within requirements • Measure from -70 to 40 degrees Celsius • Operates within 40 degrees Celsius • Accurate to +/- 133 Pa • Order Sensor • Draw preliminary schematic • Measure accuracy and compare to data sheet accuracy • Calibrate sensor according to difference between data sheet and observed accuracy • Determine necessary gain for op-amp conditioning circuit • Select resistors for op-amp circuit • Test to operate under 100% relative humidity • Test performance in thermal/pressure environments

  15. Electrical Development • Humidity sensor • Select sensor that operates within requirements • Measure from -70 to 40 degrees Celsius • Operates within 40 degrees Celsius • Accurate to +/- 1% • Order Sensor • Draw preliminary schematic • Measure accuracy and compare to data sheet accuracy • Calibrate sensor according to difference between data sheet and observed accuracy • Determine necessary gain for op-amp conditioning circuit • Select resistors for op-amp circuit • Test to operate under 100% relative humidity • Test performance in thermal/pressure environments

  16. Current Detection • Flight simulation • Compare to expected results to confirm system design • Draw Preliminary Schematic • Select resistor for voltage comparator circuit • Must allow for 10 microamps created at lowest voltage created • Select threshold voltage across resistor for voltage comparator • Select voltage comparator from threshold voltage, environmental requirements and 2ms response time • Operate from 40 to -70 degrees Celsius • Select JK Flipflop • Operate from -70 to 40 degrees C • 2ms response time • Determine high voltage at JK Flipflop for high at BASIC Stamp • Select transistor • Response time less than 2ms • Test transistor to confirm response time • Purchase materials for electrode configuration • Test to determine breakdown voltage at sea level • Finalize circuit schematics • Flight simulation • To confirm system design

  17. Mechanical Development • Determine required volume to contain components • Determine method of component attachment to payload • Determine required dimensions for interfacing and components • Thermal test to determine required thickness • Shock test • Add to weight budget

  18. Software Development • Read/Write to EEPROM • Determine syntax needed to input and output data to EEPROM • Develop subroutine to write data to EEPROM • Develop subroutine to prevent overwriting • Test to confirm coding • Reading sensors • Develop subroutines to • Record data from ADC • Read data from EEPROM • Timestamp data • Control Voltage • Develop subroutine to increase voltage • Test output voltage sent to DAC from BASIC Stamp • Ensure HVDC output voltage is the same value indicated by BASIC Stamp • Develop subroutine to record breakdown voltage • Develop subroutine to remove voltage across spark gap

  19. Mission Development • Full flight simulation prior to trip • Bring extra batteries, sensors, voltage comparator, JK flipflop, resistors, and HVDC • Assemble payload 24 hours prior to launch • Test operation off all components prior to launch • Launch • Run Pre-flight software that leads into operations software

  20. HVDC Development • Select and order HVDC based on electrode testing • Required breakdown voltage from materials testing • Draw Preliminary Schematic • Test and compare measured accuracy to data sheet • Calibrate HVDC according to difference between data sheet and tests • Determine required input voltages to create desired output voltages • Test performance in thermal/pressure environment • Draw finalized schematics • Flight simulation • Compare to expected results to confirm system design • Add all sensors to weight and power budget

  21. WBS

  22. WBS

  23. WBS

  24. Mission Goal Science Objectives Technical Objectives Science Background Science Requirements Technical Requirements System Design Power Budget Software Design Structural Design Management Overview

  25. To study the effects of humidity and temperature on the corona breakdown of the atmosphere in an effort to prevent sparking and ensure safety on future payloads. Mission Goal

  26. Observe the effect of temperature on corona breakdown voltage of the atmosphere • Observe the effect of humidity on corona breakdown voltage of the atmosphere Science Objectives

  27. Measure temperature of the atmosphere Measure pressure of the atmosphere Measure humidity of the atmosphere Measure the corona breakdown voltage as a function of pressure and gap distance Measure the current across the gap Meet all payload standards set by LaACES Technical Objectives

  28. Paschen’s Curve http://www.sciencedirect.com/science/article/pii/S146685640200067X

  29. Electron Avalanche

  30. Electrode Geometry & Polarity http://etd.auburn.edu/etd/bitstream/handle/10415/2044/Lipham_Mark_Thesis.pdf?sequence=1

  31. Humidity has an effect on the corona breakdown voltage by rearranging the polar water molecules entering the electric field. Effects of Humidity

  32. Temperature has an effect on the corona breakdown voltage through increasing the kinetic energy of the molecules within the spark gap. Effects of Temperature

  33. Electrode Material http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=13866&tag=1

  34. Electrode Roughness http://www.elect.mrt.ac.lk/HV_Chap1.pdf

  35. Environmental Conditions Team Philosohook’sResults

  36. The electrodes shall be exposed to external temperature and humidity conditions. • This payload shall successfully create a corona discharge. • The electrode configuration shall create a positive corona discharge. • The payload’s onboard electrons shall be protected with a Faraday cage. Science Requirements

  37. The payload shall have a temperature, pressure, and humidity sensor that can measure and operate throughout the flight. • The payload shall detect a corona discharge by intercepting a radio interference and detecting a current spike. • The payload shall have an HVDC Converter. • The electrodes shall have a point-to-plane configuration. • The electrodes shall be properly conditioned. • The anode shall be composed of a gold-plated copper point and the cathode shall be composed of copper. Technical Requirements

  38. High Level System Diagram

  39. SMHV Series sub-miniature regulated HV DC 0.434 cubic inch converter 0 to 10kV at 1 W of power 5VDC input On/Off Pin Voltage and Current monitor outputs Current Limiting Control inputs SHORT LEAD TIME HVDC Converter

  40. Current & Radio Wave Sensor Interface

  41. Power Budget

  42. Power Source AAA Energizer L92: Lithium vs. Alkaline http://data.energizer.com/PDFs/l92.pdf

  43. Flight Software Flowchart Temperature: 1 byte Humidity : 1 byte Pressure : 1 byte Time : 3 bytes Voltage : 2 byte Voltage Redundancy: 2 byte Current : 1 byte Current Redundancy :1 byte Radio : 1 bit Total : 97 bits

  44. Thermal Design

  45. External Structure 1.2cm 15cm 17cm

  46. Internal Structure

  47. Weight Budget

  48. Group Structure

  49. WBS

  50. Milestones

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