High Altitude Adventures

High Altitude Adventures

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Jason Madigan

August 19, 2013
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Transcript

  1. 2.

    Background • Software Engineering type • Day Job • FeedHenry

    • Spare Time • Hacking (github.com/jasonmadigan) • iOS Apps • Irish Weather • Matchy • Bit of a Space nerd Monday 19 August 13
  2. 4.

    The Plan (1) Lifting Gas - Hydrogen €76 + Rental

    A cheap Android smartphone Parachute Weather Balloon Monday 19 August 13
  3. 6.

    The Plan (2) Lifting Gas - Helium €170 + Rental

    Arduino + GPS + Siemens TC35 + NTX2 Parachute Weather Balloon Monday 19 August 13
  4. 9.

    What’s in the box? Arduino Mega Siemens TC35 NTX2 MTK3339

    Veho Muvi HD (Not Pictured!) Monday 19 August 13
  5. 11.

    Arduino Mega • 4 Hardware Serial Ports • Software Serial

    ports introduce problems! • Processes GPS data from the MTK3339 • Processes incoming AT commands read from the GSM TC35 modem for sending/receiving SMS • Controls telemetry transmission via RTTY sent via NTX2 Monday 19 August 13
  6. 12.

    MTK3339 • Low power (20mW) • On-board data logging •

    Works above 18km • COCOM limits • 1900km/h && > 18000m - turn off • No intercontinental ballistic missiles, please • Actually worked up to 3.7km. Once. Monday 19 August 13
  7. 13.

    Radiometrix NTX2 • Low power transmitter UHF (10mW) • Free/unlicensed

    to use at low power in the UK & Ireland* • UKHAS use these since they’re easy to use • Used to transmit RTTY (Radioteletype) telemetry periodically * Table 5 - http://www.comreg.ie/_fileupload/publications/odtr0062r.pdf Monday 19 August 13
  8. 14.

    Xexun TK102 • Redundancy! • Cheap GPS Tracker with GSM

    (€30) • Terrible • Doesn’t work when it’s upside down • Randomly stops responding • Has failed to work on two HAB missions • I should probably throw it out. Remind me to throw it out. Monday 19 August 13
  9. 15.

    Veho Muvi HD • Full HD video capture (1080p) •

    Wide angle lens • Rugged, similar to a Go Pro, and a bit cheaper (€130) Monday 19 August 13
  10. 16.

    Siemens TC35 • GSM module with a serial (RS232) interface

    • Works with an Arduino • Low(ish) power 120mW while idle, can spike to ~700mW when sending/ receiving SMS Monday 19 August 13
  11. 17.

    How it all works • Redundant communications system • GSM

    (via TC35) • SMS processing - I can call or text “where”, and it will text me back its location • UHF (via NTX2) • Transmits periodic RTTY for decoding on the ground (dl-fldigi) • Cheap GPS tracker Monday 19 August 13
  12. 18.

    Bugs! • There were/are many • My favourite - Arduino

    serial interupts • Originally using an Uno • 1 hardware serial port (I needed 2) • Software serial ports • I have data, I interrupt • Oh you were transmitting? Sorry about that. Monday 19 August 13
  13. 19.

    Launching! • Legals • IAA - “No” • CAA -

    “Sure” • Picked a remote site with little tree cover an a wide-open space Monday 19 August 13
  14. 20.

    Launch Day • Oh crap the antenna broke • Oh

    crap the voltage sensor snapped off • Oh crap we forgot to put in the video camera • Oh crap I forgot to close the Helium valve before disconnecting the regulator Monday 19 August 13
  15. 23.

    Oops • Checked the predictor, started heading north towards Coleraine

    • “Odd, it’s altitude seems to be stuck at 3.7km” • GPS never regained a lock until it landed • We could hear the Payload via UHF Radio for the whole chase Monday 19 August 13
  16. 24.

    Silence • Shortly after regaining GSM coverage, the Radio went

    silent. • TC35 & GPS Tracker still working, so frantically called them • Eventually the main tracker told us its location Monday 19 August 13