Waterproofing Electronics Discussion

Discussion in 'Rocketry Electronics and Software' started by K'Tesh, Jun 8, 2019.

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  1. Jun 8, 2019 #1

    K'Tesh

    K'Tesh

    K'Tesh

    OpenRocket Chuck Norris

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    In thinking about Reed Timmer's recent success for getting an electronics sensor package into a tornado using a Quest Magnum Sport Loader (3012), I've been thinking about how I'd do it.... Tornadoes frequently are rain wrapped, and I'm thinking that to protect the sensor it could be inserted inside a large uninflated balloon (clear being the best color option). I feel that it shouldn't affect the electronics ability to do pressure sampling, but would greatly reduce the chance of water infiltration of the unit greatly increasing it's lifespan and preventing data loss.

    I also think that (at least in his case) a piece of foam could be glued inside the nosecone (for buoyancy), and a couple pieces could be wrapped around the electronics to prevent it from being damaged from being bashed about should the unit come down and snag on something while the wind is still strong.

    So, am I onto something? Would this work for us with our applications (say launching at BONG)? Or am I way off base here? I don't remember seeing any discussion on this topic directly.
     
    Last edited: Jun 8, 2019
  2. Jun 8, 2019 #2

    K'Tesh

    K'Tesh

    K'Tesh

    OpenRocket Chuck Norris

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    Another option could be to use a condom, but that's a lot thinner, and I'm thinking that it could be more easily damaged. Balloons can be bought in packages of 100 (or more), and a single color (and likely for far less than a supply of unlubricated condoms) . I know, I've bought several thousand balloons over the years in my street preforming days and a bag of 100 is typically less than $10 USD from a wholesaler.

    The only concern I can think of is the powder used to keep balloons from sticking to each other (and the insides to themselves).
     
  3. Jun 9, 2019 #3

    OverTheTop

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    Powder in the balloons will not affect the baro sensor. The membrane in them is impervious to neutral fluids in general, so a bit of powder will not have any effect. I could imagine some dampness mixing with the powder to create an ionic (ie conductive) residue that might cause issues on the PCB surface. It can be coated with conformal coating to keep this from becoming a problem. Just make sure the hole in the baro sensor, any switches or terminals or buzzers are masked before spraying :). Alternatively you can brush the coating on.
     
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  4. Jun 9, 2019 #4

    Motocrossman24

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    Why not conformal coat it? Then you don’t have to deal with the annoyance of pulling it out and putting back into a balloon, and don’t have to worry about it overheating in a balloon.
     
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  5. Jun 10, 2019 #5

    OverTheTop

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    Just conformal coating on its own would be a viable solution if done properly.

    Having said that, the components listed above (switches, buzzers, terminals) will not be coated and may experience corrosion from exposure to the atmosphere.

    I guess you could put it in a box with either a flexible membrane, or a gas permeable membrane , or even a balloon ;).
     
    Last edited: Jun 10, 2019
  6. Jun 10, 2019 #6

    blackjack2564

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    I have 2 rockets "Bong-a-fied" fiberglass with foamed NC's carved to hold Rf tracking.

    Straws taped to threaded rod for antenna along outside edge of cone, box carved into foam for tracker.

    It floats on surface of water just like a fishing bobber while rest of rocket remains semi-submerged like iceberg. Never would find water landing with out at the BONG...used many..many times. Signal just happily beeping away!

    To water proof av-bay..use sections of aquarium hose. Insert into proper sized vent holes and wrap into circles at least 2x. Now you have mini "P" traps..water will get into hose but cannot get into av-bay. How it's been done for many years.
    Heck most modern altimeters are conformal coated already and you can just dry out everything by placing on dash in sun.

    I have submerged far too many and all work fine after some rinsing will clean water and a dry out.

    Ya'll are overthinking a simple problem.

    100_2446.jpg 100_2449.jpg 100_2448.jpg
     
  7. Jun 10, 2019 #7

    K'Tesh

    K'Tesh

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    However, Tim's rockets are being launched into tornadoes... High winds, rain, and hail could all take its toll on his sensor packages.

    I'm confused by your description of the P Trap... Do you have any photos?

    Thanks!
     
  8. Jun 10, 2019 #8

    Andrew_ASC

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    At SEDS last year we pulled an APRA out of a literal chest deep swamp in Tampa Tripoli prefect. It beeped anyways after a new battery. Just saying.
     
  9. Jun 10, 2019 #9

    OverTheTop

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    That has not been my observation. All I have purchased have been bare PCAs.
     
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  10. Jun 10, 2019 #10

    timbucktoo

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    Aggreed. Ive drowned a MARSA & TeleGPS. Both recovered pretty quickly. Dried them in sun. Sent both back to manufacturers to see what they could do if anything and both were DOA. Did similar with perfect flight SL100. That was also sent back. Peter did coat it at that time and it did work, for a while.
     
  11. Jun 11, 2019 #11

    bobby_hamill

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    what about installing a valve that can be closed by timer or ejection charge ?
    the valve stays open to collect data and is closed by timer or at ejection charge

    Bobby
     
  12. Jun 11, 2019 #12

    OverTheTop

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    Might work for some applications, but for doing DAQ in tornados/hurricanes the sensor needs to be physically available to the nasty weather.
     
  13. Jun 11, 2019 #13

    cwbullet

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    I have one altimeter (RRC2) that spent 8 months in a tree. The AV compartment was filled with water but it survived. It continues to fly today.
     
  14. Jun 12, 2019 #14

    Sabrina

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    "Bong-a-fied" - yup - that's going in my new vocabulary list for sure! :D:cool::p:D

    I have heard about the "tracker in a foamed nosecone"... But that picture of yours - thanks! - Flashbulbs are going off in my head now thinking of all the possibilities!!! o_O:p:eek:o_O

    I like to visualize... Got any pictures of the "Mini P Trap"???
     
  15. Jun 12, 2019 #15

    MikeyDSlagle

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    Are the tubing circles/coils inside the AV bay or wrapped around the rocket. Copper line could be used for a more permanent and classy look.
    Interesting concept. I may try it just for the smell of it, we don't have water hazards. Well during the flooding a few years back we did, but that was an exception.
     

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