Revision to Tripoli Rule Regarding Wireless Remote Switches

Discussion in 'Rocketry Electronics and Software' started by Steve Shannon, Feb 4, 2020.

Help Support The Rocketry Forum by donating:

  1. Feb 14, 2020 #751

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter

    Joined:
    Feb 3, 2012
    Messages:
    3,412
    Likes Received:
    662
    I have also seen some of the cheap knock-offs (i.e. virtually all of the ones sold on eBay) that can be reversed without a whole lot of effort. I've also seen knock-offs with reversed wires, which is even worse, and with very loose connectors that can pop out or loosen when connected. I get a black Sharpie and mark the sides of black ("-") wires on both sides of the connectors... that way you just have to match the black stripes. And, push the wires inwards to make sure they're 100% seated, and tape the heck out of them so they can't come loose.
     
    Mike Helm and warnerr like this.
  2. Feb 14, 2020 #752

    g.pitts

    g.pitts

    g.pitts

    Forum Supporter TRF Supporter

    Joined:
    Aug 27, 2019
    Messages:
    200
    Likes Received:
    90
    Gender:
    Male
    Location:
    Beaverton, OR
    What could POSSIBLY go wrong with those issues? :eek:
     
  3. Feb 14, 2020 #753

    mpitfield

    mpitfield

    mpitfield

    Moderator Staff Member TRF Lifetime Supporter Global Mod

    Joined:
    Jul 7, 2013
    Messages:
    4,677
    Likes Received:
    318
    Gender:
    Male
    Location:
    Toronto, Ontario
    I purchased a batch from Ebay a few years back and there was at least one that had reversed wires. I think I soldered it to one of my Eggtimer products and you helped me troubleshoot it.
     
    g.pitts likes this.
  4. Feb 14, 2020 #754

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter

    Joined:
    Feb 3, 2012
    Messages:
    3,412
    Likes Received:
    662
    That's what I've been saying... recovery system safety is about all of the components, not just the altimeter or the switch. You need to look at every single piece and think about what could go wrong with it in flight. That's why I think there needs to be a certification for electronic deployments... if you're new to electronic deployments you need some guidelines so you'll be thinking safety from the get-go.
     
    g.pitts likes this.
  5. Feb 14, 2020 #755

    wsume99

    wsume99

    wsume99

    Well-Known Member

    Joined:
    Feb 28, 2014
    Messages:
    160
    Likes Received:
    39
    1000% agree. I'm building my first e-bay and I've spent waaaaay more time researching electronics, batteries, sled designs, connectors, wiring, switches, etc than I did researching building techniques when building my L1 rocket. IMO it's not that complicated but details certainly matter, at least to me they do. Every single component must work correctly to have a successful flight. It's a deployment system, not just an altimeter.
     
    wolsen and g.pitts like this.
  6. Feb 14, 2020 #756

    Kelly

    Kelly

    Kelly

    Usually remembers to get the pointy end up

    Joined:
    Apr 26, 2010
    Messages:
    110
    Likes Received:
    35
    Location:
    Oregon
    Yeah, I'm talking about cheap knock-offs, which seem to be the default. I've taken to plugging the two together correctly, then coloring the "top" side of both male and female with a sharpie. Then I just make sure the sharpie sides (or the non-sharpie side) match up when I connect. Either side can be "top", doesn't matter as long as they're connected properly when you mark.
     
  7. Feb 14, 2020 #757

    g.pitts

    g.pitts

    g.pitts

    Forum Supporter TRF Supporter

    Joined:
    Aug 27, 2019
    Messages:
    200
    Likes Received:
    90
    Gender:
    Male
    Location:
    Beaverton, OR
    You've got the right solution given the available product and quality level!
     
  8. Feb 14, 2020 #758

    heada

    heada

    heada

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    2,698
    Likes Received:
    206
    Gender:
    Male
    Location:
    Indianapolis, Indiana
    I think another cert level for electronics is a bad idea. It would complicate cross certification with NAR and unless you want to go to L3, electronics aren't required. I could see an endorsement on cert levels like L2 with staging or L1 with electronic deployment but I'm failing to see a benefit to those without restricting the base cert levels which is something I wouldn't want to do.

    There are many different solutions to the switch issue but adding more restrictions is not a good one in my eyes.
     
    Steve Shannon and Nytrunner like this.
  9. Feb 14, 2020 #759

    rharshberger

    rharshberger

    rharshberger

    Well-Known Member

    Joined:
    Oct 13, 2014
    Messages:
    8,690
    Likes Received:
    989
    Gender:
    Male
    Location:
    Pasco, WA
    Well said, and +1.
     
  10. Feb 14, 2020 #760

    g.pitts

    g.pitts

    g.pitts

    Forum Supporter TRF Supporter

    Joined:
    Aug 27, 2019
    Messages:
    200
    Likes Received:
    90
    Gender:
    Male
    Location:
    Beaverton, OR
    We could quibble about whether electronic deployment requires a separate certification or whether L1 and L2 SHOULD have more training in awareness in its use. There are L1 and L2 flights that are using electronic deployment today. I'd rather people have better awareness of what to do, and equally important what NOT to do when creating an electronics bay. Again, this could be training within a certification or outside of a certification. I don't care. I DO care about some of the work I've seen from people who can't solder well and have no idea about thinking ahead to failure mechanisms. People can and will get hurt from that.
     
    Speaknoevil and Steve Shannon like this.
  11. Feb 14, 2020 #761

    wsume99

    wsume99

    wsume99

    Well-Known Member

    Joined:
    Feb 28, 2014
    Messages:
    160
    Likes Received:
    39
    What if the L2 exam just included some specific questions covering safe design practices and launch/prep procedures related to electronic deployment?
     
    Steve Shannon likes this.
  12. Feb 14, 2020 #762

    gtg738w

    gtg738w

    gtg738w

    FlightSketch - flightsketch.com TRF Sponsor

    Joined:
    Dec 27, 2018
    Messages:
    191
    Likes Received:
    114
    Gender:
    Male
    I think there is a lot more risk in someone’s first dual deploy flight than there is flying an H instead of a G80. It’s much more than just the electronics too. I’ve seen two flights where someone left out the charge AND the delay grain when building the motor because they thought it wasn’t needed with electronic deployment.

    A “cert” flight or whatever you want to call it with a little extra help from the RSO or a mentor would be beneficial for everyone. As long as it isn’t required for L1 (and the reverse) the impact would be pretty minimal.
     
    g.pitts likes this.
  13. Feb 14, 2020 #763

    Buckeye

    Buckeye

    Buckeye

    Well-Known Member

    Joined:
    Sep 6, 2009
    Messages:
    2,247
    Likes Received:
    184
    I started using electric deployment in MPR with an E motor, well before I got L1 and L2. We don't need more rules and certifications.

    Training for soldering? Watch a YouTube video. Done.
     
  14. Feb 14, 2020 #764

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    I don’t like the idea of additional certifications, but I agree that there needs to be better understanding of electronics and basic wiring practices.
    I could see adding a section on electronics to the L2 written test, but it would have to be done in unison with CAR and NAR. All motors above a 2560 Ns are required to have electronic recovery so that would fit.
    But it sounds like the biggest problem with electronics is getting people not to use junk. I don’t think we can do much about that.
     
    Speaknoevil likes this.
  15. Feb 14, 2020 #765

    heada

    heada

    heada

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    2,698
    Likes Received:
    206
    Gender:
    Male
    Location:
    Indianapolis, Indiana
    I find no issue with the saying that people need more knowledge and training but requiring it is not something I'd support. Adding a section to the L2 test would not be too intrusive but again, the first time they're actually required is for L3 so requiring knowledge or skill before L3 should not be mandatory.
     
    kc9qzf likes this.
  16. Feb 14, 2020 #766

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    L motors are required to have electronic recovery.
     
  17. Feb 14, 2020 #767

    mikec

    mikec

    mikec

    Well-Known Member

    Joined:
    May 9, 2009
    Messages:
    2,165
    Likes Received:
    162
    Beg your pardon? I can't fly an Aerotech L1000 with apogee motor ejection?

    It's true that most other L motors are plugged, but not this one.
     
  18. Feb 14, 2020 #768

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter

    Joined:
    Feb 3, 2012
    Messages:
    3,412
    Likes Received:
    662
    Back to the rule, I think they should have simply said that "There must be two independent switching devices (altimeter, timer, electronic or physical switch, etc.) between a power source and an energetic, at least one of which must physically disconnect power." That takes care of about 99% of the "But what about..." questions. If they later decide to allow electronic switches in lieu of physical ones, they can remove the "at least one of which must physically disconnect power" clause. It's always easier to remove a restriction than to add one.
     
    Charles_McG and Steve Shannon like this.
  19. Feb 14, 2020 #769

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    You can, but you must also have electronic deployment. Here’s the rule from NFPA 1127:

    4.10.2 A high power rocket launched with an installed total impulse greater than 2560 N-sec (576 lb-sec) shall use an electronically actuated recovery system as either a primary or backup deployment method.
     
  20. Feb 14, 2020 #770

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    I like that.
     
  21. Feb 14, 2020 #771

    manixFan

    manixFan

    manixFan

    Not a rocket scientist

    Joined:
    Feb 15, 2009
    Messages:
    1,411
    Likes Received:
    452
    Gender:
    Male
    Location:
    TX
    At the weekly 'rocket lunch' I attend one of the guys bought a sample of a screw switch he and others decided to try in light of the recent rule. I wanted to design and print a 3D mount for it since it needs some clearance on the bottom. While I had it, I tried the experiment you see below. I repeated it several times. Sometimes it turned clockwise, sometimes the reverse. The altimeter I used is a Perfectflight Stratalogger with the optional connection for a LED. I cropped and resized the video so I could make it an animated GIF for simplicity.

    This is a simple experiment anyone can try for themselves.


    Tony

    (full video available on request)
    switch-test.gif
     
    NikeMikey and John Taylor like this.
  22. Feb 14, 2020 #772

    heada

    heada

    heada

    Well-Known Member

    Joined:
    Jan 18, 2009
    Messages:
    2,698
    Likes Received:
    206
    Gender:
    Male
    Location:
    Indianapolis, Indiana
    Any idea why that rule is there? As listed above, there are (admittedly very few) L motors with delays and ejections.
     
  23. Feb 14, 2020 #773

    mikec

    mikec

    mikec

    Well-Known Member

    Joined:
    May 9, 2009
    Messages:
    2,165
    Likes Received:
    162
    Huh. This is a good example of why the TRA Safety Code should have more detail in it than expecting you to read a long document that is difficult to access. I bet that almost no one was aware of that rule, I certainly wasn't. I wonder how many other little gotchas are waiting to be discovered.
     
    kc9qzf likes this.
  24. Feb 14, 2020 #774

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter

    Joined:
    Feb 3, 2012
    Messages:
    3,412
    Likes Received:
    662
    Was that tightened fully (or backed out fully) first? I know that switch well, I find it hard to believe it would go intermittent so easily, unless the screw was closed very lightly.
     
  25. Feb 14, 2020 #775

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Sponsor TRF Supporter

    Joined:
    Feb 3, 2012
    Messages:
    3,412
    Likes Received:
    662
    Also, NFPA 1127 is not publicly available, unless you pay for it. I would bet that a good number of L2's have never seen the actual code, just the restatements from the L2 test pool.
     
  26. Feb 14, 2020 #776

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    I don’t know, Aaron. I can try to find out sometime.
     
  27. Feb 14, 2020 #777

    Steve Shannon

    Steve Shannon

    Steve Shannon

    Well-Known Member

    Joined:
    Jul 23, 2011
    Messages:
    5,442
    Likes Received:
    1,754
    Location:
    Butte, Montana
    We sent a copy to every Prefect a couple years ago. It would be nice to be able to afford to provide one to every member, but they’re $52 each now.
    It is accessible at no charge online though, even though that’s less convenient.
     
  28. Feb 14, 2020 #778

    jderimig

    jderimig

    jderimig

    Sponsor TRF Sponsor

    Joined:
    Jan 23, 2009
    Messages:
    2,987
    Likes Received:
    420
  29. Feb 14, 2020 #779

    jderimig

    jderimig

    jderimig

    Sponsor TRF Sponsor

    Joined:
    Jan 23, 2009
    Messages:
    2,987
    Likes Received:
    420
    Bad implementation of a screw switch.
     
  30. Feb 14, 2020 #780

    dvdsnyd

    dvdsnyd

    dvdsnyd

    Well-Known Member

    Joined:
    May 9, 2012
    Messages:
    111
    Likes Received:
    10
    Voyager1 and Steve Shannon like this.

Share This Page

Group Builder