[NRV Rocketry] Questions about outfitting an avionics bay with power-safety flags

[Thomas Weeks]

Good points Mike! Thanks for the suggestions. :)

Tweeks

On Wednesday, July 06, 2011 08:40:56 pm Mike Ficco wrote:
> Hello Tweeks,
> 
> Personally I've always either used the voltage selector rotary switches you
> linked to, or used home-brewed screw switches.  I'd not feel terribly
> comfortable with audio jack switches because they are not designed to
> carry much current, and because you pretty much need the plug to change
> the state of the switch.  I've been in the situation where someone had
> recovered my rocket and I had to describe to them how to power down the
> electronics over the phone.  That would be difficult with an audio jack
> setup.
> 
> I'm also not a fan of linear "slide" switches because of the ease with
> which they can be accidentally actuated.  One must be very careful with
> mounting orientation to minimize the changes for an anomalous high
> acceleration event such as a cato or sudden change in AOA to actuate the
> switch.
> 
> Cheers,
> Mike
> 
> On Wed, 06 Jul 2011 00:33:14 -0400, Thomas Weeks <tweeksjunk2 at theweeks.org> 
wrote:
> > This is a question for you high power guys who have been shooting H and
> > up birds for years.
> > 
> > Background:
> > -------------
> > So my first HP rocket is about ready to fly... and I plan on using it to
> > get my L1 (H) and L2 (J) certifications. The L1 is no problem. Up, pop,
> > float down. But as most of you know.. L2 certification also requires a
> > written test (no problem) as well as "Active recovery", or a way of
> > measuring your altitude and ejecting multiple chutes at precisely the
> > right times to safely recover my rocket.
> > 
> > Well.. I've now mostly built my avionics bay, or "e-bay" and wired in a
> > GWiz LCX flight computer:
> > http://www.facebook.com/photo.php?pid=1049573&l=3b9cc7e689&id=1844028171
> > http://www.facebook.com/photo.php?pid=1052820&l=fde4de7d63&id=1844028171
> > http://www.facebook.com/photo.php?pid=1052821&l=8f9d1e56c2&id=1844028171
> > http://www.facebook.com/photo.php?pid=1052825&l=878029acee&id=1844028171
> > http://www.facebook.com/photo.php?pid=1052823&l=079bcf0bff&id=1844028171
> > http://www.facebook.com/photo.php?pid=1052824&l=d39d643ca4&id=1844028171
> > 
> > Here are some other pictures of other people's e-bay construction and
> > products:
> > http://www.vanderbilt.edu/USLI/2011/media.php?gallery=jan_19_2010
> > http://www.apogeerockets.com/electronics_bays.asp
> > http://www.rocketryplanet.com/content/view/2960/95/#axzz1RIL7aYxk
> > 
> > 
> > My Question:
> > -------------
> > Anyway.. my question for Bob and other experienced Rocketeers..
> > 
> > What should I use for my flight computer's power safety switch?
> > 
> > So you're supposed to have a power arming safety circuit to ensure that
> > your ejections charges don't blow before you launch the thing... They
> > usually look something like this:
> > 
> > http://aeroconsystems.com/cart/products/RBF4-47-10.html
> > 
> > And are hung off something like a 1/8th " audio jack (where the normally
> > closed circuit is open when the audio plug is in... and removing it
> > completes (or closes) the circuit.. and powers up the computer). 
> > However.. I hear that the flight vibration can really make those switch
> > contacts bounce around, which can reset the flight computer.. which
> > leads to big expensive crashes. So a lot of folks use these high-G rated
> > switches like this:
> > http://aeroconsystems.com/cart/products/PCB_Screw_Switch-110-0.html
> > or
> > http://www.aeroconsystems.com/electronics/switches.htm
> > 
> > Not nearly as cool/sexy as the "yank it out" audio plug that I want to
> > use. :)
> > 
> > 
> > So what do you other HP folks recommend? Slide switches? Hard wired
> > toggles? Audio jack/plugs?
> > 
> > Tweeks
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