Most people will use the screw terminal blocks for the outputs, they’re convenient but you must
be careful to check their tightness before every flight. We’ve found that simply wire-wrapping
the igniters to a “pigtail” wire soldered to the board works very well for smaller rockets. It also
can help reduce the profile a little bit by eliminating the screw terminal blocks. By soldering the
pigtails to the board rather than having screw terminal blocks, you also eliminate the possibility
that the wire may work loose from the terminal in flight.
We recommend using #22-#26 gauge wire for wiring to the Quasar board, we like to use the #24
gauge stranded wire that’s found in Cat-5 network cables. It’s cheap, easy to find, and just the
right size. It’s also twisted together in nice solid-striped pairs, so it’s easy to tell the “+” from
the “-“ wire, and is color-coded to make it easier to figure out which wire goes where. If you
can, get the “plenum” cable, since it has a Teflon jacket and doesn’t melt as easily when you
solder to it as the standard “riser” cable. You can also use solid wire, but solid wire is harder to
work with and has a tendency to break after being bent a few times. These breaks can be a pain
to find, because they are typically inside the insulator jacket where you can’t see them.
If you use stranded wire, you MUST TIN THE WIRES BEFORE SOLDERING TO THE
BOARD. This is to prevent stray “whiskers” of wire strands from coming loose and bridging
pads, or breaking off and landing on the board in some random place. We’ve seen the results of
this happening, it’s not pretty, and they can be very hard to find if the lodge underneath the
processor chip or in some other hidden spot on the board.
If you build the board with the terminal block option, be sure to tin whatever wires you are using
for your igniters before you insert them into the terminal block. Better yet, get some pin ferrules,
and solder and/or crimp them to the pins. Loose strands here can prevent deployments, and they
can also lodge underneath components and cause a malfunction during flight. That would be
bad…
Last, but not least, we strongly recommend that all wiring on your sled be zip-tied or otherwised
securely attached to the sled so that there’s no chance of any wires coming loose in flight.
We’ve seen it happen, and the results are not pretty.
About Switches…
The Quasar is designed so that by default it will not self-arm itself. If you power it up, it will sit
there on the Status page forever, changing the validation code every 60 seconds… you have to
actually arm it using the validation code in order to start a flight. In addition, the unique dual-
ended deployment output prevents any significant current from getting to the igniter until it’s
armed and actually in-flight, and the first output event occurs.
Because of this, for most flights using electronic deployments up through NAR/TRA Level 2
you do not necessarily need a separate power switch. You can simply connect the battery to a
locking connector such as a JST connector and you’re ready to go until you arm it on the pad.
This makes your AV bay build easier and smaller, and of course it makes your pre-flight
procedure a lot simpler.
NAR and Tripoli rules require that the “energetics” on a rocket are electrically disabled until
you’re on the pad. The Quasar is different than most other altimeters because it has dual-ended
switching on the deployment outputs: BOTH the “+” and the “-“ side are switched off, leaving
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