[TriEmbed] Rocket derby help

[Shane Trent]

Craig,

I suggest changing to a 12V battery. A small SLA should fit the bill and
offer plenty of launches per charge.

Shane

On Mon, Jan 30, 2017 at 10:25 PM John Vaughters via TriEmbed <
triembed at triembed.org> wrote:

> Craig,
>
> I do not know what it takes to light the fuse, but right off the bat, your
> currents seem tiny. Are you sure you got the scale right? Also, cat 5 cable
> does not transmit alot of current, but it may be enough. I just do not know
> how much current you need. I also do not have the specs on the igniter and
> what voltage/current is proper. I think you need to start with the specs
> for the igniter, look that up first. Then consider upping the voltage at
> the button box to get the proper voltage at the igniter. If it worked
> before then it may be as simple as verifying the specs of the igniter and
> the provided voltage, but be careful if it is truly only cat 5 cable. It is
> very low current cable.
>
> Did I miss the email about the car race results and solution? If not,
> please let us know how it went.
>
> Thanks,
>
> John Vaughters
>
>
> On Monday, January 30, 2017 9:43 PM, Craig Cook via TriEmbed <
> triembed at triembed.org> wrote:
>
>
> Now that Pinewood derby is over, onto my next challenge.
>
> Last year I was launch master for our Cub Pack.  We have been having
> problems with our rocket launch system.  6V large square battery powers the
> system.  There is a rotary switch where you can select from position 1,2,3
> or 4.  This box is connected via 45 feet of cat 5e wire to junction box
> (DB9 serial connectors attach from the launch box to cable, and another one
> to the junction box).  The junction box is split out to 4 sets of wire with
> alligator clips.  These clips attach to the rocket fuse (1,2,3 or 4).  The
> Cub presses a button on the launch box, energy is dumped into the fuse and
> the rocket should take off.
>
> The last few years we have had problems with the fuse not getting enough
> energy to burn fast enough and launch the rocket, result is an unhappy Cub.
>
> I cut off and re-soldered the alligator clips thinking that would solve
> the problem.  It didn't.  I checked and I have 0 resistance from the
> junction box to alligator clips, so I think my soldering was ok.
>
> I measure 1.2 ohms of resistance from the launch box to the junction box
> going over the 45 feet of wire.
>
> Battery has 6.5 Volts, at the junction box I measure 4.19 Volts.
>
> Battery has 0.005 Amps, at the junction box I have 0.003 Amps.
>
> Is there a way to store energy at the junction box, then have it released
> when a switch is pushed?  I think that is what a capacitor is for, but not
> sure.
>
>
> I was considering replacing the cat 5e wire and DB9 connectors with RJ45
> ones.  Would that help?
>
> No idea how old the batteries are, are the Amps too low?
>
> Whoever made this setup knew what they were doing.  It has been well put
> together.
>
>
> Thanks
>
> Craig
>
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