circuit design help

[[email protected]]

I am a 13 year old tinkerer i have built and played with various basic
circuit components (transistors, resistors, capacitors, LEDs, etc.,
etc,) However i plan on making a device to make that is used to launch
model rockets (Estes) that use a igniter that is triggered by running
a current through it. I want to create a circuit that allows me to
flip a Single Pole, Single Throw (SPST) switch, (http://
www.kpsec.freeuk.com/photos/rapid/swspst.jpg). once this switch is in
the on position a ready/warning light comes on then the person using
the device will push a momentary switch (http://www.kpsec.freeuk.com/
photos/rapid/pshpsh.jpg) the device then after 5-10 seconds activates
a relay which will set off the fuse and launch the rocket. All this
could be housed in a project box from radio shack. I am a complete
noob please include some sort of labeled diagram and maybe a part
list.

With much thanks,
Scats

PS: please make as simple as possible with parts available at radio
shack.

 

[Howhurley]

I am a 13 year old tinkerer i have built and played with various basic
circuit components (transistors, resistors, capacitors, LEDs, etc.,
etc,) However i plan on making a device to make that is used to launch
model rockets (Estes) that use a igniter that is triggered by running
a current through it. I want to create a circuit that allows me to
flip a Single Pole, Single Throw (SPST) switch, (http://www.kpsec.freeuk.com/photos/rapid/swspst.jpg). once this switch is in
the on position a ready/warning light comes on then the person using
the device will push a momentary switch (http://www.kpsec.freeuk.com/
photos/rapid/pshpsh.jpg) the device then after 5-10 seconds activates
a relay which will set off the fuse and launch the rocket. All this
could be housed in a project box from radio shack. I am a complete
noob please include some sort of labeled diagram and maybe a part
list.

With much thanks,
Scats

PS: please make as simple as possible with parts available at radio
shack.

Hey, I love rocketry! Got my first start with aerodynamics with it.
Lots of years ago. Anyway, the first question: What kind of igniter
current do you need? There are a couple different kinds, and it
matters. Next...Why do you want to delay 5-10 seconds? Sounds a
little scary to me. Easy to do, just I'd hate to have a hot rocket on
a launch pad when someone comes over and says "gee, what's this???"
So safety might be a concern.

While you are looking those things up, here is a link:
http://www.esteseducator.com/Pdf_files/1924_launch.pdf It's got a lot
of (old, but true) info on launch circuits.

 

[[email protected]]

I was thinking i could set the box down and a bout 10ish feet and run
away almost like a fuse but an electronic version. i'm not sure the
voltage but i should be able to play with it cause its on a relay but
12 volts should be more than enough. Heres what I use (http://
www.estesrockets.com/products.php?number=302301)

 

[Ecnerwal]

I am a 13 year old tinkerer i have built and played with various basic
circuit components (transistors, resistors, capacitors, LEDs, etc.,
etc,) However i plan on making a device to make that is used to launch
model rockets (Estes) that use a igniter that is triggered by running
a current through it.
Fine.

I want to create a circuit that allows me to
flip a Single Pole, Single Throw (SPST) switch, (http://
www.kpsec.freeuk.com/photos/rapid/swspst.jpg). once this switch is in
the on position a ready/warning light comes on

You missed a step of basic rocket safety here. You need a keyed switch
(either before, or as, this switch) so that you can take the key with
you whenever you approach the launchpad, so that you are _certain_ that
the launch circuit is dead, and cannot be accidentally turned on by
someone else. You should use the type of keyed switch that can only have
the key removed when it is off. Personally, I chose to put in both the
keyed switch AND another switch, both of which have to be on to make the
launch button live.

then the person using
the device will push a momentary switch (http://www.kpsec.freeuk.com/
photos/rapid/pshpsh.jpg) the device then after 5-10 seconds

Seriously not fine. A lot can happen in 5-10 seconds. If you are trying
to get further away (perhaps to take an angle measurement), use a longer
wire, and/or some helpers to take measurements. The person pushing the
launch button is responsible to be sure that it is safe to launch, and
thus an automated launch delay is not an acceptable solution, as it
could become unsafe to launch between the time the button is pushed and
the time the rocket actually launches.

PS: please make as simple as possible with parts available at radio
shack.

Well, mine is from parts found in an old Chevy and an old Saab, or was
it a Volvo? Still gets used a couple of times a year. I keep thinking
I'll come up with a new version, but I haven't actually needed to, so
the first one I built (~30 years ago) stands. Made it to replace the
unreliable plastic thing that came with the first rocketry kit I got.

 

[Ken S. Tucker]

I was thinking i could set the box down and a bout 10ish feet and run
away almost like a fuse but an electronic version. i'm not sure the
voltage but i should be able to play with it cause its on a relay but
12 volts should be more than enough. Heres what I use (http://www.estesrockets.com/products.php?number=302301)

A friend of ours has a site
http://www.nakka-rocketry.net/
you may want to review. He uses radio to
launch, but those are large amateur rockets.

For your application, I've used 100-200' telephone
wire to trip for ignition.
If you must have a timer, consider a 1 RPM motor
that turns a hard wire to make switch contact on
a flexible wire that is all visible.
That way you can watch the wire turning prior to
ignition.

Just to add, it's a lot easier to play a tape recording
of all your steps going into launch, like a countdown.
Things like wind, range safety, observers confirmed
at the locations, the ignition procedure etc. oh yeah
and play Major Tom between the instructions!
Ken

 

[Marra]

Why not just use a match ?

 

[[email protected]]

Why not just use a match ?

cause i don't got any visco fuse or any fuse really plus its funner if
you build/solder the circuit yourself

 

[Eeyore]

cause i don't got any visco fuse or any fuse really plus its funner if
you build/solder the circuit yourself

Funner !

That's a new one.

Graham

 

[[email protected]]

Funner !

That's a new one.

Graham

it maybe new but i am a DYI kindof guy