Remote Igniter System

[Snowman]

So I am wanting to build a remote igniter system for model rockets among other things. and I have picked up most of the parts already just lacking a box. I am contemplating a second battery holder in series to bump it from 6v to 12v. but here is a schematic I drew up real quick and you more experienced than I can trouble shoot, ask questions, make suggestions, and tear me apart if you feel necessary.

I rotated this before I uploaded it and it still uploaded sideways I will try and fix that but until then here it is

http://knoxware.org/snowman/IMG_20120605_100503.jpg

[TLHarrell]

My old rocket box has a barrel key switch for arming, which then lights up multiple flashing red LEDs and an audible alarm. The launch switch is actually dual push buttons in series.

Rocketry is fun, but the nuts who run California have made it very difficult and expensive as a hobby. I haven't launched in years.

[Snowman]

My old rocket box has a barrel key switch for arming, which then lights up multiple flashing red LEDs and an audible alarm. The launch switch is actually dual push buttons in series.

Rocketry is fun, but the nuts who run California have made it very difficult and expensive as a hobby. I haven't launched in years.

take it apart and take pictures haha

[mDust]

So what actually ignites the motor? A make-shift spark plug or super-hot filament of some sort?

[Snowman]

NiChrome wire, it arcs out and creates a lot of heat between 5 and 16 volts if I remember right. You can also use steel wool with match tips or a several various other things.

http://www.hobbylinc.com/rockets/group/igniter1.gif
http://www.robotroom.com/Launch-Controller/Estes-model-rocket-igniter-before-and-after-launching.png

[mDust]

An electric match...nice.

I would add a second button in series (like TLHarrell mentioned) to actually launch just for 'nanny' safety reasons. It's better to have too much safety than to accidentally take a rocket to the face.

[TLHarrell]

And the audible warning of being armed is nice too. Gives everybody a heads up if the controls are live. I was also occasionally carrying a gel pack battery and strobe light when I was out with friends doing many launches. That is easily switched with a small relay. You shoot more than one or two, and crowds show up.

I'll have to see if I can find my last box. I think it's around the garage somewhere.

[Snowman]

One safety is enough, there are two in play here a brain and a safety toggle. My store bought remote came with far less many moons ago I am not overly concerned with adding more complicity to this.

I redesigned and cleaned up the diagram yesterday let me know if it still looks like a good circuit or not.

http://knoxware.org/snowman/IMG_20120606_081141.jpg

[TLHarrell]

Firing LED not needed. You won't be looking at it when the rocket is launching. Now, a continuity check LED, that's useful. Lights up when system is armed and the igniter is good.

[Snowman]

I want it so that I have visual confirmation that the voltage is going out to the device in case of a non ignition.

[TLHarrell]

Put the "firing LED" in parallel with the firing switch with a resistor large enough to drop the voltage below that which makes the igniter burn. When it's armed and you have continuity along the entire line (line is good, and igniter is hooked up right), the LED will light up. When you hit the fire button, it bypasses the LED and drops the full pack voltage down the line.

On your schematic, move the LED connection R1 to before the switch S2.

And get yourself a really, really cool set of switches/buttons for it.

[Snowman]

Put the "firing LED" in parallel with the firing switch with a resistor large enough to drop the voltage below that which makes the igniter burn. When it's armed and you have continuity along the entire line (line is good, and igniter is hooked up right), the LED will light up. When you hit the fire button, it bypasses the LED and drops the full pack voltage down the line.

On your schematic, move the LED connection R1 to before the switch S2.

And get yourself a really, really cool set of switches/buttons for it.

I think I see what your getting at. I will take it back to the drawing board again and call this version 1 and be back with version 2 tomorrow.

[Snowman]

http://knoxware.org/snowman/IMG_20120607_101135.jpg

[TLHarrell]

Looks good to me.

[Snowman]

Now to get my enclosure, second battery pack, resistors, and decide if I want a bunch of wire or use a breadboard.

[TLHarrell]

That would be super easy to just point-to-point wire if your buttons, LEDs and wire jack are all panel mount. As far as a battery holder (if your case doesn't have battery holder built in), look into attaching it to the inside of the case with adhesive velcro and use a 9V battery clip to connect the battery pack to the controller wiring. Makes battery changes a breeze. I'm just tossing these ideas in here from experience.