Simple Plans for a 12V Wireless Single Launch Controller

I've got the 12v battery jumper power pack from Harbor Freight, but not a clue past that. Looking for something simple for a single launch pad and a 100 foot wireless range.

Mike Momenee
TRA #12430 L3

If you only need 100 ft for a single pad, why not just use a small box as the controller and 100 ft of lamp cord for the wire. Simple, cheap, and will work just fine for a single pad.

I have 2" x 2.5" x 4.5" box I use as a controller. A phone plug as the removable interlock and a LED for power, a momentary toggle switch as the arm switch, a push button and LED for continuity and a momentary push button for a launch button. I have to hold the arm switch on and push the launch at the same time. Just a little more safety.

I only have 50 ft of lamp cord coming out the front of the box with clips on it for the rocket. There is about 6 ft of cord coming out the other side for the power. I also use a car starter (12v battery jumper power pack) so the positive lead from the box is a foot shorter then the negative lead. That way if you accidentally pull the cord, the two battery clamps on the car starter will be a different lengths and won't hit each other and spark and arc all over the place. When I'm done, I just curl everything into a single loop and it's easy to store.

I'm sure it would work just as well with 100 ft of cord.

100 feet is exactly what I'm looking for. I assumed (ass/u/me) that 100 feet was too long a run of wire to work properly. I already have a 12V wired controller with 40 feet of wire. I'll add 60 feet of lamp wire and give it a go. Thanks!

jmmome said:

100 feet is exactly what I'm looking for. I assumed (ass/u/me) that 100 feet was too long a run of wire to work properly. I already have a 12V wired controller with 40 feet of wire. I'll add 60 feet of lamp wire and give it a go. Thanks!

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At 100', you really would need a "relay" launcher.

That way the 100' long wires would only have to carry the small current to pulll in the relay - not the many amps to fire the ignitor.

Search TRF for "relay launcher plans"

Here is one I put together. I have walked out to 250/300 feet without losing signal. Search ebay for 315MHz relay (there are a zillion of them). SLA 12V battery launches them all day.

jmmome said:

100 feet is exactly what I'm looking for. I assumed (ass/u/me) that 100 feet was too long a run of wire to work properly. I already have a 12V wired controller with 40 feet of wire. I'll add 60 feet of lamp wire and give it a go. Thanks!

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100' of 16 ga wire (like you would get if you bought a 100' 2-wire outdoor extension cord from your local hardware store) should have a resistance of under one ohm, round-trip. If you're using a 12V controller, the extra length shouldn't be a problem for your battery or igniter.

Handeman, I'd like to see your launch controller. I'm thinking of making my own to very similar specs. I'm not an electronics handyman, so simple "for dummies" diagrams and component descriptions work best for me. I have a 12V gel-cell that I'll be using for power.

TangoJuliet said:

Handeman, I'd like to see your launch controller. I'm thinking of making my own to very similar specs. I'm not an electronics handyman, so simple "for dummies" diagrams and component descriptions work best for me. I have a 12V gel-cell that I'll be using for power.

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I'll take a few pics and draw up the schematic and post it as soon as I can. Sorry I'm so late on replying, I've been working 14 hr days and have company coming in from Florida in a few minutes.

No problem. I work a week on, week off schedule, and spend more time on the www at work than I do at home. :wink:

Here are some pics and the schematic of my launch controller.

I cut the Velcro tab off an umbrella and use that to bundle the controller and wire to make it easy to transport. I also put a wrist strap on the safety key so you can slip it on your wrist so you don't forget to remove it after you launch. It also keeps you from losing it.



The positive lead going to the battery is longer then the negative, that keeps the two from contacting each other if you pull on the wire, which you will do.



Here are the buttons, etc. and labels. I just used masking tape and a pen. To operate this, you must hold the momentary arm switch ON when you press the launch button. This makes it a two handed operation which I though would make it a more positive control for launching and safer.



Here's the schematic.


I show 470 ohm resistors with the standard red LEDs. You can use 510 ohm resistors if you want. The difference in LED brightness will be hard to notice and there should be less then 2 milliamp difference in current flow. Either one will get you about 22 milliamps of current when you do the continuity check. The resisters can be 1/8 watt and 10%, or whatever you happen to have.

I do recommend you use 16ga lamp cord for the power and igniter clips. I also recommend you use 16ga wire for any internal wiring between switches in the box. The wire that connects the LEDs and resistors can be as small as 24ga. since there is such small current going through those items.

Thanks again.