How do I Build a 6/12 volt launch controller?

[rubenmromero]

Walked through RadioShack and have an idea. Need professional help/advice thuogh.

[GDJ]

Easy. You need a high amperage automotive relay, a momentary push button, key switch, LED lamp (single diode 12v), some 6 gauge wire with battery alligator clips, 50 feet of 16 gauge 2 conductor wire, and a project box big enough to fit it all in.

Ready?

[eggplant]

You most certainly do not need a relay! You need a battery, a switch, a button, and some wire. Just get all of that and then I will help you put it all together. Welcome to the forum!

[bobkrech]

Easy. You need a high amperage automotive relay, a momentary push button, key switch, LED lamp (single diode 12v), some 6 gauge wire with battery alligator clips, 50 feet of 16 gauge 2 conductor wire, and a project box big enough to fit it all in.

Ready?

WHAT? Do you have a clue how big 6 gauge wire is? It is totally unnecessary.

You don't need a relay, but if you use one this is all you need http://www.allelectronics.com/make-a...E-RELAY/1.html and this is the wiring http://www.allelectronics.com/make-a...E-RELAY/1.html The relay will pass 100 amps in a launcher applicaion, and multiconductor 14 gauge wire is plenty for that current as well. The relay draws about 0.1 amp so 100' of 18 gauge zip cord is plenty here. A standard superbright LED in series with a 500-1000 ohm resistor is all you need to limit the current through the LED to 10 to 20 ma.

If you don't use a relay 16 gauge zip cord is fine for runs to 50'.

You do not need a key switch. You need a removable interlock.

Search the forum and the archive for all kinds of launcher plans.

Bob

[GDJ]

WHAT? Do you have a clue how big 6 gauge wire is? It is totally unnecessary.

You don't need a relay, but if you use one this is all you need http://www.allelectronics.com/make-a...E-RELAY/1.html and this is the wiring http://www.allelectronics.com/make-a...E-RELAY/1.html The relay will pass 100 amps in a launcher applicaion, and multiconductor 14 gauge wire is plenty for that current as well. The relay draws about 0.1 amp so 100' of 18 gauge zip cord is plenty here. A standard superbright LED in series with a 500-1000 ohm resistor is all you need to limit the current through the LED to 10 to 20 ma.

If you don't use a relay 16 gauge zip cord is fine for runs to 50'.

You do not need a key switch. You need a removable interlock.

Search the forum and the archive for all kinds of launcher plans.

Bob

Okay, eggplant and bobkrech, yeah I do know how big 6 gauge wire is. The copper conductor just under 5.5 mm in diameter. I've been a Heavy Truck Technician for the last 17 years. Read my Member's Information. I'm not an idiot, and I do design things that may be considered overbuilt, but they are 100% reliable.

Here is my rationale for my proposal, if you're interested:

1) Relay - Can pass as much current as possible to the igniter(s). Don't have to rely on a light duty automotive switch to transfer a hefty amount of current, even if it's under one second.
2) Pushbutton momentary switch - Pretty obvious. Push down, makes contact. Release the button, current stops.
3) 12V LED: Self limiting for current, thanks to the current limiting resistor. 20mA is about right, so you have very little current going to, say, a Quest ignitor.
4) Alligator clips with 6 ga (oh hell, lets shrink it to 8 ga) wire - Alligator clips hook on the posts of a battery, and making good proper contact. Heavy wiring is more for being robust.
5) 50 or so feet of 16 ga 2 conductor cable - Gives you all the room you would need from little 1/4 A rockets to HPR.
6) Key switch - Turns the whole unit off. Acts like a safety key.


Not really aiming this at eggplant, but bobkrech, you sounded off like I was a complete idiot without asking for any reasons as to why I suggested the parts I did. You attacked me. I don't appreciate that.

[jus_rockets]

What type of battery are you guys using with your 12v launch systems?

[GDJ]

What type of battery are you guys using with your 12v launch systems?

I prefer Lead Acid car batteries. Don't have to charge them that often, lots of current capacity, pretty flexible for ambient temperatures (ie plenty of current when it's -20C).

I don't like the weight I have to lug around, but at least it only has to move to the car, launch site, back in car, then home. I can eat my wheaties for that.

[hornet driver]

one 1972 chevy p/u, 100 ft speaker wire, one set vice grips,one pair rubber gloves, one roll duct tape---wait a minute--I think the guy trying to launch cats gave me this------on a serious note---I've thought about a small mower/motorcycle battery in the future---thoughts?

[chadrog]

What type of battery are you guys using with your 12v launch systems?

A much more portable option is a motorcycle / lawn tractor battery. They can be had for twenty to thirty bucks and light anything as well as a larger battery. My battery stays permanently installed in my 12v launch controller, hinged lid allows access for charging.

[rubenmromero]

Ok.Thanks for all the info from all.Very much appreciated.Only thing I am not clear about is how to wire in the lamp/led for continuity.