So why have a controller anyway? As stated by the NAR rocket safety code a controller with a safety interlock should be used. This isn't just to complicate things but it really is for safety. With a controller with a safety it is pretty much impossible to have accidental ignition like it would be with just a simple switch or just connecting it to a battery.
What you will need:
hot glue gun
pliers and wire cutters
xacto / razor
momentary switch, I have two but only one is needed
small bolts with two nuts to fit
battery or battery holder
molex connector or any connector that you have a male a female end to
here's a link to the NAR site for reference
Step 1: Layout and Install
Layout your components and mark where you need to cut. After cutting your holes make sure everything fits and mount them in place.
Don't forget to make the holes for your post on the front.
Step 2: Connect
All components of the launcher need to closed for the launcher to work.
Step 3: Finishing Up
Install your battery and test.
I have added a schematic with a rocker and leds, neither leds are really needed but nice to have and leds always make you project look better. More lights and swithces.
I used two momentary switches on mine for added safety as I have little ones launching with me. Attach a lanyard or something to the key and you can hang it around your neck.
The line going out to the rocket is around 25 to 30 feet, plenty of room.