Here's some basic wiring diagrams of how the Estes controllers are wired, and how I modified mine to use LED indicators for continuity and battery connections indications. Using LED's or piezo buzzers instead of light bulbs greatly reduces the current passed through your ignitor during continuity checks, which is necessary for low-current type ignitors like the terrific Quest Q2G2 ignitors. DO remember though, if you use LED's, that they DO require the correct polarity to work-- if you hook them up 'backwards' they WILL NOT LIGHT UP even if they have power!
Wiring a basic controller of the type you're contemplating would be quite similar to these wiring diagrams below, just substituting your components in place of the Estes components in the wiring diagrams, and using heavier wire. I would also recommend a 'removable key' type of safety interlock since it's required in the model rocket safety code. If you get a key-type switch, make sure the key can ONLY be removed in the "OFF" position, as some can be removed on either the OFF or ON position. It's not necessary to use a true 'key' switch at all, as anything which physically completes the circuit is suitable-- IE the Estes "launch key" is just a piece of metal that bridges the contacts inside the controller to allow power to flow; if that piece of metal isn't there, the circuit is broken and no power can flow even if the launch button is pushed. Such commonly used 'circuit completion' type switches are the use of phono-jacks in which the lead wires have been soldered together to form a removable 'bridge' in the circuit, and I used a 110V plug with a short jumper wire inside it connecting through a 110V outlet installed in the control box with the leads going in one side of the outlet, through the plug, and out the other side of the outlet. When the plug is removed the circuit is dead.
You'll also need a 'momentary on' type switch for a launch button-- but these are readily available at auto supplies as 'horn buttons' or at Radio Shack.
Also, a TERRIFIC 12V power supply is a car jumper battery pack-- they are HIGHLY portable, use a great capacity gel-cell battery that won't spill or leak, and can take considerable deep discharge and won't sulfate up like a regular lead-acid car battery will, and they're easily chargeable in either the car or the house, and they serve double-duty when not needed on the launch field by riding in your car trunk in case your car battery goes down, or if you leave the lights on, or cold weather weakens your car battery and you need a boost to get started. They are fairly inexpensive (usually $40 and up) but HIGHLY useful and you just can't get a more portable, self-contained, and handy rocket launching power supply IMHO.
Good luck! OL JR
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