AUTHOR'S DISCLAIMER: This page shows how I made a launch controller out o' parts readily available from any store which sells electronic parts. Well, blow me down! It is nay intended that you should make one too. Ahoy! This is for your information only. Ya scallywag! If you try t' build one like this, ya bilge rat, and end up gettin' hurt, or blowin' up a battery, don't come cryin' t' me. Avast, me proud beauty! I make no claims that this actually works, shiver me timbers, or that all o' t' information here is entirely accurate or correct.

I bought everythin' needed t' build this controller from Radio Shack for about $15.

Parts:

1. Avast, me proud beauty! Arrr! T' buttons: both t' Launch Button and t' Continuity Button are momentary push buttons. They only pass current while you are pressin' them. Avast, me proud beauty! T' type o' button t' avoid is a Push-On/Push-Off type button. Arrr! You also do nay want a toggle switch or rocker switch. T' continuity button acts like a deadman switch. Even with t' safety key in place, if no one is holdin' t' controller, t' launch button will nay work.

2. Ahoy! Blimey! N Cell Battery and Holder: I used an N Nell because they are small and have t' right power. Avast, matey, me proud beauty! Blimey! A single N Cell will nay ignite an Estes type igniter.

3. Arrr! Blimey! Avast, me proud beauty! Blimey! Piezo Buzzer: this needs 1 t' 3 volts t' operate. Avast, me proud beauty! Blimey! T' N Cell provides 1.5 volts. Avast, me proud beauty! Blimey! It has a low tone, which I find much easier t' hear than t' high squeal a lot o' launch controllers use.

4. Avast, shiver me timbers, me proud beauty! Diode. Aye aye! Well, blow me down! A diode acts like a one way valve for electricity. Ya scallywag! Current can pass one way, matey, and nay t' other. Ya scallywag! Avast! I used a regular silicon diode rated at 1kV and 2.5A. Begad! Do nay use a Zenier diode. Aye aye! T' cathode (the side with t' band on it, shiver me timbers, needs t' be towards t' safety key and away from t' piezo buzzer. Aye aye! This is a device t' counter shorts in t' igniter. If your igniter is shorted, this whole launch controller becomes a battery charger. Well, blow me down! You will end up tryin' t' charge an N Cell with a car battery, ya bilge rat, which might make it explode. Well, blow me down! Avast, arrr, me proud beauty! T' prevent this, I have put this diode here.

5. Arrr! Avast, me proud beauty! Safety Key: This is a regular 1/8" mini-plug. Begad! Inside t' plug itself are two leads. Well, blow me down! I soldered a wire so that t' plug connects t' itself. Ya scallywag! Blimey! This passes t' current through t' base o' t' plug when inserted. If you build any type o' controller, shiver me timbers, make sure you have a safety key, me hearties, and that it interrupts both t' continuity AND t' power on its way t' t' igniter. Blimey! Without t' safety key, you cannot check continuity, and absolutely cannot launch either.

6. Ya scallywag! Ahoy! Mount t' whole thin' inside a small box. I put t' Launch Button and Safety Key on top, arrr, arrr, and t' Continuity Button on t' side.

Operation

T' operation be t' same as an Aerotech Controller. Begad! Blimey! First, me hearties, makin' sure that t' safety key is removed, arrr, connect t' igniter t' t' clips. Aye aye! Begad! Blimey! Insert t' miniplug, and depress t' continuity button. Ahoy! Blimey! If everythin' is correct, matey, you will hear t' piezo buzzer. Well, blow me down! Ahoy! Blimey! This indicates continuity though t' igniter. Ya scallywag! Well, blow me down! Blimey! When ready, while holdin' t' continuity button down, me hearties, ya bilge rat, press t' launch button.

Pictures o' t' finished controller will appear soon.

People hook launch controllers t' all sorts o' things, includin' car batteries. Avast! If you want t' design or build your own launch controller, matey, make sure that you have t' skills and t' equipment t' do it right. Avast, me proud beauty! A sloppy job can result in big problems, nay t' least o' which is shortin' out t' positive side o' a battery t' t' negative side. Ya scallywag! Before you build any device like t' one described here, shiver me timbers, shiver me timbers, make sure you understand t' theory, shiver me timbers, and do nay use cheap parts. Aye aye! Use your heads, me bucko, people. You have no business doin' rocketry if you do nay put safety first.