AUTHOR'S DISCLAIMER: This page shows how I made a launch controller out o' parts readily available from any store which sells electronic parts. It is nay intended that you should make one too. Begad! Blimey! This is for your information only. Avast, me proud beauty! Blimey! If you try t' build one like this, matey, and end up gettin' hurt, me bucko, or blowin' up a battery, ya bilge rat, don't come cryin' t' me. Arrr! Blimey! I make no claims that this actually works, 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. Well, blow me down! Begad! T' buttons: both t' Launch Button and t' Continuity Button are momentary push buttons. Avast, me proud beauty! They only pass current while you are pressin' them. Blimey! Well, blow me down! T' type o' button t' avoid is a Push-On/Push-Off type button. Avast, me proud beauty! Avast, me proud beauty! You also do nay want a toggle switch or rocker switch. Begad! T' continuity button acts like a deadman switch. Avast! Well, blow me down! Even with t' safety key in place, me hearties, me hearties, arrr, if no one is holdin' t' controller, shiver me timbers, t' launch button will nay work.

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

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

4. Diode. Begad! A diode acts like a one way valve for electricity. Arrr! Current can pass one way, and nay t' other. Blimey! Aye aye! I used a regular silicon diode rated at 1kV and 2.5A. Well, me bucko, blow me down! Do nay use a Zenier diode. 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. Well, blow me down! Arrr! If your igniter is shorted, this whole launch controller becomes a battery charger. Begad! You will end up tryin' t' charge an N Cell with a car battery, shiver me timbers, which might make it explode. Blimey! T' prevent this, I have put this diode here.

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

6. Aye aye! Mount t' whole thin' inside a small box. Blimey! I put t' Launch Button and Safety Key on top, matey, and t' Continuity Button on t' side.

Operation

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

Pictures o' t' finished controller will appear soon.

People hook launch controllers t' all sorts o' things, arrr, includin' car batteries. Avast! Blimey! If you want t' design or build your own launch controller, shiver me timbers, shiver me timbers, shiver me timbers, make sure that you have t' skills and t' equipment t' do it right. Avast! 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. Arrr! Before you build any device like t' one described here, me hearties, make sure you understand t' theory, me bucko, me hearties, me bucko, and do nay use cheap parts. Use your heads, ya bilge rat, me hearties, people. Begad! You have no business doin' rocketry if you do nay put safety first.