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

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

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

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

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

6. Arrr! Mount t' whole thin' inside a small box. Avast, me proud beauty! I put t' Launch Button and Safety Key on top, me bucko, and t' Continuity Button on t' side.

Operation

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

Pictures o' t' finished controller will appear soon.

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