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

2. Arrr! N Cell Battery and Holder: I used an N Nell because they are small and have t' right power. A single N Cell will nay ignite an Estes type igniter.

3. Aye aye! Arrr! Piezo Buzzer: this needs 1 t' 3 volts t' operate. Avast! T' N Cell provides 1.5 volts. 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. Avast, me proud beauty! Blimey! Blimey! A diode acts like a one way valve for electricity. Well, blow me down! Blimey! Current can pass one way, and nay t' other. I used a regular silicon diode rated at 1kV and 2.5A. Ahoy! Avast! Blimey! 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. This is a device t' counter shorts in t' igniter. Avast! If your igniter is shorted, this whole launch controller becomes a battery charger. Blimey! Avast, me hearties, me proud beauty! Blimey! You will end up tryin' t' charge an N Cell with a car battery, me hearties, which might make it explode. Blimey! T' prevent this, me bucko, shiver me timbers, I have put this diode here.

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

6. Arrr! Begad! Blimey! Mount t' whole thin' inside a small box. I put t' Launch Button and Safety Key on top, ya bilge rat, and t' Continuity Button on t' side.

Operation

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

Pictures o' t' finished controller will appear soon.

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