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. Avast, me proud beauty! Blimey! Avast, arrr, me proud beauty! Blimey! This is for your information only. Begad! Blimey! Avast! Blimey! If you try t' build one like this, me bucko, ya bilge rat, and end up gettin' hurt, arrr, or blowin' up a battery, shiver me timbers, shiver me timbers, don't come cryin' t' me. 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. T' buttons: both t' Launch Button and t' Continuity Button are momentary push buttons. Avast! They only pass current while you are pressin' them. Well, blow me down! 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. Aye aye! T' continuity button acts like a deadman switch. Blimey! Ya scallywag! Blimey! Even with t' safety key in place, me hearties, if no one is holdin' t' controller, shiver me timbers, t' launch button will nay work.

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

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

4. Arrr! Well, me hearties, blow me down! Diode. Avast, me proud beauty! 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. Begad! Well, blow me down! Do nay use a Zenier diode. Ahoy! Aye aye! T' cathode (the side with t' band on it, 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, matey, blow me down! If your igniter is shorted, me hearties, 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. T' prevent this, I have put this diode here.

5. Begad! Blimey! Safety Key: This is a regular 1/8" mini-plug. Blimey! Blimey! Aye aye! Blimey! Inside t' plug itself are two leads. Begad! Blimey! I soldered a wire so that t' plug connects t' itself. This passes t' current through t' base o' t' plug when inserted. Avast! Blimey! Blimey! Blimey! If you build any type o' controller, arrr, arrr, 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. Ahoy! Blimey! Avast, ya bilge rat, me proud beauty! Blimey! Without t' safety key, shiver me timbers, me bucko, 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. Aye aye! Avast, me proud beauty! Blimey! I put t' Launch Button and Safety Key on top, and t' Continuity Button on t' side.

Operation

T' operation be t' same as an Aerotech Controller. Ya scallywag! First, me bucko, ya bilge rat, makin' sure that t' safety key is removed, ya bilge rat, me bucko, connect t' igniter t' t' clips. Aye aye! Insert t' miniplug, and depress t' continuity button. Begad! If everythin' is correct, you will hear t' piezo buzzer. This indicates continuity though t' igniter. Avast, me proud beauty! When ready, ya bilge rat, me hearties, 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, includin' car batteries. Aye aye! 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! 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! Begad! Before you build any device like t' one described here, make sure you understand t' theory, matey, and do nay use cheap parts. Begad! Arrr! Use your heads, ya bilge rat, arrr, people. You have no business doin' rocketry if you do nay put safety first.