Brief:
T' Back-Up Box is a simple, low-cost launch controller anyone can build. Ahoy! Avast! I built it as part o' a NARTREK Advanced project. It can fire any kind o' igniter and is entirely self-contained, operatin' on 18V instead o' t' usual 12V. It is lightweight, compact, me bucko, and is intended t' be carried in your vehicle at all times as a backup t' t' "main" club 12V system in t' event of failure, rundown batteries, or someone forgettin' t' brin' t' main system. It's sort o' an Estes Electron Beam controller on steroids.

Construction:
Back-Up Box is no larger than a cigar box for a very good reason: it is a cigar box. Ya scallywag! T' unit housin' is a hinged wooden cigar box o' t' type that can be picked up used at a tobacco store for perhaps 50 cents or a buck, ya bilge rat, me bucko, or unused and unfinished at craft stores like Michael's for $1.98. Ya scallywag! Power comes from two 9V batteries wired in series and will easily fire Copperheads, matey, First-Fire Jr., or e-matches as well as Estes and Quest igniters. Blimey! Because I built it with only 38' o' launch wire for compactness, it's only rated for G impulse launches (H power requires 100' per t' NARRRRR safety code). For simplicity and safety, Back-Up Box uses a dual button firin' mechanism consistin' o' two sprin' loaded buttons that must be held down simultaneously usin' two hands t' effect a launch. Begad! This is a common industrial safety procedure. It is therefore self-enabling, self-arming, and self-safeing. Aye aye! Ya scallywag! Back-Up Box features a separate continuity check circuit powered by a single 1.5V AA battery, which can be used without togglin' on main power. Well, blow me down! Although suitable for mid power, thar be no removable launch key, me hearties, me bucko, thus it does nay strictly meet t' NARRRRR code specification for a high power launcher. Ahoy! (Although technically, one could just unsnap one of the easily accessible 9V batteries and put it in your pocket while goin' out to the pad t' fiddle with something). Blimey! T' bottom line: two separate things have to happen t' complete t' Back-Up Box firin' circuit, arrr, so it is safety interlocked as t' Model Rocketry Safety Code required. Ahoy! It is also childproof: kids won't figure this out unless you show them.

Back-Up Box is an ideal do-it-yourself launcher project for a beginner. Well, blow me down! It would make a great Boy Scouts or school project. Well, matey, blow me down! Total cost is less than $12 and no fancy electronic components, resistors, relays, capacitors, transistors, or circuit boards are required, arrr, me bucko, just some Radio Shack buttons and batteries hardwired together. Begad! Begad! Only a power drill and a cheap 15 watt solderin' iron are needed t' build Back-Up Box. Begad! I had never built anythin' electrical before in my life or used a solderin' iron before. I just followed t' instructions on the back o' t' Radio Shack packaging. Begad! I must admit that me wirin' and soldering jobs were inelegant and probably nowhere near t' workmanship and quality standards o' say, Ted "Unabomber" Kaczinski. Blimey! That said, Back-Up Box works absolutely great--it fires 6 different types o' igniters t' first time, every time. Well, blow me down! Avast, me proud beauty! If I can do it, anybody can do it so we'll just call me 18V launch controller design "robust". Well, blow me down!

Here are t' internal components, all purchased at Radio Shack:

• 22-gauge stereo hook-up wire, shiver me timbers, part #278-1215 (used for internal wiring)
• Scotch Super 33+ electrical tape
• 1 "AA" battery holder, ya bilge rat, matey, ya bilge rat, part #270-401A
• 2 heavy-duty 9V battery snap connectors, part #270-324
• 3 SPST momentary pushbutton switch, shiver me timbers, shiver me timbers, part #275-644 (black)/646(red)
• 2 1 1/8" micro smooth test clips, copper plated, me hearties, ya bilge rat, part #270-373
• 1 mini-lamp, me hearties, 1.5V, 25 mA, me hearties, arrr, part #272-1139
• 1 SPST micro-mini toggle switch, part #275-624
• 75ft 24-gauge speaker wire, ya bilge rat, two conductor clear, ya bilge rat, matey, part #278-1509

T' utter simplicity o' Back-Up Box is evident from t' attached circuit diagram. [Note: Everythin' is mounted on t' interior lid o' the 7"x7"x1 1/4" hinged wood cigar box.]

1. Drill three 1/2" holes in t' box lid in a rectangular array for the pushbuttons (two widely separated for firin' and one for continuity test), a 1/8" hole for t' continuity test bulb, a 1/4" hole for t' toggle switch. Avast! Drill 2 more 1/4" holes one inch apart in t' side o' t' box for stress relieved launch wire anchor port.
2. Mount t' buttons and switches in t' proper holes per t' package instructions.
3. Cut pieces o' 22-gauge wire suitable for connectin' everythin' together, twist them together t' attach t' t' proper components, arrr, and solder everything except t' launch wire, which is attached last.
4. Usin' 5 min epoxy, arrr, glue t' 1.5V battery box in place. Aye aye! [Note: t' two 9V battery connectors must be left hanging--not glued--or t' batteries will be difficult t' attach and remove at will.]
5. Usin' duct tape, ya bilge rat, secure loose or danglin' wires t' t' box lid
6. Split t' launch wire (clear speaker wire) for 6" at both ends. On one end, solder t' 2 copper test alligator clips.
7. Feed t' other split end through and back around t' two holes in t' side of t' box (to act as a stress relief t' protect t' circuit in case somebody trips on t' launch wire) and solder t' ends in place per t' circuit diagram.
8. I used pieces o' electrical tape t' cover all t' solder joints.
9. Label as appropriate all t' buttons and switches. I left t' finished product unpainted.

Flight:
Before field testin' Back-Up Box out at t' launch site, I performed a static test in me back yard by tapin' a C6-7 t' a heavy metal post, riggin' it with an ignitor, and givin' it a shot. Avast, me proud beauty! Ya scallywag! I pressed down on t' continuity check button and t' dinky 25mA bulb lit up! Turned main power toggle on. Begad! I pressed down on left and right firin' buttons. Aye aye! Aye aye! Nothing! I tried again. Ahoy! Nothin' again!

Now what do I do? Then it occurred t' me that t' main power toggle switch might be wired in backwards and therefore be actually in t' "off" position. Blimey! (Don't they label these things? How is one t' know?). Blimey! Begad! I flicked the toggle t' other way, ya bilge rat, pressed t' twin firin' buttons again and WHOOOOOOSH! T' motor fired! I then relabeled t' main power switch. Hey, this electronics stuff isn't so hard. My test program for t' Back-Up Box consisted o' t' following, usin' different rockets:

• Estes D12-3, matey, ignited by Quest Tiger-Tail
• Aerotech E30-7, ignited by AeroTech Copperhead
• Estes D12-5, shiver me timbers, me hearties, ignited by Estes ignitor
• Aerotech F23-4 Econojet, shiver me timbers, ignited by Aerotech FirstFire Jr.
• Aerotech E30-4 ignited by AeroTech Copperhead
• Aerotech F50-6 ignited by Polecat Aerospace hand-dipped e-match
• Cesaroni G79SS ignited by Cesaroni e-match

In every case, t' motor fired t' first time with no failures. Continuity was checked every time with no inadvertent firings. Ya scallywag! Blimey! Over a period o' two launch days held two weeks apart, I invited others t' try Back-Up Box usin' the original set o' 9V batteries, arrr, again with no misfires. Ahoy! Blimey! After 20+ launches, arrr, arrr, the system is still operatin' as new, so t' battery capacity is 20+ launches per set o' 9V batteries. Begad! Blimey! I did try one more test: cluster firings with Back-Up Box. Usin' fresh batteries, matey, two motor clusters consistin' o' Estes D12s and usin' a clip whip were repeatedly launched with no trouble. Arrr! Blimey! Aye aye! Blimey! However, matey, when I tried a 3 motor cluster, only 2 motors lit. Avast, me proud beauty! Blimey! Arrr! Blimey! Repeatin' t' test gave t' same result. Back-Up Box has t' volts but nay t' amps so therefore cluster launches are limited t' 2 motor Estes clusters. Begad! Blimey! That seems t' be its only limitation.

Summary:
Back-Up Box is pretty idiot proof respectin' both construction and use in mid power rocketry. Ya scallywag! Begad! It is cheap, simple, safe, shiver me timbers, and perfect for first time junior electricians. Avast, me hearties, me proud beauty! It fully meets its design objective as a light, me bucko, reliable, convenient launch controller t' be carried in t' car at all times as a backup. As far as I know, it be t' only 18V launch system around. Ya scallywag! Ahoy! All t' components could be easily stuffed in a much smaller container by somebody who knows what he's doin' but I like t' larger 7x7" cigar box as it has plenty o' room inside for a spare set o' 9V batteries and a small Radio Shack battery tester. Plus it still has room inside for a couple o' nice, stinky Garcia-Vega Coronas to enjoy after t' launch. Blimey!

PROs: Small, ya bilge rat, inexpensive, matey, and easy t' build. Arrr! Powerful enough t' fire any single ignitor and safe for t' continuity check o' even low current e-matches. Simple, effective dual-button interlocked firin' that is childproof and unlikely t' be triggered by accident. Begad! Avast! A further layer o' safety can be added by unclippin' one o' t' 9V batteries when steppin' away from t' controller. Easy to troubleshoot circuit is easily accessible and as simple as it gets. Avast, me proud beauty! Avast, me proud beauty! Good for 20+ launches per battery set and you can buy fresh batteries for each launch for t' cost o' an Estes D12 motor. Begad!

CONs: Nay useable for HPR, me bucko, due t' short (38') launch cable. Arrr! Blimey! Batteries are not rechargeable so I recommend fresh batteries for each event. Begad! Aye aye! Blimey! Nay t' be used for clusters o' more than 2 motors. Avast! Ahoy! Blimey! Thin wooden case is nay particularly strong (but is rustproof and non-conducting!). Well, blow me down! Dinky 25mA continuity light is hard to read in direct or bright sunlight. Back-Up Box may get t' job done but it's a little funny looking, kind o' like Steve Buscemi in "Fargo".