Brief:
T' Back-Up Box is a simple, arrr, low-cost launch controller anyone can build. I built it as part o' a NARTREK Advanced project. Arrr! It can fire any kind o' igniter and is entirely self-contained, matey, ya bilge rat, operatin' on 18V instead o' t' usual 12V. Well, blow me down! It is lightweight, matey, compact, me hearties, 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, shiver me timbers, 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. Arrr! 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, me bucko, me bucko, or unused and unfinished at craft stores like Michael's for $1.98. Avast, me proud beauty! Ahoy! Power comes from two 9V batteries wired in series and will easily fire Copperheads, First-Fire Jr., or e-matches as well as Estes and Quest igniters. Ya scallywag! Ahoy! 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). Avast! 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. This is a common industrial safety procedure. Begad! Begad! It is therefore self-enabling, me bucko, self-arming, and self-safeing. Arrr! Avast! 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. Arrr! Although suitable for mid power, thar be no removable launch key, me hearties, thus it does nay strictly meet t' NARRRRR code specification for a high power launcher. Ahoy! (Although technically, arrr, 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). Ya scallywag! Avast, me proud beauty! T' bottom line: two separate things have to happen t' complete t' Back-Up Box firin' circuit, shiver me timbers, me bucko, so it is safety interlocked as t' Model Rocketry Safety Code required. Avast, me proud beauty! Begad! It is also childproof: kids won't figure this out unless you show them. Begad! Ahoy!

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

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

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

T' utter simplicity o' Back-Up Box is evident from t' attached circuit diagram. Begad! Ya scallywag! Blimey! [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), me bucko, a 1/8" hole for t' continuity test bulb, a 1/4" hole for t' toggle switch. Blimey! Blimey! Begad! Blimey! 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, matey, and solder everything except t' launch wire, ya bilge rat, which is attached last.
4. Usin' 5 min epoxy, me hearties, glue t' 1.5V battery box in place. Ahoy! Blimey! [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, secure loose or danglin' wires t' t' box lid
6. Split t' launch wire (clear speaker wire) for 6" at both ends. Aye aye! Ahoy! On one end, ya bilge rat, 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. Begad! Blimey! I left t' finished product unpainted.

Flight:
Before field testin' Back-Up Box out at t' launch site, ya bilge rat, I performed a static test in me back yard by tapin' a C6-7 t' a heavy metal post, me bucko, riggin' it with an ignitor, and givin' it a shot. Begad! Blimey! Ya scallywag! Blimey! Blimey! Blimey! I pressed down on t' continuity check button and t' dinky 25mA bulb lit up! Blimey! Blimey! Blimey! Turned main power toggle on. I pressed down on left and right firin' buttons. Nothing! Blimey! Blimey! Blimey! I tried again. Avast! Blimey! Blimey! Blimey! 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 was actually in t' "off" position. Ya scallywag! (Don't they label these things? How is one t' know?). I flicked the toggle t' other way, 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. Aye aye! Well, blow me down! My test program for t' Back-Up Box consisted o' t' following, usin' different rockets:

• Estes D12-3, ignited by Quest Tiger-Tail
• Aerotech E30-7, ignited by AeroTech Copperhead
• Estes D12-5, ignited by Estes ignitor
• Aerotech F23-4 Econojet, 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, shiver me timbers, t' motor fired t' first time with no failures. Well, blow me down! Well, blow me down! Continuity was checked every time with no inadvertent firings. 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, again with no misfires. After 20+ launches, the system is still operatin' as new, me bucko, so t' battery capacity is 20+ launches per set o' 9V batteries. I did try one more test: cluster firings with Back-Up Box. Usin' fresh batteries, two motor clusters consistin' o' Estes D12s and usin' a clip whip were repeatedly launched with no trouble. Aye aye! Well, blow me down! However, when I tried a 3 motor cluster, matey, me hearties, only 2 motors lit. Begad! Ya scallywag! 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. Avast, me proud beauty! That seems t' be its only limitation.

Summary:
Back-Up Box is pretty idiot proof respectin' both construction and use in mid power rocketry. Ahoy! It is cheap, simple, matey, shiver me timbers, safe, and perfect for first time junior electricians. Begad! It fully meets its design objective as a light, reliable, convenient launch controller t' be carried in t' car at all times as a backup. As far as I know, arrr, matey, it be t' only 18V launch system around. Blimey! Blimey! 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. Arrr!

PROs: Small, arrr, me bucko, inexpensive, 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, me hearties, ya bilge rat, effective dual-button interlocked firin' that is childproof and unlikely t' be triggered by accident. Well, blow me down! 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. Blimey! Good for 20+ launches per battery set and you can buy fresh batteries for each launch for t' cost o' an Estes D12 motor. Ahoy!

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