How to Make a Box in One Hour or Less

Project Briefing
Description::The goal of The Box is to achieve electrical ignition of fireworks with the intent of remotely controlling our annual forth of July spectacular, Thunder over Flags Fork. We aim to use the basic principle that, if you pass too much current through a very fine wire, its resistance will be too high to conduct the load and the excess energy will be converted into heat. We didn't want to buy nichrome wire and make fancy igniters dipped in lacquer so we used a single 6" strand of copper wire taken from 22 gauge stranded wire. In theory, after coiling nearly the entire length around a piece of visco fuse and short circuiting the wire with a car battery, the copper wire should glow orange and melt thus igniting the fuse.  This would be neat enough but, as the Knights of the Rumfish know, its all about a little something called the coolness factor.  Our ultimate desire was to wire up every firework on the field before the show and control them all from one control panel 100ft. away from the launch platforms.  Zerm the Rumfishian Empire's top electrical engineer, devised an incredible device.  It would end up being a dual four bit binary system capable of addressing 30 seperate ignition points and it would come to be known as "The Box."

The Team
"First I would like to thank everyone who participated to make, not only this project, but all of Thunder over Flags Fork a success. I would like to exclusively thank everyone who worked on the fireworks or at least dontated money because, Rumfish permitting, no one of us could have done it alone.  It was incredible to see all of us working together to make this plan a reality and I have never been so proud of us.  So, thank you all for your time, effort, and overall enthusiasm.  I can only hope that we could conjure such spirit on our next big project.  The following is a list of people I saw helping specifically on the fireworks.  If you helped but your name is not here, then please leave your name and a description of your contribution so that you may be recognized."

- Zerm

Techimo

 * The main monetary contributer to the entire Thunder over Flags Fork event, Techimo payed what will only be described here as way too much.
 * Expertly selected, payed for, and handled most of the fireworks.
 * Concieved, built, and loaded our two mortar racks.
 * Served as a general pyrotechnics and saftey expert.
 * Performed extensive research which contributed signifigantly to the planning of the system.
 * Tagged his girlfriend along for the ride and made her house the central storage facility for everything explosive. (For over 2 months)

Nova

 * Contributed to the fireworks stockpile.
 * Hand made all the yellow ignition cables (a lot of damn cables).
 * Performed extensive soldering.
 * Lent a hand for all construction and testing.
 * Documented the project developement.

Nutz

 * Helped immensely with construction including design and construction of the two launch platforms and the actual Box.
 * Contributed monetarily to the ignition system.
 * Hand made all the white cables.
 * Performed some extra soldering.
 * Main system operator for The Box at show time.

Lord Gnarky

 * Contributed to the stock pile.
 * Helped handle the fireworks.
 * Focused on group coordination and cohesion.

Swiss Maiden

 * Cataloged the entire stockpile with MiniMuffin.
 * Painted The Box.
 * Made igniter coils.
 * Provided comic relief.

MiniMuffin

 * Helped catalog the stock pile with Swiss Maden.
 * Helped pair the yellow ignition cables
 * Made igniter coils.

Death From Toasters

 * Got injured by a spool of wire while helping Zerm

Mongo (The Paul)

 * Provided valuable electronics insight.
 * Built both relay blocks.

Zerm's Dad

 * Provided valuable construction advise.
 * Generally oversaw construction of platforms, racks, and box.
 * Granted full use of his shop and resources.

Zerm's Mom

 * Contributed to the stockpile.
 * Made igniter coils.
 * Supported the team (preparing food and tolerating the horrendous mess in her kitchen).

Zerm

 * Electronics expert designing and building most of the electrical system.
 * Contributed monetarily to the stockpile and ignition system.
 * General overseer to the project guiding construction and dividing tasks.

Delusionalpickle

 * Sat in myrtle beach.
 * Hoped no one would die (it worked).

Electric Ignition
This was a problem we had been working on for a couple of years. We wanted the control of an electric ignition system but didn't want to buy blast caps. We wanted a reusable electric system. The original idea was to create an electric spark gap which would generate a spark powerful enough to ignite near by combustible material; namely black powder. After a lot of research into high voltage circuitry and chemical reactions, this method was deemed unfeasible and the project was slowly pushed to the back burner.

About a year later, we were all sitting around talking about camping or something when Nova mentioned something about starting a campfire with a 9V battery and a tuft of steel wool. Short circuiting 9V through the tiny fibers of the steel wool caused them to spark and burn, igniting tinder for the fire. The idea revolutionized my whole approach. We were so frustrated that he had never mentioned the idea within the context of electric ignition but still so thankful that he mentioned it at all. We soon purchased some steel wool and began to experiment. Though the steel wool would not be reusable, it was so negligibly cheap that it didn't matter. It wasn't until later that we acquired a lead acid battery, a storage capacitor, and the heavy duty switches and clips required to build a prototype system. Zerm made a simple circuit to charge the capacitor from the battery and then dump the charge through a tuft of steel wool which was lightly wrapped about a fuse. The first test fire of a bottle rocket worked flawlessly.

Though this method worked, it was crude and had the tendency to be unreliable. With the thick visco fuse we were going to use in the show, we would require a method which could deliver more heating power. Searching the internet, we found a guy who passed electric current through a spring which heated up and ignited the fuse of a bottle rocket. This was the kind of solution we needed but buying the number of springs required would be counter productive toward our goal. We needed an even more efficient solution. Wrapping the fuse in nichrome wire could work too but this was also a special component that would need to be ordered and cost more than it was worth. Finally, we found the solution. We took lengths of stranded copper wire, removed the strands, and wound them tightly about the fuse. This was a cheap and readily available solution that worked beautifully. The small diameter of the copper strand creates a high resistance to massive electrical currents such as that of a lead acid battery. Being a highly conductive metal though, it readily dissipates the excess current as heat causing the wire to glow bright orange and then melt. The molten copper reliably ignites even visco fuse without any chemicals, flame sources, or caps required.

Launch Platforms
The two impressive platforms were 4'x4' and made from 1/4" plywood and 2x4's. Each platform was built to support Nutz and Zerm's weight even when Nutz jumps up and down on them.  The idea was to provide a level launch surface while covering delicate circuitry from fire and fallout.  Nutz performed most of the construction and they functioned flawlessly.



Mortar Rack
The mortar rack designed and constructed by Techimo and Zerm for Thunder Over Flags Fork 2006 can fire 20 2" diameter mortar shells. It features robust, high density poly-ethylene (HDPE) tubes which are resiliant to heat, pressure, and corrosion.  Unlike PVC, HDPE is not brittle and will not shatter if it is broken.  In case of a misfire, it is much safer to use the HDPE tubes as they will not shraptnel if ruptured.  Crossbars at the top and bottom of the rack keep the tubes stable during firing.  The thick square base and cubic proportions provide excellent stability.  The rack's plywood structure is easy to staple igniters or fuse to.  Finally, handles were mounted on the sides for easy transportation.  Flexible and robust, it is the best rack in our arsenal.

Electronic Design
Engineered by Zerm The Box runs on 12VDC and features two 15 line channels which are addressed in four bit binary manually from the control panel. The two four bit channels run parallel via a CAT5e cable to the two receiver modules 100ft. down field.

Power for The Box is provided from a standard 12V lead-acid car battery which is attached via jumper cables to the large bolts protruding from the back of the control panel. +12V, debt, and GND are carried via a 100ft. grounded extension cord from the control panel to the two modules. Each module has a 5V regulator to power the decoding circuitry.

Each module contains a 16 line multiplexer (74152 TTL) chip which decodes the four bit signal into one of 16 outputs. Two transistors on each output line invert and amplify the signal to drive 12V relays. These relays act as switches which close a specific ignition line to the main debt line coming from control panel.

Once a line is selected and a relay is closed, the user must pull the safety switch to arm the device. Once pulled, the control panel sends a small current through the debt line to test for a complete circuit. This current sinks to the base of a transistor which drives the "Armed" LED indicator so that the user is warned to expect an ignition if the red "GO" button is pressed. The user now has only to push and hold the GO button to short the main power to the debt line pumping massive current through the selected ignition line to burn the igniter.



Building a Box
The Box itself was a feat of ingiuity and the result of the combined effort of Zerm, Nutz, and Swiss Maden. First, a thick and rigid wooden box was constructed as a frame. The idea was to mount the controls on the lid and be able to open the hinged box to work on the insides. Large bolts in the back connect to an external battery. In parallel with this is a storage capacitor to act as a buffer for the power source. Power and the two four bit channels feed outward via CAT5e and extension cord. The Box features "Power" and "Armed" indicator lights including illumination of the eight channel control switches. Caution stripes were then painted on the face to make it look intimidating!

Hooking It All Up
Pulling everything together was a massive task that took an entire day. Hundreds of feet of wire and cable connecting the control panel, two modules, and thirty igniters were connected by screw terminals at various points throughout the system. We tediously stripped wire and secured all the screws over many hours. Then came the test and, of course, we had hooked up module A in reverse order such that line 1 was line 15, line 2 was line 14, and so on. The blazing heat and humidity did not help us as we toiled away.

In the end, we were left with a hideous knot of tangled wire and electronics which we piled into boxes and slid under each platform. It was crude and ugly but, more importantly, it worked.

The Results
Days of blood, sweat, and tears were all worth it when the first firework was ignited at the push of a button. We had contructed a 30 point firework ignition system. It is a device that will continuously contribute to the betterment of the Thunder Over Flag's Fork event.

Project Reflection
Though the project was considered a success, it is far from finished. In fact, the device used at Thunder Over Flag's Fork 2006 could really only be considered a crude prototype which undoubtedly has room for improvement.

Failure Points
Our biggest problems likely stemmed from poor construction. At crunch time, over sights were made and corners were cut. This resulted in crude and ineffective designs. Notably:
 * Several ingniters failed to fire on platform B. There are a couple of possible reasons:
 * Connections were improperly made or were jarred loose.
 * The "Debt Bus" which sank all the ingniters broke as it was prone to.
 * Inefficiencies throughout the entire system were such that not enough power could get through to cause proper ignition.

Design Efficiency
Efficiency of our current design is absolutely unacceptable. There are many factors contributing:
 * Significant power loss over the system caused the battery to drain quickly and for igniters to take unpredictably long to heat up.
 * The amount of cables run was excessive. More cable means more setup time and more possible points of failure.  This ought to be improved.

Design Improvement
Any improvements should focus on practically and cost effectively transforming our current prototype in to a finished and functional device for Thunder Over Flag's Fork 2007.
 * Efficiency Fixes:
 * Tin all leads to insure protection of copper and solid electrical contact at terminals
 * Relocate Battery to down range so as to not cause power loss over a long debt line.
 * Redo/Remove Debt Bus so that it does not suck.
 * Make real connections where jumper clips were used.
 * Sauter all alligator clips to their ignition cable.
 * Use 1/4" Mono Jack in place of screw terminals for ignition lines so that they are easy to connect and electrically secure.
 * Use a different igniter such as nichrome or graphite that will make better use of power.
 * Enclose all electronics so that they do not flop about and become disconnected.
 * Use CAT5 Jack for channel line connection to reduce setup time.

Power
Considerations
 * Relocate main batteries to the platform end in order to improve power transfer and simplify overall design.
 * Extensive testing needs to be done on current mode of power connection to find a better alternative.
 * Auxillary batteries specifically for The Box (9V perhaps) would eliminated the neccessity of power transfer across the field and would be essential for a wireless solution.

Communication
Considerations
 * Current non serial protocall is simplistic in design but tedious and feable in implimentation.
 * Serial communication offers more data and flexibility over less wires.
 * RS232 is a standardized protocall readily available on microcontrollers, proven to go great distances at lower baud rates, and can readily interface with a computer.
 * Wireless is certainly the most elegant but has its own problems such as cost, interference, and lack of wireless experience on our part.
 * Cheap "black box" wireless remote control modules are commercially available for a price so we would not have to build it.
 * Price of cable could offset the savings with a wired solution.
 * Some kind of bus would be better than RS232 for addressing multiple modules.

UI ("The Box")
Considerations
 * 16 position rotary switches could easily address the platforms without the need of digital circuitry.
 * With a microcontroller in The Box, LCDs and keypads are possible.
 * LCD's would be monocolor character displays with backlight.
 * It may be difficult to read LCD's in daylight.
 * Could all essential data be displayed in a numeric LED package?
 * Keypad and display make for simple and flexible UI and has incredible Coolness Factor.
 * Illuminated displays will make operations easier in the dark.

Igniters
Considerations
 * NiChrome wire has much better power to heat conversion meaning more heat faster and at higher efficiency.
 * NiChrome wire burns up too quickly.
 * Testing will need to be done to find the best guage of wire to use.
 * Incredible thick wire could possibly be used to make a permanent heating element which is resuable.
 * Graphite is highly effective as testing has proven.
 * Graphite is tedious to work with.

Ignition Drive
Considerations
 * Use a solidstate (SCR or MOSFET) solution to drive igniters as opposed to electromechanical (relays).
 * Solidstate is much more energy efficient and interfaces more readily with control circuitry.
 * Relays are easy to use and we have already done them once.
 * Some power solidstate devices may be more expensive than relays to achieve our purpose.

Internal Control
Considerations
 * A full microcontroller will give us more control and flexibility.
 * A microcontroller will require more code work.
 * A microcontroller will be required for serial and or wireless communication.

Misc. Redesign
Considerations
 * We have the capability to get printed circuit boards.
 * PCBs are expensive.
 * PCBs mean more design work but less assembly work.
 * PCBs would mean a more efficient, proffessional, and structually integral design.