Design Challenge : The Amateur Fireworks Show

I saw/heard drum riffs being played on salutes (large firecrackers) as a demonstration of some comany's electronic firing system once.  They finished with an encore of "Shave and a haircut."  It was very impressive.

A problem is that while bottle rockets are cheap, most electrical ignitors run about $0.50 each...

There is probably a better way, but just a thought...  Regarding the electronic ignitors being $0.50each (and only one-time usage!!), how about buying a spool of Nichrome wire?  After cutting into very small sections and crimping the small Nichrome section in the middle of two lengths of "regular wire", it seems that you would have a very low-cost (possibly re-usable) fuse lighter.  It is fairly easy to get the Nichrome wire to be "red hot" on command with a little bit of ohms law design work.

Respectfully,

Interesting, the hurdle of lighting each fuse is the real challenge. 

I was considering a spark plug like, arcing elements. Like how the cordless soldering irons work.

Something else to consider, how can you control say 100 rockets? How can just one in particular be triggered? Multiplexing like a LED display might be the best option.

Cabe

Hi,

I like the idea of the Nichrome wire. I used bycicle headlights (6V/50mA) in the past to set of my explosions. You just crack the glass and insert the rockets ignition cord. It is also a 'one shot' option. If you use a traditional Christmas tree light you have lots of igniters. Bye the way, using words as 'igniters' and 'explosions' in our discussions; could this result in an investigation by some government agency? :-)

Lot's of success (or good luck)

Best regards, Enrico Migchels

Enrico,

I was thinking the same thing.

But, I have a suggestion that could replace the Nichrome wire. Using small springs tied at either end by larger gauge wire. Then the spring almost acts like a light bulb filament.

But more importantly, I want to know how to control a large matrix of transistors with only a few Gen IO pins from a uC. Ex: 100 transistors and 10 IO pins, for example. Any thoughts?

Cabe

Hi Cabe,

You can control as many as transistors just 3 Mcu IO's using 74HC595 shift registers or equalevant chips having same function. If you give me more details about your design, i can make the schematics for you.

If you decide to use 74HC595 then you need 13 chips. According to the use of the transistors ( sink or source ) and the power requirements you may need extra components.

Firat

Cabe,

Igniting your rockets this way will result in more or less severe timing differences.

You can consider to group your rockets, say 5 or 10 per ignition instant. The group of rockets will go off with a nice whooooshhh (I imagine).

Success !!!

Klaus

I was looking at building a Christmas display at one point controlled by a computer. You know the displays that go with the music. Something like that might work for you as well.Ths is set up for 120VAC because it was meant for lights but I know I saw an LED board set up as a working model of one of these circuits some where.

Here is a link that I came accross if you look around there site they have a program on there to.

http://discolitez.com/pmwiki/pmwiki.php?n=hardware.deluxe32

I was looking at building a Christmas display at one point controlled by a computer. You know the displays that go with the music. Something like that might work for you as well.Ths is set up for 120VAC because it was meant for lights but I know I saw an LED board set up as a working model of one of these circuits some where.

Here is a link that I came accross if you look around there site they have a program on there to.

http://discolitez.com/pmwiki/pmwiki.php?n=hardware.deluxe32