Electric Pyrotechnic launch controller

[jhonen]

Hi, I'm looking for some help in making an electric launch control system for my fireworks. They are taking up waaaay too much time to launch by hand. I figured out the basics of the table, just hooking up around 90 speaker terminals, getting one model rocket engine ignitor per firework fuse. Then using a low current ( a cordeless drill battery works great) light the fuses. The thing I'm having problems with is the controlling device. I would prefer not to use 90 different switches but would love to have as much control over firing order as possbile. I also havent quite figured out how much power I'm going to need. Any help with this would be greatly appreciated. Thanks!!!!! :twisted:

 

[bogdanfirst]

instead of switches you could use relays or transistors. you just have to figure out the current. if you have a low current than you could use a transistor. for a highter current you will need a realy.
do you just want them to light up in order?
you could make a circuit that will do this.

 

[jhonen]

No I would like to have the ability to fire them in any order I choose or if it turns out to be way easier then the order isn't as important as the timing

 

[jbeng]

You could use a switch matrix something like this. Where the lines cross in the matrix, connect an ignitor. To control 100 ignitors, you'll need 20 switches. To fire an ignitor, press the appropriate row and column switches at the same time (ie. To fire ignitor A1, press switches A and 1, etc.). I would probably add a key switch at the top between +V and the column switch bus for safety, and keep the key in YOUR pocket when you're out working on the firing line near the pyro stuff.

Edit: After looking at this a bit closer, you should add a diode for each ignitor to prevent "sneak" currents from possibly setting off other ignitors unintentionally. The diode should be able to safely handle the current which will flow thru an ignitor. I have updated the graphic to show this detail and have used a lamp to represent the ignitor. jb

 

[jhonen]

Thats Great, Thank you so much for your help. One more quick question. Does anybody have any good places to get project enclosures from? Thanks

 

[jbeng]

You should be able to get 'em from Mouser Electronics, Allied Electronics or Newark Electronics. Metal, plastic, cheap, expensive, whatever, you can probably find whatever style you want! (Mouser's probably least expensive...)