relay question

[cynic]

A while back I posted to get some help on a circuit - A picture of the circuit I ended up with is here -
**broken link removed**

A problem I have with this circuit is that for some reason, when I initially plug in the power I get a little jolt of power that throws my relays. This is not related to anything on the bootup of the gumstix as it occurs immediately when power is applied, not during the boot process when probing of GPIO ports might occur.

Is there something I can do with the circuit to prevent this? Could someone help me understand why it occurs? It seems to be related to the gumstix computer.

Thanks!

EDIT ---

One more question. I was using a 9V battery to light a rocket igniter. It seems a capacitor might be a better option as I really need a short burst of lots of power.

Would something like this do the trick?

http://www.sparkfun.com/commerce/product_info.php?products_id=8982

 

[Sceadwian]

You need to learn to draw proper schematics, my mind balks at trying to sort out what you posted though I think other users here might be able to decipher it a bit better.

Weather or not a capacitor discharing would work depends on a lot of things, through a relay probably not such a good idea as they don't like high currents, you'd be better off using osmething like an SCR instead which are often used for pulse discharges. That aside you need to determin the exact energy delivered to the electric match that will cause it to ignite, determine the entire serires resistance of all the wire involved and calculate out what kind of current pulse you'lll get if you dishcharge it. There's really a bit of real work to be done if you want to be able to use this reliably.

What is the optoisolator module you're using?

 

[cynic]

This is the optoisolator - SparkFun Electronics - Opto-isolator Breakout

The required energy for an electric match is not exact; I know a 9 volt battery will do it in 2 seconds or less.

I would guess 7 watts would do it. The circuit I showed will do it, It would be nice to have something lighter than the 9V battery. Perhaps I'll just solder 3 watch batteries in series.

Any idea on the relay activation on power up?

I should probably take a basic electronics class as well