UPDATE: A 9V battery would not ignite my rocket igniter! (I learned this after dragging my kids to the park to try it lol). I don't think it can supply enough current (too much internal resistance). So this may be useless :O

This is a handheld trigger button for model rockets. A 9-volt battery fits inside and can be wired to a small push switch (12mm square). The top is friction fit to the body.

Wire can then be spooled out to the rocket launch pad and connected to the ignitor.

I have not tested this yet, but it appears that the engine ignitors require around 2 amps (at a fairly low voltage), which a 9V battery should be able to easily exceed for the few seconds necessary. I used thick speaker wire so as not to cause much voltage drop between trigger and rocket.