hello i am planing on making an air gun, but Im a little confused. my first question is that what is the best type of sprinkler valve to use (brand and size)? my barrel is 1/2" and air chamber is 1'. My second question is do they make a battery operated sprinkler valve, so i can just hook a electronic switch to it? if so what brand? my third is why is the blow gun valve necessary? thank you those who post answers.