DIY Scuba Tank (breath underwater)

I need some advice. I have a great idea that would be amazing if it worked. I want a small scuba/air tank whatever you want to call it (like a scuba secondary tank or a paintball co2 tank) that i can use to mess around with in a pool. I dont want to be constantly breathing, just enough to take a deep breath, go underwater and hold it for a minute, release air from the tank-take a breath, hold it, take another breath from the tank, hold it, and so on. Just enough to get a few breaths and be under water to last me for 5 or 10 minutes. The only thing is i dont want to have to fill it at a dive shop or from a tank that has to be filled at a dive shop like scuba secondary tanks. i want to rig it to fit a bike pump (which probably will not have enough psi to get the amount of air i want) or my air compressor. So i would like advice and also would i need an air regulator since im not constantly breathing? what could i use as a regulator if i need one at all? 

tank if you do make this DO NOT USE AN AIR COMPRESSOR it will put oil and dust in the air tank