It seems like making your own scuba equipment is a challenge that more people are taking.
This individual challenged himself to make a scuba diving helmet. He has plans for over a year to do it and he finally got around to completing it.
He basically uses a plastic water bottle connected to a garden hose air supply. The theory is that when the air supply is pumped into the bottle it displaced the heavier c02 allowing him to breath the freshly pumped air. By the way, a bicycle pump is used by an associate to pump the air.
Although, his invention and idea is rather crude…I give him a lot of credit for having what looks like a well prepared team including at least 1 scuba diver for backup support.
Watch him put this contraption of a scuba diver helmet to the test in the video on the next page below.
Watch how to make a home made scuba breathing device [Video]