We are currently in development of this product, we've gone through a few design iterations so far. For instance, the 9" long minature tank had to move to a horizontal mount on a belt at the small of the divers back in order to get pressure readings. Our first thought was that when a diver ran out of compressed air that they would still be able to breathe what was in the system while they gradually assended, but some divers are wanting to take this down to deco levels. I'm still not sure about that idea, I wouldn't want my equipment that far away from me if I were doing a decompression dive unless it were mounted to the dive boat. The target audience are really divers down to about the 60' range for non-deco periods.
Moving the minature tank to dive level also improves safety since your compressed air is on hand, and it allows standard compressed air connections to BC, our original surface mounted tank required manual inflation of a BC.
The pump itself is really pretty simple (KISS), exhaled compressed air is driven into one side of a diaphram pump, compressing fresh air is pumped out the other side. The only real trick is to make it alternate. Our original prototype for that was entirly mechanical, but making that an electronicly switched system will improve efficiency and also make breathing easier.
Right now we are looking at a phased release, a shallow water unit without the compressed air system will be first, allowing divers to explore shallow reefs for several minutes at a time. Following that will be the full blown deep water unit. We hope to get the shallow water unit to ship in mid summer.
Thanks for the interest, please let me know if you have any other questions.
