... the iPod/ iPhone doesn't have any pressure sensors, so you would need a sensor for depth (and tank pressure, if it was AI) and a processor and circuitry to convert the signal into something that could be transmitted to the iPod. We considered doing something like this years ago with the Palm, but rejected the idea after looking at the tradeoffs vs. a dedicated unit. One concern would be battery life- I use my iPhone as a timer/ GPS for rowing, and after running the display for an hour it is at least 40% depleted.
Some of the algorithm comments (on another site related to this same product, where they indicate that the accuracy of an algorithm is related to the number of tissue groups, and suggest they could use up to 256) leave me doing a bit of head scratching.
There are a number of issues in using something like the iPhone for a processor/ display unit. They are all solvable at some level, but there is a point of diminishing returns, where a dedicated device starts looking like a better answer- particularly in a difficult environment like underwater. And there is a lot more to a functional dive computer than the obvious basics- a big part of the interface is working out how you handle unexpected events, when the diver does the "wrong" thing.
Just off the top of my head:
- Battery life and/ or charging in the case would need to be resolved to a satisfactory level.
- Interacting with the computer when it is in the case (no touchscreen function, and accelerometer sensing has some quirks, though it can be done) would need to be really well thought out.
- You still need a microprocessor, software and circuitry (essentially a small dive computer with no display) to get the sensor signals converted to something the iPhone can handle.
- You're hoping that the form factor doesn't change too rapidly, as you are hitching yourself to a big company's plans (probably not a huge concern with the iPod/ iPhone, since there are already so many).
On the plus side:
- iPhone has plenty of processing horsepower and a nice, big screen
- The iOS development tools make creating a user interface (or a snazzy looking demo) a very easy task, compared to developing a dedicated unit.
- There are a lot of iPhone/ iPods out in the world. Done right, and not over hyped, it might be a path to a relatively low cost color computer. You would have to make all the parts really inexpensive for it to work out, though.
For each of the last couple of years there has been some sort of iPhone in a box solution shown as a dive computer. So far as I know none of them have yet become shipping products. There is no reason it couldn't be done, but it may be less ideal than it seems at first glance. Done right, though, it could have potential.
