No air integration in high-end and tech DCs . Why ?

[eelnoraa]

..... I've seen fairly new rec. divers ask about what computer to buy, and the Petrel suggested on the grounds it's a great computer and you can 'grow into it' if you ever go tec. Some of us then say 'AI is nice and the Petrel can't do that.' And off we go, given that only a small minority of rec. divers ever go into tec. diving (wonder what %?). And the recent inclusion of a recreational mode in the Petrel, if I recall correctly, would suggest that Shearwater is aware their product could appeal to a broader market (rec. + tec., not just tec.).

I think the key is "fairly new rec diver". I don't think a seasoned tec diving will choose a computer based on AI feature. More than a few people I know, started with some kind of AI. As experience accumulated, slowly ditching AI.

The beauty about keeping track of consumption in our brain is that if your SAC change in a dive, you will notice it and make necessary adjustment, making a dive safer. A data logging for post dive analysis is after the fact

 

[Centrals]

It was NOT available when I first started diving in mid 90 and then tec(98). I am more than happy with the spg so why bother with something more expensive.
High-end means more expensive but NOT necessary better and reliable.

 

[AFdivedoc]

I think the key is "fairly new rec diver". I don't think a seasoned tec diving will choose a computer based on AI feature. More than a few people I know, started with some kind of AI. As experience accumulated, slowly ditching AI.

The beauty about keeping track of consumption in our brain is that if your SAC change in a dive, you will notice it and make necessary adjustment, making a dive safer. A data logging for post dive analysis is after the fact

I'm sure in another 20 years, divers will wonder how guys back then ever got along with that old analog stuff. We're just not there yet. As one who learned slide rules, analog E6B navigation computers, and felt right at home with THE WHEEL, I have to say they are still perfectly viable, and crank out perfectly good results for those who still choose to use them. No batteries required! Then again, I rarely choose to use them myself these days. I do always use an analog SPG, and eschew AI computer features. I'm not a hater--I have friends who do use these computers and are happy with them. I just find they are unnecessary and don't add to the quality or safety of my diving.

While I like some aspects of computer logging, and do go back and look at some dives for decompression profiles, etc, I really don't need a blow by blow, breath by breath breakdown. I already know I use more gas fighting current, or when I'm cold. I've planned for this by calculating SAC rates beforehand, going conservative and using these to calculate my reserve. Real time SAC rates from an AI computer are not that useful, to my thinking.

 

[markmantei]

I am really interested on how this can be done. If based on change in tank pressure, there are too many corner cases to distract the computer. Temperature change can change pressure? How about a free flow 2nd stage? How about sharing gas? Or passing a deco bottle to a team mate?? I don't see how a computer can reliably automatically figure out which stage a diver is breathing on.

If data logging is the sole purpose, how about pressure sensor and logger in SPG only. NO wireless AI connection to a wrist computer. Each tank must have its own SPG anyway, if each SPG can sense and log pressure reading, then it all it needs to do. With no wireless transmission, a smaller battery will be sufficient fitting inside the SPG. A few MB of memory take no space at all. There will be way more detail to this tho. Still how much more will such a smart SPG cost, and I wonder how many would care about logging tank pressure to begin with.

Or even better if data logging is the only purpose, how about a slate and pencil, or wetnotes. Way less cost and no need to re-invent the classic SPG

 

[eelnoraa]

Or even better if data logging is the only purpose, how about a slate and pencil, or wetnotes. Way less cost and no need to re-invent the classic SPG

Aren't we doing "think out of the box" brain exercises here??

 

[fnog]

I am really interested on how this can be done. If based on change in tank pressure, there are too many corner cases to distract the computer. Temperature change can change pressure?
How about a free flow 2nd stage?
How about sharing gas?
Or passing a deco bottle to a team mate??
I don't see how a computer can reliably automatically figure out which stage a diver is breathing on.

If data logging is the sole purpose, how about pressure sensor and logger in SPG only. NO wireless AI connection to a wrist computer. Each tank must have its own SPG anyway, if each SPG can sense and log pressure reading, then it all it needs to do. With no wireless transmission, a smaller battery will be sufficient fitting inside the SPG. A few MB of memory take no space at all. There will be way more detail to this tho. Still how much more will such a smart SPG cost, and I wonder how many would care about logging tank pressure to begin with.

Temperature changes can be compensated with the perfect gases law, or better model if needed, to obtain the actual moles/s or l/s flow out of 1st stage. (Or is there also no temperature sensors on those tec DCs ? )

Freeflow is a totally different pattern from breathing. Whether it happens on the active tank or another, I do not see why this would be confused with a switch.

Sharing gas will log consumption rates that are for 2 ppl, but it will not affect your switching time ( or deco calculations) as long as your mate stops using your gas before you switch. If you let someone use your deco bottle before you have switched, then you are still breathing on the last active tank, no switch detected either.

I have put no thoughts into how to do detect a switch correctly, or how gracefully the example criterion I gave above fails in corner cases. Remember, I am only putting out the question and some ideas for debate, I am not developping anything. The best would be to identify this prototype that was field tested a few years back and ask the questions to these guys; wether they were uwatec or other. In the end it is quite possible, like Dr L. suggests, that you have to confirm switches with button pushes on the DC. Or even that you must build in a messy "you missed a switch I made 2mn ago, I declare it now" feature into the DC. We are still talking about deco calculations which are needed only as backup because you have the tables for your plan printed and taped to your arm, right ? (How does a clear taped paper on arm slate ever fail BTW?)

The offline SPG with recording is simpler tan the one with data xmit. It could be downloaded by NFC in air, and from a powerful source that could also recharge its battery. But there would still be the problem of having a potentially leaky/shorted battery in there with risks to the mechanics of the SPG. And it is probably not so convenient to bring all your regs to the PC.

 

[DevonDiver]

I just find they are unnecessary and don't add to the quality or safety of my diving.

Like buying a GPS to use only when driving around your home-town that you know like the back of your hand.

What some seem to not grasp... AI, like GPS, is only beneficial to those who need it. A technical diver simply doesn't need that gas information. Technical training provides the ability to manage gas in a predictable and accurate way. Those gas management protocols can't be eschewed because they are critical and integral to the complex planning that must be carried out for a dive - so using AI achieves no real benefit.

A recreational diver might appreciate great value in AI. Just like using GPS in an unfamiliar city.

But the technical diver sees no value in it. If they didn't know what they're doing, they wouldn't be technical diving...

 

[Phil_C]

No computer I know gives you a continuous graph of what your gas was that you can overlay on the dive profile (maybe there are some that do, but I don't know of any).

Just to correct this TSandM, many computers will - both my Cobalt and D9tx take a pressure snapshot every 30 seconds (user configurable) and in the computer software can lay this over the dive profile, giving real time pressure usage data. I can even see a usage spike if I have filled a DSMB or had a free flow and can see real time consumption rates for each point in the dive. Having said that my D9tx "used" to give me that - the AI transmitter has failed, or at least we think it is the transmitter not the computer, but we do not know (LDS Suunto technician has looked at it, changed batteries, reset it etc. without luck - needs to go back to Suunto now, but I can't be bothered as I have lost faith in it).

I still use the Cobalt when I dive back mounted tanks but although that is AI it is not wireless, it is on an HP hose. Although I am only just starting to get into technical diving I have already started to gravitate towards brass and glass and use a Shearwater. The D9tx hasn't been dove in anything other than gauge mode for some months now. - P

 

[lv2dive]

I have been reading this thread and trying to give original premise modicum of respect but at this point I think I've reached my limit.

The issue with temperature is that some people breathe more gas when they are cold. This not some kind of temperature -related physics law that needs to be accounted for, via a dive computer algorithm.

I am going to bring up two topics that have already been discussed but hopefully add a Little additional insight. I sometimes dive with multiple stage and deco bottles. After I charge a bottle, it is not out of the ordinary for a bottle to slowly or suddenly loses it's charge. Would the computer assume that I was breathing the bottle if it was a slow loss of gas? what would the computer think when I recharged it? Of course that COULD be accounted for but that is one of the things that I think people are trying to explain... This is just more complicated than it may appear to a rec diver.

And of all the other things that I could mention… I will focus on only one. If I am doing a two-stage dive with 2 deco gases I would need five doohickeys to send information to the dive computer. I'm pretty sure that in any world those doohickeys would not be cheap.

At the end of the day I'm just not clear what problem this solving. It feels like a solution looking for a problem to be honest. If all I am getting out of it is my SAC rate and dive logging... Let's see… Additional cost, additional complexity, all to get me something that I already know (SAC) or already get with my existing DC/BT... no thank you

i

 

[fnog]

What some seem to not grasp... AI, like GPS, is only beneficial to those who need it. A technical diver simply doesn't need that gas information. Technical training provides the ability to manage gas in a predictable and accurate way. Those gas management protocols can't be eschewed because they are critical and integral to the complex planning that must be carried out for a dive - so using AI achieves no real benefit.

We heard loud and clear that AI as a feature has little to no value in tec diving. That should be well integrated by everyone who read the posts by now.

What Richard and I wonder about, is wether such unused feature has a value as a market driver/enabler for an effort on a common hardware in terms of R&D, budgets, testing, qualification, and test user base. In that sense, a feature that is useless and unused could still be beneficial to the tec divers, and it could even be a win situation for rec divers too if the hardware and the test protocols are done to the standards of tec from scratch (hum...maybe my wording is not very clear compared to Richard's...). On this hypotetical tec/rec multimode DC chip, the AI part would be completely disabled in the tec firmware, reducing the software development costs, increasing simplicity.

Another open question is wether the idea of digital HP gauge added to the trusty SPG would ruin its' reliability, and yet another is wether it is feasible at all to transmit data without turning the spg casing into something bulky, fail-prone, or expensive.

I made no mystery that I am unexperienced in tec and diving in general and that this was a naive question. AFAIC, this discussion is not about my learning of tec diving, I do not know at this point if I ever will. It is squarely about grasping wether in the mid term the development of tec and rec DCs could be united or not, and motivated by that curiosity. A bit pointless, I admit, but hell, is this a forum from the intarwebs or not ?

If you think that this kind of blue-sky talk is endangering the conservatism that is a necessary part of tec diving discipline, please think again. My impression is that most people can tell the difference.