Thoughts on AI?

[tbone1004]

@Chase Kaplan I'm in a similar boat to @boulderjohn where I was opposed to it until I had it. I had my computer stolen so had to replace it and wanted the smaller profile of the Perdix. I said what the hell and grabbed a pair of transmitters mainly for sidemount use, but it's also been great on the rebreather.
Is it advantageous in doubles? I haven't found it to be advantageous for that for the reasons outlined above, but in sidemount it is certainly nice. Where I put my tanks, the spg's down like the Razor crowd are incredibly difficult to see. If I'm on a scooter I have to stop because it is definitely a two hand operation. If they are mounted up like Edd teaches, then it's fine for one-hand viewing, but it adds clutter to an already cluttered chest and you have to be very careful when rigging tanks to make sure they don't sag and drag nice gouges in the floor of the cave. AI has it right on my wrist and I can monitor it there.
For the rebreather it's the same thing. It allowed me to get rid of a pair of SPG's on my chest which was quite nice.

I was against AI for a long time, largely because there wasn't a computer with AI out there that I would actually consider buying, and those that had it were significantly more expensive. Now that the Perdix AI is only about $80 more than the regular Perdix, there's an unobtrusive way to monitor both gases, and it's a great computer, I think it's something that more should consider if they are in the boat of having to buy a new computer. Is it something worth "upgrading" to if you already have a Petrel or a Perdix non-AI? Obviously not, but if you are buying a new one, it's worthwhile IMO.

I agree with @Kevrumbo that if you are using metric SPG's that the GTR feature is largely useless and I certainly don't use it, but for me it was all about the convenience of having the information on my wrist vs. having to look in two different places and that was worth the money for me. Your mileage may vary.

 

[J-Vo]

As @boulderjohn said, it's very nice for sidemount. This is especially true if you are carrying several deco/stage tanks. I do however keep 1' button gauges on the top of my regs for backup. They are low profile enough not to get in the way and I find them easier to read then down the tank configurations.

There was one occasion where I replaced the batteries with incorrect o-rings. Flooded both AI transmitters on the first dive of my trip. No one had the correct o-rings, so I plugged the ports and used the button gauges the entire trip. Those little guys saved my trip.

 

[broncobowsher]

My thought, feelings, observations... Which are likely to be different than yours.

Nothing against adding AI as an additional monitoring. In the tech world it is generally about redundancy and simplicity. Where I see the best advantage to AI is data logging. Being able to go back later and pull bits of data. But I wouldn't count on it for everything. I've seen and heard enough people complain about dropped signals that I would not trust them 100%.

In sidemount you need to know the pressure in each tank. If you lost a transmitter you are blind to what is in that tank and when your switch points are at. Now to diverge on the button vs. lollipop gauges. The larger face of the lollipop is needed when you are trying to make precise switch points (and making notes for logging). The button gauges are too broad. With that I run a button gauge on my rebreather bailout. I'm not trying to track anything there, I just need to know it is full when I start and it is turned on. If doing AI in sidemount I can accept dropping from the lollipops to button gauges. Much harder to read (for those of us getting on in years for example) but just functional enough to still make safe and correct switches.

For doubles, a real gauge on one post, AI on the other. Don't match? Isolation valve got closed. Again, post dive data analysis is where I see the best benefit to AI.

The "fewer hoses" argument doesn't work for all the rebreathers. My Revo there isn't room to mount any transmitters. Generally shorter hoses are used and the transmitters are located toward the top of the unit where there is usually a little more room. I do have AI on the shearwater that came with the Revo, but have not forked over the $700 in transmitters. On one side I kind of want to do it, but have not really found good justification.

A fault I have heard a few times that would apply mostly to sidemount and rebreathers is the transmitters shutting down and going to sleep when there isn't any (significant?) change in pressure. The transmitter goes into battery saver, not diving mode.

Adding in failure points is another thing I have against AI. Yet another battery (or two) that have to be working perfectly. If you have an analog backup to the transmitter you are still good to go.

So I am not opposed to them at all. I don't put complete confidence in them to run the dive. But there are some advantages that they can offer.

 

[Scuba Scott]

I, personally, would not see myself using AI as I much prefer the reliability of the spg

Nobody has managed to convince me yet that the analog SPG is more reliable than AI.
Sure you have to maintain batteries but if you check the voltage once in a while you don't really need to worry about one dying mid dive. I look at mine weekly... even a once a year diver could just replace the super cheap batteries every year.
Lose the signal? No biggie. Move your wrist until it connects again. You should have an idea where your pressure is so a delay of a few seconds to read it shouldn't be a problem. (I notice losing tank pressure for a couple seconds once every hundred dives or so)
What if the pressure sensor outright fails? You are probably more likely to notice the problem right away with AI than an analog SPG .
Like metric? My Perdix will show PSI or Bar.

I'm not saying AI is better or more reliable. Just that I don't believe it is less reliable.

 

[Caveman]

@Chase Kaplan I'm in a similar boat to @boulderjohn where I was opposed to it until I had it. I had my computer stolen so had to replace it and wanted the smaller profile of the Perdix. I said what the hell and grabbed a pair of transmitters mainly for sidemount use, but it's also been great on the rebreather.
Is it advantageous in doubles? I haven't found it to be advantageous for that for the reasons outlined above, but in sidemount it is certainly nice. Where I put my tanks, the spg's down like the Razor crowd are incredibly difficult to see. If I'm on a scooter I have to stop because it is definitely a two hand operation. If they are mounted up like Edd teaches, then it's fine for one-hand viewing, but it adds clutter to an already cluttered chest and you have to be very careful when rigging tanks to make sure they don't sag and drag nice gouges in the floor of the cave. AI has it right on my wrist and I can monitor it there.
For the rebreather it's the same thing. It allowed me to get rid of a pair of SPG's on my chest which was quite nice.

I was against AI for a long time, largely because there wasn't a computer with AI out there that I would actually consider buying, and those that had it were significantly more expensive. Now that the Perdix AI is only about $80 more than the regular Perdix, there's an unobtrusive way to monitor both gases, and it's a great computer, I think it's something that more should consider if they are in the boat of having to buy a new computer. Is it something worth "upgrading" to if you already have a Petrel or a Perdix non-AI? Obviously not, but if you are buying a new one, it's worthwhile IMO.

Agreed. It would certainly be a far better investment. One thing I would like to ask though Tom, is does the AI slow down the functions of the Perdix in any way? Might sound like a bit of an odd question on the offset but I mean, for example, many electronic items out there start off very fast but then start to slow down and perform poorly as more functions are crammed into it. Is this the case or is the Perdix AI the exact same brilliant computer with or without the AI enabled?

 

[tbone1004]

Agreed. It would certainly be a far better investment. One thing I would like to ask though Tom, is does the AI slow down the functions of the Perdix in any way? Might sound like a bit of an odd question on the offset but I mean, for example, many electronic items out there start off very fast but then start to slow down and perform poorly as more functions are crammed into it. Is this the case or is the Perdix AI the exact same brilliant computer with or without the AI enabled?

I noticed no difference in speed with it on and off. Doesn't mean it isn't there, but with so little actual processing going on with these computers compared to what they're capable of doing, you aren't going to notice anything if it's there and would need a computer to detect it.

 

[Charred]

Can someone provide evidence that spg are more reliable than the AI used by Shearwater?

This is stated and restated often but I have only ever seen opinion to back up this claim.

 

[broncobowsher]

The battery in the transmitter is dead. Which one will work, the analog gauge or the AI?

 

[PfcAJ]

Nobody has managed to convince me yet that the analog SPG is more reliable than AI.
Sure you have to maintain batteries but if you check the voltage once in a while you don't really need to worry about one dying mid dive. I look at mine weekly... even a once a year diver could just replace the super cheap batteries every year.
Lose the signal? No biggie. Move your wrist until it connects again. You should have an idea where your pressure is so a delay of a few seconds to read it shouldn't be a problem. (I notice losing tank pressure for a couple seconds once every hundred dives or so)
What if the pressure sensor outright fails? You are probably more likely to notice the problem right away with AI than an analog SPG .
Like metric? My Perdix will show PSI or Bar.

I'm not saying AI is better or more reliable. Just that I don't believe it is less reliable.

“It’s not less reliable, I just have to do all these things to make it not fail”

 

[jgttrey]

I think the question is "reliable enough" not "as reliable as a good spg." I think AI is clearly good enough for most applications - meaning that if you see the utility for yourself, the reliability difference is no biggie as long as you've been thoughtful about it.

But "as reliable"? No way. I'm not saying "no" to AI, nor do i or anyone else have peer reviewed statistics, but be serious. The failure of either the transmitter or the computer by flood, dead battery, bad oring, dumb DM unscrewing it instead of tank valve, etc... I've seen far more issues, most trivial and solvable to be sure but still issues, with AI than SPGs even though the sample of AI is much smaller.

I'd also keep at least a button on first stage with AI if for no other reason than being able to get a tank pressure when setting up. It's a PITA to have to fetch and power up your computer just to see if you got a full cylinder.