Thoughts on Air Integrated (hoseless) computers

[diverdoug1]

I knew someone would make this point. Nice try. Yes, accuracy vs. precision is well understood.

Most SPG gauges have 5 marks between each 1000psi marking, and a few have just 3 marks between each 1000psi, so even if they have high precision you cannot determine your exact pressure with any true accuracy. Look here: Scuba Diving Gauges with reviews on sale

So, do you want to estimate your tank pressure to the nearest 100-250psi or do you want to READ 855psi?

What you have said is exactly backwards. Precision is how closely secondary results reproduce past results (and is not reflective of accuracy). Example - a precise rifle has a very small 5 shot grouping (regardles of how close the grouping is to the targeted spot). Therefore, most SPG have lower precision than digital (with repect to the reading that is obtained visualy). Accuracy is how close the average result matches the intended result. Example - A rifle that sprays all over the target is still very accurate if the average of its grouping is very close to the targeted spot.

I have never seen a reliable source state that the average analog SPG is any less ACCURATE than the average digital SPG. That does not mean that it is not true. The two measure in two different ways (Bourdon tube, vs electronic pressure transducer. Just not sure if either is better. Never the less, as a fan of scientific method, i just wanted to clarify the accuracy / precision thing.

 

[fppf]

Bourdon tube gauges can be very accurate. Pressure transducers can be made like junk as well.
However, that said, a small bourdon tube is very hard to get good accuracy and the cheap ones most scuba mfgrs sell don't have the best internal parts. Pressure transducers can be very accurate in a small package these days. Most are silicone based button cells that are mass produced and very repeatable.

 

[sierra23]

Good info. I am on my fifth computer 2 have been AI. I have found the most important thing is that you understand and totally trust your instruments. The first AI failed on me three times and I sold it to a dive master. Twice it was the transmitter and one time it was the computer. I now have a Sunto D9 that I trust completely!! I am able to easily read it and gather any information quickly. At first, I went to the AI for less hoses. When my transmitter failed on my first AI, I was on a 3 week dive trip in very remote territory. A lesson learned and I will ALWAYS have an SPG. The battery can only be changed out @ the factory with the D9. I use fresh batteries if I am going remote but also carry another computer that the batteries can be changed out in the field.:cool2:

 

[jd950]

I mean no offense to Suunto users but I don't think I would use a computer that does not provide for user-changeable batteries.

I change transmitter and computer batteries about every 6 months in normal use. It takes about 5 minutes per computer and costs about $10.00-$20.00 per computer, depending on where I bought the batteries. I also carry a few spares on a dive trip.

Just out of curiosity, what does it cost to get a battery change from Suunto and how long does it take to get your computer back?

 

[ScubaSteve]

I mean no offense to Suunto users but I don't think I would use a computer that does not provide for user-changeable batteries.

I change transmitter and computer batteries about every 6 months in normal use. It takes about 5 minutes per computer and costs about $10.00-$20.00 per computer, depending on where I bought the batteries. I also carry a few spares on a dive trip.

Just out of curiosity, what does it cost to get a battery change from Suunto and how long does it take to get your computer back?

Don't quote me on this but I think I paid about $25 to my LDS to do it and they offered to do it while I waited. I had to leave it anyways but for a certified Suunto Rep....it is apparently not a big deal. My back-up computer has user changeable batteries.

 

[jd950]

I didn't know a dealer could do it, that would be better than having to send it back to Suunto.

 

[ScubaSteve]

I didn't know a dealer could do it, that would be better than having to send it back to Suunto.

There may be a difference bewteen a Tech Rep (able to service) and simply a sales dealer....I am not sure. But, that was how mine got done.

 

[Matt S.]

I need to change the battery in my D6. I have been putting it off because I was sure I had to send it to Finland. Time to call the LDS and cross my fingers!

 

[bsumner]

I have no secondary air guage. I have a secondary computer (wrist mounted but not AI). My plan is, that if my AI computer (not hoseless) ever tanks on me mid dive, I call that dive immediately and asced to a safe depth knowing what I had in my tank when last checked (every 3-5 minutes) and finish my dive on my secondary computer by returning to either shore or the boat. I do have an SPG which is not part of my every day rig, so I would be able to mount that for use on subsequent dives if wanted.

I use an Aeris Epic (analog of Atom 2.0) and really like it. There have been a few times when it lost contact with the transmitter, but it has always re-linked within a few seconds. I use a Cressi mini spg/depth gauge console as a backup, just because I don't want to be at 100 ft without this vital information in the event of a transmitter or computer failure. Some might say that the extra hose defeats the purpose of a hoseless AI computer, but the real value to me is having all of the readouts in one place on my wrist, which I can check easily and quickly.

 

[coco240]

Well I myself been looking to update to wireless AI.

I currently been using a Uwatec Aladin Air (AI/hose) computer for 11 years. That thing never failed me. With regard to the precision, it is very precise (Check with calibrated gauge from work), however I agree with an earlier post about the requirement for uber precision. It is my experience that most of my dive down south (Retired my dry suit) have been stop before reaching 1000 psi. Usualy because of some idiot photograph going ape***** against current sucking in his tank.

I have been looking at the Galileo Luna and the Oceanic OC1 but still not convinced to trust the wireless link. What is your actual reliability on your signal.