What I want, and I bet I'm not the only one

[tbone1004]

it's actually 3.7, just 4.2 when fully charged. same nominal voltage as the lithium coin cells.

The screen is 1.7", so that makes each side about 1.2" of the screen, so we'll be generous and give it a 1.5" square. call it 40mm. You need the o-ring, and sealing faces for the outer shell and all that. A circle then needs to fit inside of it, so with threads and another o-ring, the largest diameter you can get is around 30mm. Largest square inside of that is 21mm. For reference, a standard 400mah flat battery cell is 50mmx22mmx4mm. So to get it in there, you'd have to double the thickness if you can get a battery mfg to make a custom cell and now you have 8mm of battery, plus at least 3-4mm for the door, and then the rest of the watch. would be an inch thick. you gain nothing. They make a 25x20x5mm lipo battery that would fit, but again thickness is a problem, and the capacity is 170mah, so you lose a lot to gain a less reliable design and convenience for something that doesn't actually matter in the real world.

If the battery lasts 2-3 years and you have to pay $150 to replace it, so what, it's not the end of the world. With Scubapro, price may actually come down, who knows, but the price you pay for a watch sized computer with a screen like that is you have to use a sealed design. Huge part of the reason seabear was the first to do it, it's not easy to do, otherwise the other guys would have done it years ago and the reason they're still using the casio style screens. They take almost no battery power so they can use tiny batteries and have a long service life. If you had to change the battery every 15 hours, it would get real old real fast and you'd be at an infinitely higher risk of a flood than having to pay $150 every 2-3 years at the worst case to replace the battery

 

[Centrals]

I want a high quality, hoseless, air integrated, wrist computer that runs Buhlmann ZHL-16C with GF, a max of 3 gases (don't need trimix or CCR). I would like it to track O2 exposure with NOAA tables and a 90 minute elimination half life, unlike PPS rolling 24 hour window. The majority of my dives are no stop, but about 7% are light deco. I dive hard, often 4 dives per day, multiple days.

So...neither Shearwater or Heinrichs Weikamp are going to build this computer, who will? Under the Scubapro umbrella, will Seabear fit my need? The Hollis TX1 is pretty close it weren't for the O2 tracking algorithm. Both of these computers have more features than I want

I used to dream about a computer that has everything that I needed. But I given up the idea after couple of yrs because none was available and still isn't. So I am still diving with an ageing Uwatec Nitrox Pro and using two BT for tec dive.

The argument on the size/capacity of the battery(rechargeable or not) is interesting. Perhaps the technology is NOT here yet.

 

[tridacna]

With Scubapro, price may actually come down

Hilarious.

That would be the first time I saw "SCUBAPRO" and "LOWER PRICES" together. Let's wait this one out...

 

[Centrals]

Hilarious.

That would be the first time I saw "SCUBAPRO" and "LOWER PRICES" together. Let's wait this one out...

It used to be quite reasonable to pay US$50.00 for the change of battery for Uwatec computer in every 3-4yrs. But when SP took over, the cost went sky rocketing. So I learnt how to do it through SB and now it only costs me $10.00 for the bother.

 

[hroark2112]

If I would have wanted your opinion regarding AI, I would have asked for it. there have been many discussions on the topic. I asked a very simple, specific question, thanks

Touchy!! That time of the month?

Because the technology is available and useful. Same reason most people prefer this

View attachment 221223

over this

View attachment 221224

There is lots of technology available out there to do all kinds of things. Not all of it is worth putting in the water.

Here's the thing. The companies that have the ability to do "What You Want" have decided they don't want to do it. The vast majority of the divers using computers with the features you're looking for do not want bells & whistles like AI. The ability to monitor multiple tank pressures on their wrist just isn't something they want or need. Most of the divers using those computers consider the transmitters to be an unnecessary failure point and prefer to rely on a simple mechanical gauge.

I've got an AI computer. When I was new to diving, I thought it was the bee's knees. Once I got a real handle on my air consumption, I found the need for AI - along with the constant loss of signal - to be a waste.

Obviously there are not enough out there who "Want What You Want" to make it worth any manufacturer's time to bring it to market. I guess you'll have to just do it yourself if you want it.

 

[drrich2]

Since A.I.'s desirability has once more entered a thread as a point of debate, & some people may not've read about it in others, a brief recap.:

1.) A.I. = air-integrated; the computer measures & displays your remaining gas pressure.

2.) You can get A.I. in console computers on a hose, or on wrist computers with a wireless transmitter attached to a high-pressure port on your 1st stage of your regulator.

3.) People talking about A.I. are often referring to wireless A.I. wrist computers. Some such computers can be bought without the transmitter, in which case they may not cost all that much more than non-A.I. wrist units, but on average, an A.I. wrist unit with transmitter costs more than a non-A.I. wrist unit. This difference can run a few hundred dollars. Compare an Oceanic Atom 3.1 with a Geo 2.0, for example.

3.) Many divers prefer wrist units so they can get their depth & NDL at a glance, on their wrist, and some like A.I. so they can see gas pressure there, too.

4.) A.I. is not strictly necessary; people dove before it existed. But it's a nice optional feature some people value & some don't.

5.) Wireless transmitter reliability of signal reception by computer is debated, but on the whole, seems good, and if you lose connection, it's usually regained quickly. Often mentioned, and probably not a tangent to go off on here.

6.) Most recreational divers dive one gas, & likely one tank. There is no issue with diving a number of tanks with different gas mixes, each needing a different transmitter, unlike in some technical diving.

7.) You will see in other threads that, as a general trend (with individual exceptions), rec. & tec. divers have some significant differences in how they view dive planning & gear. Many tec. divers see no benefit in wireless A.I., and then some seem to resent it, to be quick to advise new rec. divers away from computers that have it, or at least that's been the impression of some.

8.) If your computer supports dive logging & download to PC, an A.I. computer can record your start & end tank pressures & calculate your SAC rate, and put it in your computer dive log without you having to bother. I like this.

9.) Wireless transmitters stick off the 1st stage & can be mistaken for a tank valve, & if the tank is lifted by one, can get damaged.

10.) Shearwater, the maker of the Petrel, a computer much loved in the tec. diving community & by some rec. divers, neither makes nor intends to make an A.I. Petrel. Some rec. divers would like one. Some tec. divers are opposed to diversion of resources to produce such a thing, or don't want added technological complexity in theory increasing risk for computer failure, or just plain don't seem to like the idea of an A.I. Petrel, so anyone wanting A.I. has to do without or write-off the Petrel as an option.

Forum tradition holds that these points are made & remade back & forth in at times testy debate. I hope I've summed up the relevant views compactly to save time.

Richard (still hoping Atomic Aquatics makes a wrist version of the Cobalt).

P.S.: What about that new LiquiVision Omnix? How appealing is it?

 

[RonR]

Thanks Richard, we’re working on that wrist Cobalt. It will do most of what the OP wants. Maybe everything after a few firmware updates.


Tbone is correct in what he says about batteries, but in addition, it’s not only the low capacity of the coin cells that limits them to very low power system, it’s that the chemistry can’t deliver enough current to come close to powering a color display at all.


Power density of rechargeable batteries is much less than primary (non-rechargeable) cells. It varies, but a typical AA primary cell might be 2600- 3000 mAh @ 1.5v. The same size in a lithium-ion rechargeable will be around 800 mAh @ 3.7v. Trying to fit a rechargeable of reasonable capacity for the needs of the system (this is mainly driven by screen size for color displays) into a thin wrist form is very difficult. The flat prismatic batteries have the best size to power ratio, but don’t fit into cylindrical containers that are easy to seal and make user changeable. And for cylindrical batteries, you need to allow for O-rings, enough strength in the case, threads to close the top… bottom line, it’s pretty hard to make a strong enough and well sealed battery container for a AA sized battery that’s much less than about 7/8” thick. For a 32mm square prismatic, which you could probably get, you would have to have seals and a door that would resist quite a lot of pressure- and it would need to be square to fit in a product the size of the H3. The closest I find with a quick search is 600mAh and 5.1mm thick. If you want to isolate the battery from the electronics and protect from flood, that adds more size and thickness and you need to figure out how to seal the electrical connections. It all could be done, but it all adds thickness.


On the Cobalt console, we did go for a battery that, while a dealer replacement is preferred and it's not an off the shelf item, can be changed by a user. It’s located in a compartment that is sealed from the electronics, so a flood would not compromise the rest of the system. That definitely added thickness, and after seeing how this worked in the field, I don’t know that I would make that decision again. So few batteries have needed to be replaced in the five years the Cobalt has been shipping that the additional thickness and complication (every seal is also a potential leak) is probably not worth it. I have many batteries here that have been in use for over 7 years, and we have had very few batteries go bad- unless from leaks or physical damage. A required factory change would impact very few users.

Dive computer batteries, for the most part, don’t get used as hard as cell phones, so one would expect them to take a long while to reach the 500-700 charging cycles the batteries are rated for. With each full charge typically giving 40-50 hours of diving, we expect most users will never replace a battery, even though they can. These batteries typically “fail” by gradually not holding the rated charge and not lasting as long in fuse, so it’s not like a hard fault or a dead primary cell.


There are ways to work with these size limitations and get a thinner computer, but they involve some creative design concepts.

-Ron

 

[scubadada]

Why is AI a deal breaker? A simple 2" gauge works great, and you should have a feel for where your tank pressure is before you look anyway!

I should not have been so curt in my reply. I did not give all the information. I dive with an AI primary but have a non-AI computer and a SPG as backup. I would continue to dive this way

---------- Post added December 17th, 2015 at 03:22 AM ----------

Edit: oh yeah, and +1 and thanks for mentioning TX1. Looks like the one I'll be upgrading to when/if that happens -- unless your wish comes true first.

And it can be had for $715, complete, a touch less than the Petrel

---------- Post added December 17th, 2015 at 04:02 AM ----------

...Regarding Trimix, I have to say that with the options available nowadays for recreational trimix and Helitrox, and the benefits I keep being told about regarding diving with Helium on dives to 100' or more, I, personally, would not buy a new computer like you're describing that didn't support Trimix.

You might not feel like you have any need for Trimix now, but why buy a computer like you want that doesn't have the capability? Are you that confident that won't ever decide to add Helium to your arsenal?...

I'm a dozen years older than you with at least ten times the dives. I'm very happy with my current diving and don't anticipate any significant changes. I dive nearly entirely within recreational limits, very occasionally below 130 feet, about 1%. The vast majority of my dives are no-stop, about 5% with very light deco. Nothing is certain, but it is very unlikely that I will pursue additional training /technical diving.

That being said, even though I wouldn't need it, I'd be glad to use a computer with the capability and simply not use it. I don't need the 3 gases my current VT3 has.

---------- Post added December 17th, 2015 at 04:11 AM ----------

...Suunto is out because of the algorithm, so is anything AUP comes out with, and we will see what Aqualung does with PPS but it is unlikely for them to stray from the recreational algorithms.

If scubapro comes out with AI for the seabear line that is going to be your only option realistically. Give up on that computer being max 3 gas with no ccr or fixed PO2, if they're spending that much money to do it, they're going to make it capable of running for the technical divers because including that feature won't discourage any customers from considering it, but if they make it 3 gas limited, it removes it as an option for part of the market so it's easier to come out with it and have a recreational mode like they did with the Petrel. If it has enough power to run gradient factors, then extra gasses are nothing but a few lines of code in the programming that are already there from the other computers in the line so better to KISS on that.

I'd be glad to dive an AI H3. The Hollis TX1 is fine, as is, though I dislike the rolling 24 hour NOAA O2 exposure algorithm and wish they would implement the Seiko Epson algorithm with a 90 min O2 elimination half life, like many computers use

---------- Post added December 17th, 2015 at 04:29 AM ----------

The Liquivision Omnix is not on their website yet, it would be interesting to see the manual and review the specs. The Lynx uses GFs but is limited to 3 stock settings, 100/100, 30/85, and 30/75, I would like full control.

Atomic Aquatics uses a proprietary RGBM in the Cobalt, not sure how that would fulfill my wish list requirements

---------- Post added December 17th, 2015 at 04:31 AM ----------

Though battery heavy, this thread has been useful to me so far, thanks to all for participating

 

[hsinhai]

Maybe could just run a zinc and copper probe to create a salt water battery for added capacity. Bubbling probes would add an additional cool factor

 

[guyharrisonphoto]

I am going to wait to see the Liquivision Omnix, and also we should hopefully know by then if the H3 will get the AI.

personally, I am still upset that the T1 is going out of production, its increased thickness yielded double the battery life and that amazing wheel interface. Why is the very best, most advanced design lost to us??