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gcbryan
August 30th, 2009, 03:56 AM
This is an open ended question for anyone with the knowledge to answer...

1)What are the limiting factors preventing a Liquivision X1 type of display from being used in hockey puck $400 type of computers? I assume cost, battery considerations, and perhaps size of the enclosure but I don't know for sure. Also what is the chance of the component cost coming down dramatically?

2.What are the memory requirements/limitations for entry level hockey pock computers? How feasible would it be to have display user controllable much like you can control your "desktop" with Windows.

3.How hard/what cost considerations would there be for entry level computers to have software choices so that you aren't stuck with Buhlmann derived algorithms or having to ignore your computer on occasion because what it's recommending is not what you feel to be best?

Just in general, need all of these features only be in very expensive computers? Is there anything inherent (other than the display question) in these changes that have to involve great cost?

With respect to the display question if cost is the main issue I'm wondering what the volume differences are between for instance Liquivision and Oceanic. You would think Oceanic would have some volume advantages (but probably not enough at present to be used in low cost models).

fnfalman
August 30th, 2009, 12:35 PM
I'm not familiar with the Liquidvision. I know what it is but I have yet to see how it works. But how much display do you need? You have bottom time, pressure reading (AI computer), depth reading, nitrogen loading, oxygen loading and ascend rate. What else need to be shown?

As far as selectable deco algorithm, the Oceanic OC-1 allows you to select either the modified Bulhman (RGBM) or the Haldanian algorithm that most recreational computers use.

Kern
August 30th, 2009, 12:45 PM
I'm not familiar with the Liquidvision. I know what it is but I have yet to see how it works. But how much display do you need? You have bottom time, pressure reading (AI computer), depth reading, nitrogen loading, oxygen loading and ascend rate. What else need to be shown?

He's talking about the OLED display



As far as selectable deco algorithm, the Oceanic OC-1 allows you to select either the modified Bulhman (RGBM) or the Haldanian algorithm that most recreational computers use.

It uses Buhlmann ZHL-16C, nothing to do with RGBM.

TheBigPhillyFish
August 30th, 2009, 02:08 PM
The liquidvison are intended for OC technical diving, and CCR's. Unless you intend to get into either one of those, don't even bother. And as far as I am aware of, the Liquidvision does not support air intergration, only offers O2 sensor for CCR.

It all depends on what your looking for in a DC. By the sounds of it you want a DC thats not so conservative. There is plenty out there to choice from. And another question you need to ask yourself, do you want or need wrist mounted?

I could list a few to look into:

Oceanic OC1 is nice it allows the user to switch between two algorithms, and also allows programing of additional safety levels, it also has air integration. It allows 3 mixes, O2 21-100%. Downfall, pricey msrp $1850, $1500 with out transmitter.

Scubapro / Uwatec Galileo and Galileo Luna IMO one of the better of the recreational DC's. Is wrist mounted and air integrated, offers 3 gas mixes from 21-100% O2, and has an electronic compass, which is considered one of the better on the market. Can also read up to 4 transmitters. This DC also has a very large data logbook. This is a middle of the road DC, the diver can program up to 6 micro-bubble levels for increased safety. MSRP $1350

Sherwood Wisdom 2 is a console mounted air integrated DC. At this time I personally use this DC. ITs air integrated with quick disconnects. Its a very liberal DC with very large easy to read numbers. The one thing I really like about this DC is the safety stop timer. It is very easy to navigate through the settings. Will do nitrox I believe up to 40%. MSRP $895, you can usually find these pretty cheap around the 400-500 mark.

Oceanic VT3 is a wrist mounted air integrated DC. This DC offers the ability to monitor 3 transmitters and 3 different nitrox gasses. This DC has a large face for a wrist mounted DC. I have actually tried one of these at an Oceanic event and loved it. This DC also offers a safety stop timer. It has a surprisingly easy to read face. MSRP 999.00

Aeris Elite T3 is a wrist mounted air integrated DC. This DC also offers the ability to monitor 3 separate transmitters and allows for 3 different gases up to 100% 02. The large face is easily readable. I have also tried one of these, and I put it in the same class as the Oceanic VT3. I believe this and the VT3 actual computer and algorithms are made by the same company just put in different shells and sold under different names. MSRP 999.00

Other air integrated DC's to consider Oceanic Atom 2.0, Aeris Compumask, Suunto D9 and Vyper, Uwatec Aladin Smart Tech. And also remember there is plenty of non integrated wrist mounted DC's out there.

I can honestly say if I was looking for a recreational DC right now I think I would be looking at the Scubapro/Uwatec Galileo Luno. I like the features this DC offers, and having an electronic compass is really nice. I also prefer the large square screen to the smaller screens of the round DC watch type. But don't take anyone word for it. Find a local dive shop that carries what your choices are and try them out. Make sure the fit is what your looking for, also make sure they offer safety stop timers, and find out if its conservative, middle of the road or liberal algorithms. I hope this was somewhat of a help! Goodluck.

ianr33
August 30th, 2009, 02:11 PM
Whats this "Liquidvision" computer people keep talking about?

mkutyna
August 30th, 2009, 02:28 PM
liquidvision - Google Search (http://www.google.com/search?source=ig&hl=en&rlz=&=&q=liquidvision&btnG=Google+Search)

The very first link.

ianr33
August 30th, 2009, 04:31 PM
Oh ! You mean the LIQUIVISION ;)

gcbryan
August 30th, 2009, 07:10 PM
The liquidvison are intended for OC technical diving, and CCR's. Unless you intend to get into either one of those, don't even bother. And as far as I am aware of, the Liquidvision does not support air intergration, only offers O2 sensor for CCR.

It all depends on what your looking for in a DC. By the sounds of it you want a DC thats not so conservative. There is plenty out there to choice from. And another question you need to ask yourself, do you want or need wrist mounted?

I could list a few to look into:

Oceanic OC1 is nice it allows the user to switch between two algorithms, and also allows programing of additional safety levels, it also has air integration. It allows 3 mixes, O2 21-100%. Downfall, pricey msrp $1850, $1500 with out transmitter.

Scubapro / Uwatec Galileo and Galileo Luna IMO one of the better of the recreational DC's. Is wrist mounted and air integrated, offers 3 gas mixes from 21-100% O2, and has an electronic compass, which is considered one of the better on the market. Can also read up to 4 transmitters. This DC also has a very large data logbook. This is a middle of the road DC, the diver can program up to 6 micro-bubble levels for increased safety. MSRP $1350

Sherwood Wisdom 2 is a console mounted air integrated DC. At this time I personally use this DC. ITs air integrated with quick disconnects. Its a very liberal DC with very large easy to read numbers. The one thing I really like about this DC is the safety stop timer. It is very easy to navigate through the settings. Will do nitrox I believe up to 40%. MSRP $895, you can usually find these pretty cheap around the 400-500 mark.

Oceanic VT3 is a wrist mounted air integrated DC. This DC offers the ability to monitor 3 transmitters and 3 different nitrox gasses. This DC has a large face for a wrist mounted DC. I have actually tried one of these at an Oceanic event and loved it. This DC also offers a safety stop timer. It has a surprisingly easy to read face. MSRP 999.00

Aeris Elite T3 is a wrist mounted air integrated DC. This DC also offers the ability to monitor 3 separate transmitters and allows for 3 different gases up to 100% 02. The large face is easily readable. I have also tried one of these, and I put it in the same class as the Oceanic VT3. I believe this and the VT3 actual computer and algorithms are made by the same company just put in different shells and sold under different names. MSRP 999.00

Other air integrated DC's to consider Oceanic Atom 2.0, Aeris Compumask, Suunto D9 and Vyper, Uwatec Aladin Smart Tech. And also remember there is plenty of non integrated wrist mounted DC's out there.

I can honestly say if I was looking for a recreational DC right now I think I would be looking at the Scubapro/Uwatec Galileo Luno. I like the features this DC offers, and having an electronic compass is really nice. I also prefer the large square screen to the smaller screens of the round DC watch type. But don't take anyone word for it. Find a local dive shop that carries what your choices are and try them out. Make sure the fit is what your looking for, also make sure they offer safety stop timers, and find out if its conservative, middle of the road or liberal algorithms. I hope this was somewhat of a help! Goodluck.

I think you missed my point. I have several dive computers. I'm wondering if cost and any other considerations will soon if not now make it possible for OLED display technology to be made available in less expensive wrist dive computers.

I'm also wondering why (memory issues) displays aren't more user configurable...depth on top, runtime below, NDL smaller and over to the side, etc.

And I'm wondering why there aren't more choices in algorithm so that computers can match dive buddies or desktop software. Really knowing and controlling what is in the computer not just settings to make whatever is in their more conservative....Buhlmann ZHL16C and VPM-B etc.

I thought maybe some EE's out there would have info on cost for OLED and the feasibility of the other issues I've raised.

It was more about the ideal (for me) computer.

ianr33
August 30th, 2009, 07:14 PM
And I'm wondering why there aren't more choices is algorithm so that computers can match dive buddies or desktop software. Really knowing and controlling what is in the computer not just settings to make whatever is in their more conservative....Buhlmann ZHL16C and VPM-B etc.

You could always program your own computer
HeinrichsWeikamp GbR (http://www.heinrichsweikamp.net/old/ostc/en/)

gcbryan
August 30th, 2009, 07:53 PM
You could always program your own computer
HeinrichsWeikamp GbR (http://www.heinrichsweikamp.net/old/ostc/en/)

Thanks for the link. I hadn't seen that one. Peter Rachow in Germany has a site for a DIY project but the computer is very large and not particularly high tech.

This one is interesting. It still has a high price tag though.;)...actually I'm not sure what the price is. Is the symbol being used the Euro symbol?

Kern
August 30th, 2009, 09:16 PM
OLED displays are more expensive than LCD's. They use more power than an LCD. Therefore battery usage goes up, so power supply requirements go up adding to the expense. There are also longevity issues with OLED.

If you want to run algorithms more complex than a neo Haldnian type you need a CPU with more power so it can crunch enough numbers to do it in real time, therefore more expense. Such a CPU is not only more expensive in itself, but they require more power, so once again the power supply needs to be increased.

ianr33
August 30th, 2009, 09:29 PM
Yes. thats a Euro symbol.

I recently bought a Shearwater Pursuit. Algorithm is Buhlmann ZHL-16C . It allows pretty much any user definable gradient factor to be used. That means you can match just about any profile you want with it. I much prefer that to a manufacturers "conservatism factor" (even though it does not have a heart rate monitor ;) )



. There are also longevity issues with OLED.

Could you hazard a guess as to the likely lifetime of the screen on the Liquivision?

kanonfodr
August 30th, 2009, 09:45 PM
OLED displays are more expensive than LCD's. They use more power than an LCD. Therefore battery usage goes up, so power supply requirements go up adding to the expense. There are also longevity issues with OLED.

I don't mean to be a troll, but OLED displays actually use less power than comparable LCDs because they don't require the battery-crushing backlight that LCDs do.



If you want to run algorithms more complex than a neo Haldnian type you need a CPU with more power so it can crunch enough numbers to do it in real time, therefore more expense. Such a CPU is not only more expensive in itself, but they require more power, so once again the power supply needs to be increased.

That is very true. But I don't see how it would be much of a problem to cut, say, a Buhlmann algo that has been modified for less conservatism and upload it to the computer. Granted, one doing so would need to really know his stuff in several areas to be safe.

But I believe that the Liquivision gives the diver the opportunity to plan his dive on DecoPlanner and then transmit that plan to the DC, thus the computer and the diver would be on the same sheet of music as far as deco planning goes.

Peace,
Greg

Kern
August 30th, 2009, 10:02 PM
Could you hazard a guess as to the likely lifetime of the screen on the Liquivision?

Not really, when I was trying to find such info prior to making a purchase, I found everything from, OLED's are an expensive piece of garbage that won't last 5 minutes to 20,000 hours. That's not the X1 screen in particular, it hadn't been out long enough at the time, but OLED displays in general. At this date, I can say that there have been some problems with some X1 displays, but I can't tell you what the percentage is.

As my warranty expired recently, let's just say I hope the 10,000 to 20,000 hours will turn out to be the case.

tgsmith
August 30th, 2009, 10:04 PM
But I believe that the Liquivision gives the diver the opportunity to plan his dive on DecoPlanner and then transmit that plan to the DC, thus the computer and the diver would be on the same sheet of music as far as deco planning goes.



I might be missing the point, but I don't get it. Why would you want to import a plan from your desktop planning software into the computer? The point of having a computer is that it's on the fly. Do you mean you define your gases on the PC using desktop planning software and then download this into the dive computer? Or are you actually talking about downloading a decompression plan into a dive computer(Which I can't fathom the purpose of such)? That'd be like viewing a dive table in electronic form that you could have saved $1740 on and just written them down on slates.....

The only decompression computer I knew of that really needed to have stuff imported into it from a PC was the Cochran using it's "Analyst" software. I know with my Shearwater you can set it up on the computer itself......the only thing it does with my PC is upload the dive logs.

When a computer doesn't have the requisite brainpower it effects it's ability to calculate a decompression schedule or function at all. Witness the VR3 with it's infamous, "SEE TABLES" message.

I can't tell you why more computers aren't using the OLED's yet. But I can tell you my Shearwater Pursuit is big, ugly, simplistic, but actually works 100% of the time and costs less than most top-end technical computers. Function over form.

tgsmith
August 30th, 2009, 10:09 PM
I just read that and realized I was kind of rambling and incoherent, or completely off-topic to the question at hand. I was trying to say something, but I got lost. :lotsalove:

eh, oh well. safe diving.


I might be missing the point, but I don't get it. Why would you want to import a plan from your desktop planning software into the computer? The point of having a computer is that it's on the fly. Do you mean you define your gases on the PC using desktop planning software and then download this into the dive computer? Or are you actually talking about downloading a decompression plan into a dive computer(Which I can't fathom the purpose of such)? That'd be like viewing a dive table in electronic form that you could have saved $1740 on and just written them down on slates.....

The only decompression computer I knew of that really needed to have stuff imported into it from a PC was the Cochran using it's "Analyst" software. I know with my Shearwater you can set it up on the computer itself......the only thing it does with my PC is upload the dive logs.

When a computer doesn't have the requisite brainpower it effects it's ability to calculate a decompression schedule or function at all. Witness the VR3 with it's infamous, "SEE TABLES" message.

I can't tell you why more computers aren't using the OLED's yet. But I can tell you my Shearwater Pursuit is big, ugly, simplistic, but actually works 100% of the time and costs less than most top-end technical computers. Function over form.

giles45shop
August 30th, 2009, 10:14 PM
Just to clarify, you don't import your plan from the desktop to the computer. The Liquidvision running VPlanner Live uses the same algorithm as the VPlanner desktop dive planning software. So if you cut tables in VPlanner, and follow the exact profile of your tables, the computer will provide the same result. If your actual dive is different than the tables you cut, the VPlanner Live adjusts on the fly, just like any other dive computer, but it doesn't lock you out like the VR3.

DiveNav
August 30th, 2009, 10:30 PM
....If you want to run algorithms more complex than a neo Haldnian type you need a CPU with more power so it can crunch enough numbers to do it in real time, therefore more expense. Such a CPU is not only more expensive in itself, but they require more power, so once again the power supply needs to be increased.....

I don't agree with this statement .... these days you can get an arm16 based microcontroller with embedded memory, plenty of power to run any deco algorithms you want - and more to spare.
They cost nothing and they consume nothing :D

Prices are high because volumes are low

Alberto

Kern
August 30th, 2009, 10:31 PM
I don't mean to be a troll, but OLED displays actually use less power than comparable LCDs because they don't require the battery-crushing backlight that LCDs do.

I don't mind discussion, I don't actually consider it trolling.

Well, I'm no expert on these things, but when I looked into such things, the consensus seemed to be that OLED need more power than an LCD. Do you leave your backlight on during the entire dive, I cant remember ever turning mine on during an OW daytime dive.



That is very true. But I don't see how it would be much of a problem to cut, say, a Buhlmann algo that has been modified for less conservatism and upload it to the computer. Granted, one doing so would need to really know his stuff in several areas to be safe.

That is in fact my point. You can load any neo Haldanian such as Buhlmann onto any of today's crop of computers. There are however very few presently with the power to run a fully iterative dual phase algorithm in real time. So if VPM-B using V-Planner is my preferred desktop software, & I want a DC that is capable of running that same algorithm, it need's to have a more powerful CPU to do so.


But I believe that the Liquivision gives the diver the opportunity to plan his dive on DecoPlanner and then transmit that plan to the DC, thus the computer and the diver would be on the same sheet of music as far as deco planning goes.

Peace,
Greg

Stop believing, start knowing. :) Sorry couldn't help myself, but that's not the way an X1 works.

ptyx
August 30th, 2009, 10:50 PM
I might be missing the point, but I don't get it. Why would you want to import a plan from your desktop planning software into the computer?
Not import, but define. So the computer can remind you to switch gas, tell you the optimal ascent rate, etc. Also according to some X1 VPM software FAQ, deco computations are bidirectional in some situations (http://www.hhssoftware.com/v-planner/faqhelp.html#topten) (i.e. knowledge about available deco gases will impact the dive plan before reaching deco).


Could you hazard a guess as to the likely lifetime of the screen on the Liquivision?

From the X1 manual: The OLED display is rated to retain more than half its initial brightness after 40,000 hours of use.


[...]battery usage goes up, so power supply requirements go up adding to the expense.
That could be a big issue for using the technology on mainstream computers: X1 doc says 30h underwater battery time, and it requires an AC adapter for charging. It would be an increase in manufacturing costs (adapter, dock and connectors) and a loss of convenience which is hard to justify.

gcbryan
August 30th, 2009, 10:53 PM
From my limited research OLEDS use much less power than LCD's. The price is coming down particularly for the smaller sized screens. They are used in some cell phones today.

To Kanondodr as was mentioned that's not how an X1 or any dive computer works. The X1 can load several different deco planners just as one would do on a desktop. Also, no one is trying to make a Buhlmann algorithm less conservative...GF's attempt to do just the opposite however although they could be set to match VPM or any other algorithms runtime they can't produce the same deco profile.

If the open source dive computer mentioned earlier in the thread can be sold for around $1,000 US with OLED's with the very limited numbers they would be producing I'd guess that Oceanic could do the same and sell it at much lower prices...today.

Kern
August 30th, 2009, 10:53 PM
I don't agree with this statement .... these days you can get an arm16 based microcontroller with embedded memory, plenty of power to run any deco algorithms you want - and more to spare.
They cost nothing and they consume nothing :D

Prices are high because volumes are low

Alberto

Once again I'm not an expert & just going with the info I could find at the time. Could you comment how arm 16 chips cost & consumption compares to those used in most DC's today.

Does "prices are high because volumes are low" apply to manufacturers buying the CPU's or the end user buying the DC?

Just for my own interest, do you no what sort of CPU most DC use at the moment? As arm 16 chips cost & consume nothing I wonder why they aren't more common in DC now? Does an arm 32 chip cost & consume nothing?

gcbryan
August 30th, 2009, 11:43 PM
Once again I'm not an expert & just going with the info I could find at the time. Could you comment how arm 16 chips cost & consumption compares to those used in most DC's today.

Does "prices are high because volumes are low" apply to manufacturers buying the CPU's or the end user buying the DC?

Just for my own interest, do you no what sort of CPU most DC use at the moment? As arm 16 chips cost & consume nothing I wonder why they aren't more common in DC now? Does an arm 32 chip cost & consume nothing?

Not being argumentative...I just want to know...do you know that current DC's couldn't handle VPM for sure? The original reason that so many DC's used Buhlmann was simply because Buhlmann was the only one who published a book with enough information in it to actually implement the program. I know some people download VPM into their iPod and other smaller devices.

Regarding prices being high...volume is volume regardless of whether you are looking at it from the point of view of the manufacturer or the end user. If there aren't many end users volume will be low since a manufacturer isn't going to order in large numbers for a small potential market.

Someone like Oceanic that has dealerships worldwide, name recognition and a large advertising budget produces many more computers than a smaller company ever will. Their unit and component costs will be much lower.

For what it's worth, I believe the life issue with OLED's is much improved. Liquivision says something like 40,000 hours. They are being used in some TV screens now. Flat screen's with OLED's can be much thinner than with LCD's.

Kern
August 31st, 2009, 01:49 AM
From the X1 manual: The OLED display is rated to retain more than half its initial brightness after 40,000 hours of use.



Yes, that's what the manufacturer says, but I couldn't find any independent authorities at the time that thought that sort of figure was anything but hyperbole.

On the other hand, technology can move on very quickly.

DiveNav
August 31st, 2009, 02:06 AM
Once again I'm not an expert & just going with the info I could find at the time. Could you comment how arm 16 chips cost & consumption compares to those used in most DC's today.....

My point is that the electronic components per se (processor / memory) are NOT the ones responsible for the overall (high) cost of dive computers. In volume, the difference between an 8 bit microcontroller and a 16bits one is in order of few dollars .... and a 32 bits one is an overkill for the deco algorithms.
From a pure processing power point of view (that drives power consumption), you could easily run the ZH-L16C at 1 Hz sample rate on on a 8 bit m-controller ;)
You don't even need an AD converter because the pressure/temperature sensor comes with SPI.
This means that if you use a 0.18micron CMOS controller (old from a technology point of view ;)) you will probably consume few mW to run the deco algorithm ....
Imagine what you could do using state of the art sub-micron processes ;)

In my opinion the driving factors in the overall DC costs are the mechanical container, final assembly and the final tests.


.....Does "prices are high because volumes are low" apply to manufacturers buying the CPU's or the end user buying the DC?....
Both .... dive computers are not a "mass market" product and the economy of scales are just not there ... for every step .... from device integration, to assembly, test and distribution.
How many dive computers do you think are sold every year worldwide? And how many cellphones?

Alberto

Kern
August 31st, 2009, 02:06 AM
From my limited research OLEDS use much less power than LCD's.

Are we talking about DC screens that don't have constant backlighting or tv & computer monitors that do require constant backlighting. I have to say that most of the info I could find related to tv & PC monitors. The manufacturers certainly hyped the lower power consumption of OLED over LCD prior to bringing them to market. Once again, independent studies seem to indicate that this may not be the case in reality.

Psyonide
August 31st, 2009, 03:49 AM
I really have to agree with DiveNav here- DCs sell in small volumes and with so many equipment manufacturers out there the earning potential is small AFAIK. Technologically speaking there's no doubt in my mind that current DCs aren't exactly top notch, but than again they were never really required to be cutting edge high-tech as the amount of calculations needed is quite limited, no cool graphics, no comm etc. quite basic.
The consensus I'm aware of claims that OLEDs do require less power than LCDs, and if you want to go super high-tec than check Kodak's new submersible flexibles:
Kodak flexible OLED display gets its feet wet (http://previconew.tinyurl.com/nvmwrk)
So this field is really hot today.
Again, there's no doubt in mind that once you take DCs from the realm of diving equipment manufacturers to that of gadget and PC manufacturers- you'll be able to cram much more magic into those little things.
However- bear in mind few key points:
1. Today's PCs limited life expectancy and reliability (exploding iPhones pop to mind).
2. Parts support.
3. Operational depth.
4. Life supporting gear manufacturers rely heavily on years long positive rep.
Add to that the fact that you usually don't expect to upgrade your gear every year and that the market is probably not huge and, well... you get the picture why it's probably still the domain of diving equipment manufacturers and not Dell's. That doesn't mean though that it can't be done.

Kern
August 31st, 2009, 05:44 AM
OK, it looks like I have it all wrong. Apparently an 8 bit CPU running a single phase algorithm will not use anymore power than a 32 bit CPU running a dual phase algorithm in real time. Small OLED displays used in DC's use less power than an LCD display without permanent backlights. The current crop of DC available can all run dual phase algorithms in real time.

gcbryan
August 31st, 2009, 08:40 AM
OK, it looks like I have it all wrong. Apparently an 8 bit CPU running a single phase algorithm will not use anymore power than a 32 bit CPU running a dual phase algorithm in real time. Small OLED displays used in DC's use less power than an LCD display without permanent backlights. The current crop of DC available can all run dual phase algorithms in real time.

Hey, don't get upset...:D I think you are right for the most part. I think the power is less in applications where LCD's must be backlit such as flatscreen technology and you are probably correct that in dive computers they use more power.

Initially, I hadn't thought about the extra processing power for VPM but I'm guessing (that's guessing) that Alberto is correct that it's not a major cost consideration all other things considered.

Regarding the life of the screen it will be interesting to see if the Liquivision owners are still happy in a year or two with the display brightness.

DiveNav
August 31st, 2009, 11:35 AM
.....Initially, I hadn't thought about the extra processing power for VPM but I'm guessing (that's guessing) that Alberto is correct that it's not a major cost consideration all other things considered......

Hey .... I am guessing too .... but it is an educated guess .... I have been in the semiconductor industry since 87 and I have seen Moore 's law in action several times and I have seen cost (cost - not selling price) of GPS receivers (just the rf+baseband processing combination) going from few hundreds dollars to a couple of dollars when demand requested it.

If dive computers were a mass market and were easy to do (from a mechanical / reliability point of view) the Taiwanese / Chinese would be all over it.

Alberto

gcbryan
August 31st, 2009, 06:37 PM
Well, I found out for sure (regarding the OLED issue) that the greater issue (cost) is the power required by the OLED and the fact that this requires rechargeable batteries, extra circuitry, and the recharger itself.

Kern
September 2nd, 2009, 09:02 PM
Hey, don't get upset...:D

Thanx for your concern, but I'm not that upset...

Could you share the source that led you from this...


From my limited research OLEDS use much less power than LCD's.


to this...


Well, I found out for sure (regarding the OLED issue) that the greater issue (cost) is the power required by the OLED and the fact that this requires rechargeable batteries, extra circuitry, and the recharger itself.

gcbryan
September 2nd, 2009, 11:22 PM
Thanx for your concern, but I'm not that upset...

Could you share the source that led you from this...



to this...

Yes, I had a post on DecoStop that Erik Fattah of Liquivision responded to in some detail.

I did read a quote somewhere that Bruce Wenkie (sp?) said that any recreational computer that could run Buhlmann ZHL-16C with Gradient Factors could run a version of RGBM (the more limited version used in Suunto computers).

(Just kidding about you being upset).:D

Liquivision
September 3rd, 2009, 04:26 PM
The Liquivision F1 was the first dive instrument which contained an OLED, and it was released in April 2005. Now, four years later, those units have displays which still look indistinguishable compared to when they were first sold. Perhaps the brightness is down by 10%, too hard to tell.

To run a real bubble model (with no approximations), the CPU is going to burn around 8mA at the very minimum. That means there is no chance of such an algorithm in a non-rechargeable computer.

There is no point comparing dive computers to above-ground 'dry' electronic devices. It is very easy to produce a dry electronic device. On the other hand, underwater electronics require dramatically longer R&D cycles to debug the reliability.

A typical dive computer development cycle involves about 3-4 months to get the circuit, software and mechanics done. This is followed by about 2-3 years of debugging the reliability -- a cycle which is not required for 'dry' electronic devices.


Eric Fattah
Liquivision Products

DiveNav
September 4th, 2009, 11:04 AM
.....To run a real bubble model (with no approximations), the CPU is going to burn around 8mA at the very minimum. .....

Which CPU ?

Usually processing power is measured in MIPS .... and then translated to W based on the hosting platform.

Alberto

Liquivision
September 4th, 2009, 03:19 PM
It doesn't really matter which CPU. To run a bubble model you need at least a 16-bit CPU running at a pretty fast clock rate. Or a 32-bit CPU running at a more modest clock speed. Either way, at the required processing speed, the power consumption is similar. The main determinant of the power consumption would be the silicon technology (i.e. 90nm chip would draw more power than a 65nm chip, etc..)

As IC technology improves and shrinks, power consumption drops, so perhaps it will one day be possible to run a bubble model at 1mA. Today at 1mA you're limited to moving-average style algorithms and compartment models.


Eric Fattah
Liquivision Products

Randy43068
September 4th, 2009, 03:21 PM
I have X1 envy

DiveNav
September 5th, 2009, 06:28 PM
It doesn't really matter which CPU. To run a bubble model you need at least a 16-bit CPU running at a pretty fast clock rate. Or a 32-bit CPU running at a more modest clock speed. Either way, at the required processing speed, the power consumption is similar. The main determinant of the power consumption would be the silicon technology (i.e. 90nm chip would draw more power than a 65nm chip, etc..)

As IC technology improves and shrinks, power consumption drops, so perhaps it will one day be possible to run a bubble model at 1mA. Today at 1mA you're limited to moving-average style algorithms and compartment models.


Eric Fattah
Liquivision Products

That is why I asked about the processing power in MIPS :D

FYI I have spent > 20 years in the semiconductor industry and not too long ago I was the CEO of a fabless semiconductor company ... so I know a bit or two about processors ;)

AM

Liquivision
September 8th, 2009, 04:19 PM
Unfortunately MIPS doesn't tell you much. After all, a 10 MIPS 8-bit processor cannot be compared to a 10 MIPS 32-bit processor, since the 32-bit processor takes way fewer instructions to do arithmetic. The difference is clouded even more if you take into account processors that have FPU, where megaflops is a more meaningful number.

To run a bubble model, you'll need a 32-bit ARM7 running around 5-10MHz, depending on how deep the dive is (as the TTS calculation gets longer the deeper you are).

Eric Fattah
Liquivision Products

Kondado
June 4th, 2010, 06:11 AM
To run a real bubble model (with no approximations), the CPU is going to burn around 8mA at the very minimum. That means there is no chance of such an algorithm in a non-rechargeable computer.

Hello all...

I know this thread is quite some months old, but I preferred to not open a new thread so that it's easier to understand why I am asking what I'm going to ask... ;)

And the question is: if Liquivision says that current DCs aren't able to cope with a "true" bubble algorithm/model, what do the Suunto DCs do when they use the RGBManagement?

I specifically ask for the Suunto-RGBM since from what I've read the Bühlmann ZH-L8 ADT isn't a true bubble-model but it's more sort of a "bubble-patched neo-haldanean model".

Possibly everything I've supposed is wrong, please bear with me. ;)

Actually the final question would be, as of today (June 2010) is there any divecomputer which has a true bubble model?

Thanks

Kondado
June 4th, 2010, 06:32 AM
I'm answering my own question...

I found this thread Sunnto RGBM, what is up with that? - DIR Explorers (http://www.direxplorers.com/dir-decompression-forum/730-sunnto-rgbm-what-up.html)

Seems there's only one DC - the HS Explorer - which implements a true RGBM. That was in the year 2006 but I guess little has changed since then. Suuntos RGBM seems more a marketing thing... quite sad that is, since I actually believed in it. On the other hand, up until today I have no true complaints to my Suunto D4 (for sure there are and will always be better DCs, but more expensive too).

Anyway, more answers are always appreciated.

Kern
June 4th, 2010, 07:02 AM
Hello all...

I know this thread is quite some months old, but I preferred to not open a new thread so that it's easier to understand why I am asking what I'm going to ask... ;)

And the question is: if Liquivision says that current DCs aren't able to cope with a "true" bubble algorithm/model, what do the Suunto DCs do when they use the RGBManagement?

This is what Bruce Wienke has to say on page 12, bullet 4 of RGBM ALGORITHM OVERVIEW: CONCEPTS, BASES, VALIDATION, TESTING AND REFERENCES.....

its a "modified RGBM recreational algorithms (Haldane imbedded with bubble reduction factors limiting reverse profile, repetitive, and multiday diving), as coded into Suunto, Mares, Dacor, ABYSS, GAP, HydroSpace, Plexus decometers, lower an already low DCS incidence rate of approximately 1/10,000 or less. More RGBM decompression meters, including mixed gases, are in the works".



I specifically ask for the Suunto-RGBM since from what I've read the Bühlmann ZH-L8 ADT isn't a true bubble-model but it's more sort of a "bubble-patched neo-haldanean model".

No, Buhlmann is a single phase neo haldanian algo. "M" values would be the only thing you could possably call a hack/patch.



Possibly everything I've supposed is wrong, please bear with me. ;)

Actually the final question would be, as of today (June 2010) is there any divecomputer which has a true bubble model?

Thanks

Sure, the X1.




Seems there's only one DC - the HS Explorer - which implements a true RGBM.That was in the year 2006 but I guess little has changed since then. Suuntos RGBM seems more a marketing thing... quite sad that is, since I actually believed in it. On the other hand, up until today I have no true complaints to my Suunto D4 (for sure there are and will always be better DCs, but more expensive too).

Anyway, more answers are always appreciated.

I'm not sure I believe this. Got a source. See the name of the DC manufacturer I'v highlighted in the excerpt of Wienkes article.

Kondado
June 4th, 2010, 01:16 PM
No, Buhlmann is a single phase neo haldanian algo. "M" values would be the only thing you could possably call a hack/patch.

You perfectly resolved all of my previous doubts. There's just one more question which now arises; you say it's a "single phase neo haldanian something", so... does that mean it doesn't take bubbles into account in either way?

I tought I read something about that... well, somewhere. ;)

Is there any Buhlmann variant which does the bubble-math?

Thanks.

(PS: The ADT seems to stand for "adaptive" and takes the temperature differences during a dive into account, i.e. slower off-gassing because of vasoconstriction at the end of the dive.)

ijdod
June 4th, 2010, 04:01 PM
I don't mind discussion, I don't actually consider it trolling.

Well, I'm no expert on these things, but when I looked into such things, the consensus seemed to be that OLED need more power than an LCD. Do you leave your backlight on during the entire dive, I cant remember ever turning mine on during an OW daytime dive.

One of you is talking about the old-school reflective LCD, which use very little power, and usually uses reflected light to make it readable. A very low power backlight could also do the trick. This is the technology used in digital watches, and most dive computers.
The other is talking about a modern color LCD, which in itself doesn't use much, but requires a fairly power hungry backlight. This is the technology used in laptop screens, PDAs, most smartphones, and dive computers like the Mares Icon HD. All pixels are lit from behind, black is made by blocking the light.
OLED is a fairly recent development, and is found in dive computers like the Liquivision, Uemis Zurich, the OSTC en some others. OLED typically uses less power than the color LCD mentioned above, but (way) more than the reflective LCD.



That is in fact my point. You can load any neo Haldanian such as Buhlmann onto any of today's crop of computers. There are however very few presently with the power to run a fully iterative dual phase algorithm in real time. So if VPM-B using V-Planner is my preferred desktop software, & I want a DC that is capable of running that same algorithm, it need's to have a more powerful CPU to do so.



Stop believing, start knowing. :) Sorry couldn't help myself, but that's not the way an X1 works.[/QUOTE]

Kern
June 4th, 2010, 07:28 PM
You perfectly resolved all of my previous doubts. There's just one more question which now arises; you say it's a "single phase neo haldanian something", so... does that mean it doesn't take bubbles into account in either way?

I tought I read something about that... well, somewhere. ;)

Is there any Buhlmann variant which does the bubble-math?

Thanks.

(PS: The ADT seems to stand for "adaptive" and takes the temperature differences during a dive into account, i.e. slower off-gassing because of vasoconstriction at the end of the dive.)

Sorry, algo is just me being too lazy to write algorithm.

Buhlmann is single phase, it only accounts for gas dissolved in tissues. It does no bubble math. Bubble algorithms are duel phase, they take free gas (bubbles) into account as well as gas dissolved in the tissues.

ADT takes temp into account. So it knows the water temp, how does it know if I'm wearing a 3mm shorty or a dry suit with heavy underwear. That is, it's adapting to the water, not my body. Sounds like more marketing nonsense to me.

Kern
June 5th, 2010, 09:47 PM
Hi Kondado, I'v been thinking about what I'v said about the Buhlmann algorithm & I thought I should elaborate a little. It only pertains to the raw, "vanilla" (unaltered), recreational algorithm.

When doing staged deco dives, most who use Buhlmann these days do in fact apply a patch to alter the output & therefore the shape of the curve. Gradient Factors are applied to raw Buhlmann to change the profile from what is often known traditionally as a bend & mend, come up fast & off gas slowly at a shallow depth model. To one with deeper stops, so you ascend slower & a little less time is spent off gassing in the shallows.

The right Gradient Factors can turn raw Buhlmann curves into something similar to those a bubble model would produce.

Kondado
June 7th, 2010, 04:54 AM
I see. ;) Thanks.

In the following days I'll be hopefully the proud owner of a copy of the Bühlmann book (german 5th edition), which I ordered last friday. I know it lacks some parts of the important information but I think it can be quite interesting to read from a "deco-historical" point of view and to get some insight into the basics of deco-theory.

Kondado
June 10th, 2010, 11:53 AM
I found this in Bruce Wienke's "RGBM ALGORITHM OVERVIEW:
CONCEPTS, BASES, VALIDATION, TESTING
AND REFERENCES"


The HydroSpace EXPLORER is a mixed gas decompression meter for technical and
recreational diving, as are the ABYSS and GAP software vehicles. The EXPLORER is the first ever
full RGBM computer for all diving.

Just for the sake of completeness. Seems to me a bit like a contradiction with the other excerpt Kern posted... but well...

Kern
June 10th, 2010, 10:47 PM
I found this in Bruce Wienke's "RGBM ALGORITHM OVERVIEW:
CONCEPTS, BASES, VALIDATION, TESTING
AND REFERENCES"


The HydroSpace EXPLORER is a mixed gas decompression meter for technical and
recreational diving, as are the ABYSS and GAP software vehicles. The EXPLORER is the first ever
full RGBM computer for all diving.

Just for the sake of completeness. Seems to me a bit like a contradiction with the other excerpt Kern posted... but well...

I love it, not only have you found a source for what you were told, its in the article I used to contradict it.

What can I say, its RGBM, its proprietary, outside of Wienke & the manufacturers, who can know the truth?

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