Dive Computer Technology?

[gcbryan]

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]

Hey, don't get upset...

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]

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).

 

[Liquivision]

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]

.....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]

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]

I have X1 envy

 

[DiveNav]

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

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]

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]

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