Atomic Cobalt or Oceanic ProPlus 2.1 ??
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RonR
Contributor
I'm not quite sure I understand what you are asking- there is no function to erase the logbook, it just keeps going. If you went over the 600 hours or so that the Cobalt will store, then the oldest sector would erase on its own. We do provide a function to clear the tissues, intended for using the computers in a rental type of situation.
Why would you want to erase the log book?
Is that +/- 5° over 360°? Is that relative to calibrated 0° or repeatable accuracy within a short time? I care much less about accuracy relative to magnetic or calibrated zero than repeatability within a given power-up cycle. Almost nobody corrects for Magnetic declination or navigates to a chart. Most divers take a reading on the surface and navigate relative to it.
In my experience, swimming a compass course within 5° underwater takes a lot of concentration, highly exercised legs, and practice — especially with a wrist or console mounded instrument. Navy diving training was the only time I ever tried to be all that accurate. Being within 5° over a quarter mile (1320’
is less than 120’, which is a lot harder than it sounds.BTW, Note the spelling error of pressure under Max tank
What is the +/- full range precision of each sensor? I am guessing the depth sensor, which is rated at 200 PSI or 450’, determines full range precision rather than the 330’ limit on the display. Also, what is the range and precision of the temperature sensor (which is not necessarily the same as the operating temperature)?
You might want to include this information in the manual.
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RonR
Contributor
The 5° number that I put out for the compass is just a real world estimate of how close it will be (not absolute, but in relative/ repeatable terms) after typical calibration. Very careful calibration makes it more accurate, environmental factors (like steel ships!) can make it worse. But my point was that it's pretty difficult to read a compass underwater, or as you observe, to hold a course, to this level of accuracy. The precision of the compass sensor itself is greater than this- about 2% over the full 360° scale- but that ends up being not achievable in the real world.
Correct on the depth sensor, the 330' depth limit is a function of the case design and the fact that this is a recreational air/nitrox computer. The depth sensor is accurate on the + side to about .3%, or about a foot at the approximate 400' maximum. On the minus side it is about .03%, or a little over an inch at the same depth. The Cobalt displays the sensor output in mBar on the System Info screen, checking this against an accurate barometer we are typically within a few mBar.
The temperature sensor is in the pressure sensor and is rated at ±2°C over the range of -40°C- 85°C (-40°F-185°F).
Ron
Thanks for the quick reply. +0.3%/-0.03% is impressive on the depth sensor. Any idea on the cylinder pressure?
Along with the others, my congratulations on an impressive product. It is hard to appreciate how difficult it is to make a product easy to understand. You must have done a lot of focus groups.
RonR
Contributor
Yes, the depth sensor is an impressive piece of hardware, very accurate, and it has held up very well for us. The HP sensor spec is ±.4%, though the rest of the circuitry will introduce some additional error. We only display tank pressure to the nearest 10 psi to keep values from bouncing around in a distracting fashion.
Thanks for the kind words. No focus groups- to quote Steve Jobs:
We had a vision of what would make a good interface, and were pretty ruthless about keeping the interface consistent, even when it meant a lot of extra programming effort. We did have a few [-]guinea pigs[/-] test divers who gave great suggestions for improvements over the years, particularly in the layout of the dive screen. Mostly the Cobalt is the result of many years of development. Atomic deserves a lot of credit for their commitment to quality design.
Lots more has happened since we started selling Cobalt, of course, with many new users. One of the fun aspects is that we can look on this as an evolving platform that will continue to improve over time through the input we get from the community of users.
Had you considered an option to turn rounding off so the pressure gauge could be used for partial pressure mixing in the field? Maybe allow turning rounding off manually but default back to 10 PSI resolution with a power down or the sensor getting wet? ±¼% would be better for this purpose, but may be worth considering for future products.
Understood. The problem I have had is everyone keeping proper perspective. What is intuitive is based entirely on previous experience. Working on a product design for a long time heavily skews perceptions. I suppose test subjects would be a better phrase than focus group. They have often jerked me and the design team back to reality to the point of embarrassment.
RonR
Contributor
We hadn't. I will add that to the list for consideration, though. I'd want to make sure the sensor was accurate enough at the upper end.
True. We have always sought lots of feedback, as often as possible from people who had never seen the Cobalt design before. I've often been brought up short by the perceptiveness and insights users offered. When you are very used to a product you are the worst person in the world to test or evaluate it. We made plenty of changes based on those sort of inputs. We started with more graphic representations (pressure and depth) in the dive screen, for instance, but found those were not as easy for divers to understand. That's how the interface was developed, actually- as an iterative process driven by actual users.
Downing
Contributor
Send and bill me for the first wrist mount I'm getting the one now for my wifes birthday present but I want wrist mount. But till I get one, Do you think she would notice if I used it on the Palau trip? No scratches allowed.
A more serious question I would prefer the remaining bottom time to be larger than the no deco time. Is that something that can be programmed- say to switch the dispay around a bit?
I'm getting the one now for my wifes birthday present but I want wrist mount. But till I get one, Do you think she would notice if I used it on the Palau trip? No scratches allowed.A more serious question I would prefer the remaining bottom time to be larger than the no deco time. Is that something that can be programmed- say to switch the dispay around a bit?
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