Lynx: lot lot to like but few Hmm's

[griffon]

So far I like the Lynx but there are a few niggling things that are driving me batty in real word use. This is going to sound all negative because this what I'm focused on here, what I want to see different. I think Lynx one of the best and most innovative computers on the market and happy to own one . That said....

1. Compass access is almost useless, WAY to fidgety to go get a quick reading. I would like to be be able to either quick toggle, single left or right tap, to the compass screen, and back, or better have a alternate screen that keeps just the heading/general compass point up on main screen. I think this would be more useful to me then the big tank icon. Unless I missed it there is also no way way to lock a heading and counter heading indicator nor markers to shortest point mark (turn left to get back to heading fastest rout etc). I would consider all this to be pretty standard when contrasted to other comps with integrated compasses and it's just not there, why? The biggest issue for though is all the tapping and menus just to get in out. That is just not cool when diving IMO. It's like saying don't use this, take a analog too that you can just you know... look at.

2. No deep stops? WTF? really? come on, 2013 now...

3. The safety stop resetting instead of pausing if you dip down for a second. I find this really annoying. Either let the drift be settable or allow for a pause instead of reset option like the cobalt, or most others. There is nothing magical about 15 feet. Adding a little time for out of band would be fine too, but the reset thing is just irritating to me. I get the idea, I think the current safety stop implementation is at best a partial implementation of what should be a much more inclusive function set.

3. The hard time zero out at 700PSI. I don't like this and others have commented as well. Yes simple is good but, but this is over simplification. You don't collect enough tank info (size etc). This 700 psi time zero will mean something different every tank. If I want stupid simple, I will do the math myself. I really rather have the computer do the heavy lifting and not rely on just a add hock rule of thumb. Just my humble option on that approach. Frankly not a deal breaker for me, it just means I'm ignoring your reading and be diving my PSI and depth... I assume that will be normal so why bother having a untrusted data point on the screen. Perhaps I'm wrong but I think it's worth considering a change given the comments back on it overall.

4. Not always turning on.. twice now it has not turned on under water based on the pressure change. This needs some tuning, or maybe it's unit specific... I need more data of course. On the plus side if I turn it on under it dose the right thing and dose not force me out of the water to fix it . So nothing I'm that worried about.

So, please take this as constructive feedback from a customer rather then points or design choices that need to be defended. You really can't defend somthing that is annoying somebody who has to use the product anyway, it just serves to fuel the flames .

Patching and feature growth is good, and there is always room to improve and innovate no mater how solid a product launch you have.

I could just as easily written a love letter, but after a few dives, this what jumps out at me.
I won't start on the log software, other then to notes it's functional but feels pretty primitive and rough. Hopefully I can do direct import into divelog 5.0 soon.

Thanks
-Griffon

 

[scubafanatic]

Thanks for the candid observations! point # 2 would be uber annoying for me especially!

 

[TechDeep]

Very well said, I have about 30 dives logged on my Lynx, and I would agree with just about everything you say, ESPECIALLY the safety stop stuff, and the 700 psi. In rough seas, I tend to do a little deeper safety stop. And I agree, there is nothing magic about 15 ft. In fact, there is research that suggests 20 ft. (or at least a separate stop at 20 ft.) may be better. So I have lost use of air time remaining, and I time my safety stops separately. This should not be.

All that said, I still think it's a great computer, and I would think these things are things that could be fixed with firmware updates. I have not had an issue with mine turning on.

 

[Liquivision]

We appreciate all the feedback. However, if you want/expect real changes to be made, you will need to very specific in terms of what you want the new functionality to be. If you don't like the air time calculation method, you need to tell us what you think a more favorable version would be. Similarly with the safety stop. If you dip below the depth range, you don't want it to reset. So what if you ascend to 15ft, then descend again to 50ft and hang out there for 5 minutes? How long are you allowed to dip below the safety stop depth, and by how far? Once you start to really think about *every* possible permutation of actions a diver could take, it begins to be more clear why the Lynx software operates how it does. That said we are happy to make improvements, but only if the suggested improvements take into account all possible scenarios.

Regarding deep stops, you can easily get deep stops by running the computer in Tec mode. The higher you set conservatism in tec mode, the deeper/longer the first stop will be.

Remember REC mode is designed for NDL dives where you surface without deco (although it will of course give you a deco plan regardless). If you PLAN on going into deco and you expect deep stops, you would probably better off using TEC mode.

Eric Fattah
Liquivision Products

---------- Post added September 9th, 2013 at 05:14 PM ----------

Another note regarding the unit waking up: Firstly you should make sure you have 1.12 software installed which addressed a rare wake up delay issue. Second, if you choose to start the dive without turning the unit on, the unit can take up to 15 seconds to turn on.

Eric Fattah
Liquivision Products

 

[griffon]

The reality is that a consumer is going to compare the behavior to the other devices and review it as favorable or not in comparison without a deep analysis or code type perspective.

I thought I was pretty clear but ok:

1. I want to be able to quick, *tap* *tap* to the compass and back, left right screen toggle essentially. Ideal stretch feature set would be for divers to be able to define up to x number of views, order and toggle between apps/screens. i.e. screen 1 main view, screen two compass, screen 3 group view. This needing to move back through menus is annoying, particularly while at depth.

2. Deep stops (RGBM) has no correlation to deco obligation. I'm not sure understand what you are saying here or maybe you are not familiar with how most other modern comps have implemented deep stops? Common implementation is 1-2 minute non deco optional stops at quarter or half of total depths. I'm sure a lot of folks her can speak in more detail and greater expertise then me on this. Are saying this is the behavior in TEC mode if so great, I guess not sure why it would be separate since it's all non decompression diving. I'm looking at the manual now though and it's not clear to me how this specific behavior and interaction works for recommended stops? Deco obligation is spelled out nicely.

3. I want to be able to set a band range for my 3 minute safety stop. If I exit band for more then 1 (default) minute then reset stop counter otherwise pause and resume count. This would allow for safety stops to match conditions or known sites and dips if needed (like say when your buddy stops at 20 feet because his computer recommends a deep stop and you need to check that all is well if 5ft Monterrey vis). There is nothing magical about 15 feet but there is for 1ATM.. sorta.

4. I think there are ample examples of comps doing more of the heavy math lifting on time then the 700psi rule... I think the suggestion is more critical though not less needs to done here. Dose this rule hurt your competitive feature set? I would say yes, but not a deal breaker for me... just becomes ignorable errata. At say 5-8 feet in the shallows, am I really out of time at 700 psi? Of course not that is just silly. maybe I completed my safty stop at 900psi and I want the computer to be calculating and projecting my air usage time at while I play with the sand dabs... Zero? Again, I think the argument for simple breaks down there. Is my tank 2800 LP 80Cu or 3400 HP 120, 700 means something very different in each case. It's a compute, collect the data put it to work.

5. Not turning on: Thanks, I'll play with the timing. I just noted as I dropped down to around 20ft twice that it was off. I did not wait to see what it would do. Ideally it should be on already, but the auto sleep mode tends to assert between gear up and the time I can walk in when shore diving .

I beleive I have the most current firmware as of Aug. I will double check though. Should that happen again I will give it more time to adjust and see what happens.

We appreciate all the feedback. However, if you want/expect real changes to be made, you will need to very specific in terms of what you want the new functionality to be. If you don't like the air time calculation method, you need to tell us what you think a more favorable version would be. Similarly with the safety stop. If you dip below the depth range, you don't want it to reset. So what if you ascend to 15ft, then descend again to 50ft and hang out there for 5 minutes? How long are you allowed to dip below the safety stop depth, and by how far? Once you start to really think about *every* possible permutation of actions a diver could take, it begins to be more clear why the Lynx software operates how it does. That said we are happy to make improvements, but only if the suggested improvements take into account all possible scenarios.

Regarding deep stops, you can easily get deep stops by running the computer in Tec mode. The higher you set conservatism in tec mode, the deeper/longer the first stop will be.

Remember REC mode is designed for NDL dives where you surface without deco (although it will of course give you a deco plan regardless). If you PLAN on going into deco and you expect deep stops, you would probably better off using TEC mode.

Eric Fattah
Liquivision Products

---------- Post added September 9th, 2013 at 05:14 PM ----------

Another note regarding the unit waking up: Firstly you should make sure you have 1.12 software installed which addressed a rare wake up delay issue. Second, if you choose to start the dive without turning the unit on, the unit can take up to 15 seconds to turn on.

Eric Fattah
Liquivision Products

 

[RDRINK25]

I agree with the deep stops would love too see in Rec mode a stop at 40' for a min.

The one thing that I dislike he most is the safety stop. I usually try and hang at 17-18' but sometimes if looking out in the deep I drop to 21 and there went my stop. I agree that it pauses and will not reset till above 20 and if down for longer than 30 sec then reset.

One thing that I hope will change is in the buddy mode. I have a wife and a friend that both have a lynx but if we all go diving together we have an extra T1 on our screen. It becomes annoying and wish there was a 3 person mode or make the 4 person mode only show tanks that are on.

 

[mathauck0814]

Is there anything preventing you from doing a deep stop just because your computer doesn't prompt you for it?

 

[Akimbo]

…
1. I want to be able to quick, *tap* *tap* to the compass and back, left right screen toggle essentially….

I concur. A quick on/off toggle for the compass is important on small displays. The Atomic Cobalt does it with one of their four buttons. Granted you must learn that from the manual or experimenting but it is a small price to pay compared to a multi-level menu process.

…
Again, I think the argument for simple breaks down there. Is my tank 2800 LP 80Cu or 3400 HP 120, 700 means something very different in each case. It's a compute, collect the data put it to work. ….

Calculating gas time or alarm settings are useless unless cylinder size is part of the equation. Each gas needs cylinder volume.

 

[Liquivision]

Calculating gas time or alarm settings are useless unless cylinder size is part of the equation. Each gas needs cylinder volume.

Air time remaining can be easily calculated without cylinder volume. dP/dt is enough to compute air time remaining at the current depth; dP/dt plus current depth is enough to compute air time remaining at any other depth the diver may swim to.

Liquivision computers do not put in random deep stops. Deep stops were first introduced by Erik Baker's VPM algorithm (which eventually became VPM-B and RGBM). The Suunto and VR3 computers were not powerful enough to run real RGBM/VPM, so they began the practice of introducing a 'random' deep stop which was not necessarily called for. Liquivision computers (X1, Xeo, Kaon, Lynx) are powerful enough to run all common algorithms without guessing or approximations. If you run the X1 with VPM-B or the Xeo with RGBM (bubble models), they will calculate the true iterative model and produce any required deep stops as necessary. If you run ZHL-16 on the X1, Xeo, Kaon, or Lynx, then the gradient factor settings will control how deep the first stops show up, but only based on an actual requirement for the deep stop. The RGBM upgrade will also soon be available for the Lynx and Kaon. If you prefer to always stop for 1 minute at half your max depth you can easily do that on your own.

The original Lynx beta units had the full, extremely complicated air time remaining algorithm which attempted to calculate the air consumption during an entire ascent including assumed ascent speed, and deco stops. The beta testers rejected the algorithm as being too complicated, making too many assumptions that weren't necessarily true, and too difficult to understand what it was really doing. So we simplified it for the production launch.

An alternative method to modify the basic 700 PSI end point air time calculation would be to introduce varying end points based on depth. This would be quite simple, i.e. 30m-40m: 700 PSI end point, 20-30m: 500 PSI, 10-20m: 400 PSI, less than 10m 350 PSI. Or something like that.

Eric Fattah
Liquivision Products

 

[Akimbo]

Air time remaining can be easily calculated without cylinder volume. dP/dt is enough to compute air time remaining at the current depth; dP/dt plus current depth is enough to compute air time remaining at any other depth the diver may swim to…

Maybe, providing the tolerance of both pressure sensors are very high. The tolerance range of the air-time calculation becomes much narrower when the known floodable volume of the cylinder is introduced into the formula.

I must admit that I have very little confidence in air time calcs anyway. The depth and SAC rates are too variable.