Open source, I see problems. Questions.

silent running

Hello Alex, who said anything about the industry being open? I said that the Rebreather World forum is an open source and nobody on the forum seems to be keeping a lot of secrets. I was not speaking of the manufacturers who make our equipment. They don't tend to post on RBW too much. I fully agree that there needs to be more data available to us Rebreather buyers.-Andy

Genesis

"Open source" means just that - open source. I can use it, you can use it, anyone can use it. See FreeBSD or Linux for examples in the computer realm. This means published code and design down to the details, open, peer review, NO PATENTS OR PROPRIETARY CLAIMS (you can't have that review otherwise, nor can you claim ownership of someone else's contributed work!), and on and on.

Don't call it that if its not going to be that, or you will definitely raise the ire of those who really DO practice what they preach in that arena.

Second, I see a conflict here between design goals and implementation.

The design goal is a device that is so failsafe it requires no training to stay alive (indeed, that's one of the claims made in the PDF.) Yet there is then the ability for "anyone with the power" to shut it off, effectively, or restrict it.

Those two things are polar opposites, and you cannot serve both masters.

IF you truly have a design criteria and an implementation that is "fail safe" as a device, then there is no reason for it to be able to be turned off or for it to be "keyed"; indeed, there is no reason why anyone should have to buy training to use it whatsoever. (I speak of specialized training, not the basic physiological realities of diving itself.)

This is not to say that people couldn't buy it, just that they shouldn't be required to buy it.

Second, if I buy a thing, I own it. I will not buy a thing that isn't really mine. If someone else can shut it off at whim or will, then I have purchased nothing. That rings up as NO $ALE here.

You bring up other fields such as aircraft that refuse to allow accidental "controlled flight into terrain" as an example. Good point. But they do not disallow intentional "controlled flight into terrain" - if they did, then 9/11 couldn't have happened and of course it did. There's a difference and IMHO you have to draw the distinction in the right place. One protects from design flaws and external factors - the other is paternalistic to the point of giving offense.

Look at the design of an "intrinsically safe" device in any other field. Take something simple - a two-way radio for use in explosive atmospheres. It must not cause an explosion when used.

This does not mean that you cannot take a screwdriver, pry it open, and cause an explosion having intentionally violated its safety features, and the design of such a device does not preclude intentional misuse or abuse, and indeed, such a decision is one that a machine cannot make.

Let's take an example here. You are "competent" (in someone else's judgement) to go to 185 - that is, normoxic Trimix. You are on a wreck, and someone you are diving with takes their OC rig down to 210 and goes inside the wreck. They get lost. You know they're in there because of the exhaust bubbles, but your unit won't let you go get them. You happened to fill with 16/50, so you CAN go deeper, but your machine won't let you. It shuts off when you try to decend to assist.

He dies - because the unit refused to "let you exceed your formal training."

IMHO you can't have this both ways. Either the device is intrinsically safe or it is not. If it is, that still does not mean it cannot kill you by being abused.

Second example:

You fill the unit with 30/30 for diluent and go diving; you're qualified to 130. The water turns brown and you find yourself below the MOD of your diluent and bailout tank. The unit shuts itself off as beyond your training limit even though the mix in the loop is breathable so long as you do not flush, forcing you to bail out onto a mix that toxes you. You die because the so-called "intrinsically safe" rebreather killed you - on purpose.

IMHO you had a good goal - up until you put in the "big brother" stuff. Take that out of the spec, sell to anyone with the money to buy and develop this as truly open-source where "peer review" means anyone in the world can look, contribute and critique, and I'm wildly behind you.

AD_ward9

You refer to a specific pair of licences. This is not being issued with a Gnu type licence.

Open source here means it is published, fully exposed. It is not licensed under an Open Source Licence: the two are very different concepts.

Unfortunately the cost of development, and the absence of a large sponsor, such as IBM with a lot of Linux work, means we cannot offer an Open Source Licence, but that does not the sources being open. I chose lower case for the phrase.

If they restrict it, then it has put them onto open circuit.
You make a very good, and true point. It is just that the market is demanding that the user can override the safety systems current. We make it a pain to do so, and inform the user of the consequence using both voice annunciation and plain text.
No one is required to buy anything.
Who shuts it off at will? The user. That is, if the user goes outside the design limits of the system, the user´s action is shutting it off.
Some helicopter systems do prevent the pilot flying into fixed terrain, and some aircraft systems do prevent rates of climb outside design limits.
Intrinsic safety is quite a different topic. It does not mean the item is safe at all. It means it does not create sparks.
Similarly, any user can modify any equipment. In the case of the Open Revolution proposal, they would have to replace the electronics.
1. If you are at 185 and they are at 210 you are not diving together.

2. Simple solution: carry enough bail-out and us it.

He dies because he was diving solo and did not have enough gas to find his way out, or training not to get lost.
The meaning of intrinsically safe is a different one. It is actually intrinsically safe (it does not ignite the O2), but is probabistically fail safe: this does not mean you can use it for a purpose other than it is configured for. For example, diving a unit configured for 180ft down to 300ft.
It puts you onto open circuit in short bursts. You just need to rise a yard and you will be back on the loop.
Sorry to be so exacting, but Big Brother refers to being monitored, as per the book 1984. The equipment is not monitoring you (actually it is, but only you can read the monitor - the dive log). May I be so bold to suggest you mean "mothering".

If you don´t like equipment mothering you, just get the Expedition version. That has no limits at all. It goes until someone finds a limit. Their own or the equipment. The unit will not hit the market until it has been tested to some quite extreme limits - more later.

Cheers
Alex

PS (Edit): I thought about your point for a few hours. Let us keep things clear by avoiding use of "open source" and use "Completely Open Public Scrutiny" instead. You made a good point. Thanks.

Genesis

Linus Torvalds didn't have any "large sponsor" when he released Linux.

FreeBSD has no large sponsors at all, and never has.

I ran FreeBSD for years as the primary OS at my ISP, and still do as the primary OS that runs my home and business (literally runs, as in lights, HVAC, etc)

Neither of these codebases required "big sponsorship" yet both have hundreds of thousands if not millions of man-hours in their code, and a VERY active development effort. In the case of Linux the "big help" came later, in the case of FreeBSD, its been more-or-less intentionally snubbed.

Then you have OpenBSD, etc......
I see no reason for the unit to restrict the user's intentional decision-making. Making something failsafe does not require crossing the line into barring intentional acts.
Uh, you're not talking about the design limits of the system. The PDF talks about going outside artificial limits set by an instructor, not the unit's design limits.

Why? There's nothing wrong with the electronics. Its intentional crippling that I object to, not the design.

That's awfully simplistic and unrealistic. I will also suggest that in the US at least it brings the exact thing you're trying to avoid - potential liability - knocking on the door.

To argue that because someone has a problem they instantly become a "solo diver" ignores the reality that people DO get separated, they DO have problems, and that if you are on a device with a multiple-hour duration and the other guy is not you're in a position to do something about it.
Ah, but who says that this configuration limit exists? Its a function not of the unit's capabilities, but rather of an artificial hobbling that some third party has placed on the unit because of their view of how things should be.

As an example, what's wrong with diving 21/35 instead of "air"? Nothing. Indeed, I will argue that it is without debate SAFER if you intend to go below 100' or so, in that you have narcosis control. The MOD is exactly the same as it is with AIR for the same PO2.

So why would anyone sell a unit that is intentionally hobbled such that I can only use an Air diluent in it "officially"? That is, intentionally make me LESS safe when I dive rather than allow me, as the user, to choose the margin of narcosis management that I desire to use for a given dive.

If the goal is to promote maximum safety, wildly beyond what any rebreather offers now, then such intentional hobbling that introduces danger where none currently exists should be avoided.

I'm inside a wreck below the MOD of my DIL and bailout. If the unit forces me on OC it kills me. If I flush with DIL I die as well. But so long as I do not do either of those things, the loop's PO2 is breathable and I can rescue the stuck diver (assuming he still has gas; he can't breathe mine safely either!) by finding him with my guideline and allowing him to exit.

That terminology works for me.

The unit is not "mothering" me, an arbitrary third party is. The problem with this "mothering" is that it might get me killed, which is the polar opposite of the criteria under which the unit is being designed. In that sort of situation it may be a mother of a different sort.....

No problem....

But I see some problems here with the nice presentation and the claims made.

Among other things, Slide #3 claims that the cost of making the unit "737 plane-ride safe" is prety cheap. $300 or so? That's not much. So where's the big investment requirement?

Slide 17 is where I have my problem, specifically, the first six bullet points. Again, if I buy a thing, I own it. Get all the waivers you want, but whether you certify me to dive on 21/35 or not, if I decide I want more narcosis protection than I can get from an Air Dil, I'm going to run it. In this case if I don't have the fancy-dancy Trimix code to "un-hobble" the box when I load my 21/35 in the unit will refuse to let me get in the water, and if I try it anyway, it will intentionally blow up the CLs to prevent my descent.

Effectively, it will force me to dive narced - less safely - than I would like to.

I will not buy a device that intentionally prevents me from being safer in the water, and I would strong urge others not to as well!

The capability for an instructor to "lock out" the unit for any amount of time (including indefinitely!) basically means that you never REALLY own the unit, as it is, of course, of zero value as a rebreather if it is locked down.

If the unit indeed meets the criteria on Slide 16, point 5, then there is no reason to have an instructor lockout nor any "unlocking" codes.

In other words, if you meet that claimed design criteria then I should be able to order one of these things and decide for myself how, or if, I want to purchase training. As I have in my signature on another board "You want to see a C-card? Cool - choose from Visa, MasterCard, Discover or AMEX!"

IMHO you have to choose your master here - if you serve the diver's safety interests and truly meet the criteria you're claiming for the design on Slide 16, then you should be willing to sell a fully-unlocked unit to anyone, with no proof of training whatsoever, with the sole criteria for sale being possession of sufficient funds to make the purchase (and whatever waivers you want a purchaser to sign before taking delivery.)

If you get away from the paternalism I'd buy one. You'd truly have a unique product and quite frankly it would be a revolution - both in terms of what it is, and that you're confident enough in it that by design there is no special training requirement to live while using it.

This doesn't mean you shouldn't get training, but it does mean that you have faith in the device's basic design, and that my election of training now becomes entirely optional and under my complete control in terms of how, when, for how much money and by whom, rather than being forced by the marketers of the unit to a group of people who they "bless."

The design criteria I like a great deal, and recognize good things in it. But trying to serve both masters (divers AND agencies who will LOVE the keyed-lockup capability as a means to FORCE people to come back for Class 1 through Class "N", a potentially infinite list!) is, IMHO, a mistake.

divetheworld

I could not agree more with most of your argument, the rest of the technical arguments relating to the philosophy behind the concept, I could not give a toss. I can appreciate his position, and if the concept of completely fool-proof is able to be realised...........well, you dont need me to embellish that one. The problem is, I dont believe that it is possible right now, and the current generation of rebreather divers would resist such technology in favour of that which they are in control of.
Alex and I have had a lot of discussion over his design in the past, and I am of the opinion that if all the excess electronics and automatic this-and-that were removed then this truly would be a superb unit. To do away with all of the electrickery except the scrubber monitor would also bring it to the market much sooner rather than leaving a lot of it as "incomplete concepts" at this time.
The loop, scrubber format and especially the ADV design are innovative and well thought out. Get the setpoint controller going with the scrubber monitor and a simpler display and start making the package. The rest can be done as and when it is possible.

Brent.

__________________

AD_ward9

There is nothing stopping anyone donating their time and resources to create a rebreather with a Gnu type Open Source Licence. Just we do not have the resources to do such a thing: we design for our living, and to feed our families we have to charge for design work. Not just feed our families, but rent, rates, equipment (a single high speed scope is UKP100k, our EDA suites are over UKP1million).
It is about avoiding unnecessary waste of life.
If you are at 185 ft and your buddy is at 225ft, you are both diving solo. If you have a rebreather at 185ft and failed to plan properly so you have bailout to allow you to go 225ft, then your buddy will pay for the sum of the two mistakes: his and yours.
Nothing to stop you using 21/35.
Restricting the user to air dil is not one we had ever contemplated.
Restricting depth we do otherwise if you have a unit allowing someone to dive to 300ft without training, then they will do just that.
We will have to agree to disagree on this one. We just do not see that a unit that imposes a depth limit or a deco penalty limit by pushing the user momentarily onto Open Circuit introduces danger. The danger is providing a unit that makes it easy for any novice to swim to 400ft.
That is a statement about your diving style. I use a different style. You may laugh at my bail out, but if my Rebreather fails at 400ft inside wreck, I am returning and can do all my deco stops solo. The fact is, you should not need DIL at all once you are at your max depth. Why is losing DIL at your max going to kill you? If I did dive and lost DIL, and the unit pushed me to OC, I would just ascend and breath off the loop using the override, checking it is injecting O2.
Again, you are making a statement about your diving style. A style that this unit will not support. You need a manual unit.
So, you are saying a diver qualified to 180ft (ie not on trimix), is going to dive inside a wreck at 225ft to rescue a pal, but the diver at 180ft does not have any bail out. The unit stopping him doing that, or at least making him pause, is probably preventing a double death.
It does not say that. It says the additional cost of safety is $300 or so. Emphasis on the word "additional". The $300 addon is for a basic unit. Range is $250 to $700 extra cost depending on the starting point.

Yes, safety does cost money. At the moment all eCCRs use single microcontrollers. The microcontroller has an MTBF of between 60k and 100k hours, depending on type, and the oscillator and other components that drive it bring it to about 45k hours. If the oscillator stops, the displays probably look OK, but you have no O2 injected. No buzzer either. No vibrator. No change to the HUD. No life critical system should be designed that way, but all on the market are (except for a Meg, where there are 3 displays and 3 controllers I understand - there the failure points are different).

That is just one example.
It will not let you dive trimix unless you are trimix certified (and your instructor has enabled it for trimix on passing your course).
That is fine. Your choice. Everyone makes a choice. Any you also choose not to get the expedition unit, which does not have any of the limits you don´t like. Also your choice.

If there are enough people who want a cheap unit without limits, then there should be another Open Revolution proposal for such a unit. Just won´t come from us, at least not in the near future.
Your instructor is being paid by you. He is unlikely to be malicious. He is probably trying to help you and you are not listening.
There is still a requirement for training.
You have just met another breed: those who do not give up their principles for cash, no matter how much.
You might be right. If you are, market forces will no doubt create such a unit from some manufacturer.

What Open Revolution is all about is making public the safety systems, safety design processes and verification so we can all see the type of unit they create. I hope that in due course, all companies publish their verification results, test results, FMECAs and we do get safer equipment. No one design will satisfy all people.
Cheers

Alex

2stoned

I see a lot of good reasoning behind the computer/instructor induced limits.
Everybody is preaching: Do not dive beyond your training or capabilities.
By encouraging anything different a manufacturer may face liability claims later on.

The training required to dive other eCCR's are not any different.

The cowboy attitude is a major risk factor here.
Inform your diver body of your limitations.
Get trained and dive.
--

I would have liked to see the redundancy scheme taken one step further though.
4 cylinders:
Option of double (redundant) Oxygen and double or 2 different Dilluents, with pressure monitoring.

Since the computer already knows your consumption rate, it can tell you when its time to ascent.
(time left for CO2 absorbtion (compensated for depth),
When to change Dilluent or if BottomDil getting low to ascent to next Dilluent MOD.

With the current setup you will dive on your extras and later change to inboards.
The computer would currently go into alarms when you get low on your first set, or what?

This may seem excessive to some, double this , double that...
On a rebreather you bring very little, if you loose it you are in big trouble.

Everything is getting redundancy but the Oxygen supply?
Double cylinders, independent with each their own first stage coupled to a switchblock with opv's.
--

More expensive, yes!

Use more money to make your rebreather/diving safer, or
use more money on your life insurance.
-What ever makes you wife smile.
--

Looking forward to some hard info and pictures on the 4th rev of this rebreather.
A little more details on the computer('s) would be very nice as well.
Are the magnets in the swiches so strong that they would interfere with an analog compass?

Enough for now...

__________________
Sten.

The only man that always had all his work done by Friday, was Robinson Crusoe!

www.rebreatherworld.com - Is going down in silence - Staying longer in stealth and style - Diving first class, all the way!

Genesis

You are assuming that we planned that. I of course am not. I've been in the water when it has turned brown before, as I'm sure you have also. Fact is that people do get separated, they do dive different configurations, they do pair up and then be "less than perfect buddies." It happens.

There is a specific mention in the slides about "unauthorized mix" if I recall correctly. Since the unit as part of its start-up procedure senses the dil, I presumed you would do as many CCR manufacturers do and play the "first cert is air dil only" game. If I am incorrect in that assumption then I withdraw that objection.
I disagree. To dive to 300' without training I must first get ahold of a hypoxic dil fill. Unless I'm blending my own, that is going to be difficult. Nonetheless, as long as the original cert works off the MOD appropriate to a normoxic mix and the first-level restriction remains within that I'm willing to concede that this is rational even though I object on principle to paternalism.
Its not that easy. You first have to get your hands on appropriate diluent and bailout. Walk in a shop and ask for 8/60 and see what kind of eyebrows get raised......
Actually, I probably wouldn't - but that's ok. I'm talking about contingencies here, not the expected dive profile. I just believe that in extremis the person making the call on what is and is not acceptable risk should be the diver, not the unit.
So why not lock "on" the override?
No, I'm saying that a diver qualified to 180ft might very well be diving Trimix in his Dil tank (and should be if he has half a brain) but his bailout might not be breathable below 180. If he goes after the stuck guy at 225, and is forced onto OC, he dies. What kills him in that case is being forced onto OC as a consequence of the unit complaining about him being there.

If I choose to go after someone in that circumstance I am accepting that if the loop fails at that depth I'm in deep kimchee. What is not acceptable is the unit deciding to turn off the loop because it doesn't like me violating an arbitrary limit that someone on the surface set who isn't there to evaluate the circumstances that exist at that moment.
I understand that. As an engineer, I like the basics of your design. The only immediate flaw I can find is the use of a FPGA in both sides (FE and uP), unless the FPGAs are set up by completely disjoint groups and are different part numbers from different manufacturers. The idea here being to avoid a logic - or fab - error that could otherwise creep in.
You just got done telling me that you weren't going to prevent me from diving Trimix (21/35) on the base certification.

It didn't take long for that position to change.....

My personal view is that dives below 100', when rationally able to be done on a mix with helium in the tank, should be. I dive OC to 140ish in perfect conditions on a weak Nitrox mix, but what I'll do in 83F water with 100+' of vis and no current is vastly different than what I'll do in 40F water with 10' of vis and a screaming current.

I therefore strenuously object to a unit that refuses to allow me to dive normoxic (or hyperoxic) Trimix, as IMHO it is manifestly unsafe to force people onto Air diluent for any "real" dive.

The real argument for Nitrox (whether weak mixes or "Normoxic Nitrox", aka "Air") .vs. 21/35 on OC is about COST. That argument disappears on a Rebreather, since actual gas requirements are vanishingly small compared to OC. As such I believe there is simply no rational argument to be made against STARTING all new RB divers on 21/35 from the outset. Certainly eliminating narcosis as a concern is worthwhile, especially when it can be done at nearly-zero additional cost!
Ok. Fair enough.
Its not a question of malice. It is a question of who's life it is, and who has the right to pass judgement on the risk:reward of a given configuration. This is placed in stark relief when one compares Air diluent and 21/35 on a dive to 165'.

Arguing that I'm being "helped" by an instructor (or shop) who insists on me diving Air in that situation rather than 21/35 is rank hypocrisy. That instructor (or shop) is, in my opinion, criminally negligent.

(Note that I'm not arguing that I don't have a RIGHT to dive Air in that circumstance. Its my butt. I am only arguing that they are wrong to the extent that they prohibit me from using a safer gas.)
Your slideshow says there is not. What's "advisable" is not what's "required."
You may have just met someone who won't compromise his principles, no matter how attractive something might otherwise be. That road has two sides to it.
This is true (about one design satisfying all people.)

It will be interesting to see the product, if/when it actually shows up.

Please don't take these criticisms as "attacks" - they're not. I'm looking at the logic of the argument(s) presented, not the politics. To the extent that these issues are identified and your firm's position becomes clarified so that discontinuities in the claims and design are rectified, everyone wins. A prospective purchaser knows EXACTLY what he's getting, and you know exactly what you're selling. There is IMHO no bad that can come of that.

AD_ward9

I just said "there is nothing to stop you diving 21/35". It did not mention base level unit but I see from your thread, that was where you are coming from. To clarify, if you want to dive 21/35, you would need the trimix unit because the unit would detect the Helium. To overcome that, remove the scrubber stick (it unplugs with a few screws holding it in place as well). With the scrubber stick out, you lose CO2 sensing, scrubber life and health sensing, He sensing, scrubber replacement sensing, WOB/tidal volume/rr monitoring), but otherwise the unit still works fine.
By real dive, you mean I assume a deep dive. The unit will let you do what you want on a deep dive if you are qualified for that deep dive. It will not let an Open Water user nip down to 300ft, at least not without him thinking about it and going onto bail out. Nitrox should be the dil, rather than air for normal dives: 0 to 90ft type thing.
Controlling what you can do by trying to control the consumables/equipment is the way the industry works right now. To buy nitrox in the UK, or in the US, one normally has to show a suitable cert card. If the training agencies come up with some other forumula relating training to physical checks on what is supplied, we would do our best to support it. Until then, we support what they have or close to it. If you disagree with the cert cost route, then join BSAC (did I say that...?), where training is free - or almost free.
Bold statements: A lot of instructors do teach air as dil on CCRs. I would not use air as a dil now, though have done, simply because one cannot use it in SCR mode near the surface when you get plopped in in a current. If you do not like the philosophy of your instructor, then there are lots of other instructors you can choose from. The place to start is to convince the agencies to take up your position on trimix on day 1: none have so far so far as I am aware, but am open to be corrected on that one.
Hopefully we can keep clear of politics, and I hope the position we are taking is clarified.

Interesting that user "Genesis" is debating the issues with Revolution: perhaps it should be "Revelations"!
Cheers
Alex

Genesis

ROFL!

I do not disagree that the various agencies all think you should "start with air" (whether on OC or CC)

But I disagree with that premise, unless one never dives below 60', in which case the benefits of a mix without He in it are far more difficult to find (with the possible exception of WOB issues in a strong current)

IMHO there should be no restrictions on 21/35 that are not present on compressed air. If you look at the profiles for virtually any "sport dive", you will find that you can actually dive 21/35 on an air table and be fine. Indeed, you'll actually be more conservative on an OC dive if you do that and go to EANx50 for your deco, but use an air table according to modern (e.g. VPM-B) bubble models.

I have a strong dislike of politics in the diving "industry", as you've probably figured out by now. That dislike gets pretty extreme and vociferous when it turns into endangering people with completely unsupportable positions that, to me, look like nothing more than a way to force people to do dangerous things before they can do safer things (all in relative terms, of course.)

We currently have a carrier (the Oriskany that in theory is going to be sunk as an artificial reef sometime early next year. It will lie in 210' of water with the tower coming to within 60' of the surface. The flight deck will be at roughly 130, hanger deck at 150-155, and of course inside will vary all the way down to the sand plus probably 10-20, depending on how far it buries itself in the seabed when it sinks.

I expect that the "you can't buy 21/35 without a Trimix card" game is going to be a material contributor to a significant number of deaths on this wreck, and it angers me that this situation is both completely avoidable and that those who scream the loudest about Nitrogen-based gases being unsafe below 100' aren't ALSO issuing cards at the OW level allowing the use of 21/35 - a gas with the same MOD as air, but infini