Some clarification please. What is open exactly?

robertkarlsson

First of, hello all!
Sorry that my first post on these forums will be a bit negative. Here i go.

First when i read this i thought, wow, amazing. A real open rebreather project.

Imagine all the combined knowledge of the rebreather community building
and perfecting an rebreather. See the OSS community, eg Linux, BSD, Firefox, etc etc.

Then after reading around a bit i realised, ok the label "open" is missleading but the rebreather seems to be a nice and well thought piece. And since im currently looking to buy my first rebreather it was interesting enought to look into it further.

Then i read something about a built in function that allows disabling and unlocking features in the rebreather. So what this is, its basically DRM. That is you buy the product but dont really control it, It controls you.
What is next step? One have to reverse code engineer the firmware to actually remove those restrictions to actually have no restrictions?
DVD, DeCSS anyone ?

Control before freedom of choice, what i can and cant do ?
Shouldnt this choice be up to the diver himself?

So imho, the proper name should be Restricted Revolution Rebreather.

Shure there is allot of feedback between the engineers and people in here but what does that contribute in the end?
Lets say some people in here have really good ideas and presents them as an feature. Then it might get patented and that knowledge lost and locked in to the company that is owning the patent?
I don't want to get into politics to much its just that ive seen companies waving the patentflag to many times especially in the software world.
This is something for homebuilders to reconsider.

The whole idea with open is that anyone can see how it works, contribute to it and make it better. After each itteration it will be a better product then the previous (hopefully). A patent prevents this.

When it comes to the safety as stated on the DeepLife site:
"
1. Full disclosure of the FMECA
2. Full disclosure of the operation of the safety systems
3. Shown to protect the user all credible failure scenarios, including a list of conditions that have caused near misses and fatal incidents reported on rebreathers.
4. Shown to have a billion hours between Critical Failure.
"
I think its all good and i support it 100% as long as it doesnt interfere
with my freedom.

Maybe its not possible to apply an OSS like model to physical products, i dont know..

Sorry for ranting like this, i hope i'm wrong with this since i truly belive this is
a good product and have potential. I just got so very disapointed when reading about this when i got my hopes up at first.

DeepBlueInnovation

Hi Robert, and welcome to Rebreather World.

I think you have misunderstood the concept of the Open Revolution. The Open Revolution as I understand it is a mark of compliance with the points that you have listed. The deep life rebreather is a unit that is being created to adhere to these standards, it is not an open source project in the Linux model. The documents on the Deep Life website are part of the compliance requirements, with all the requirements being released before the rebreather is released to the public.

send Alex a pm and I am sure he will clarify things for you, although I suspect he will be tied up with DEMA for the next week or so.

It is also common practice to have levels of software available based on what you pay for - with many dive computers/rebreathers a base level of functionality is available with the initial purchase and users may pay to gain the unlock codes for further features. This keeps products affordable to users who are never going to use trimix features etc. It also provides manufacturers with an ongoing revenue stream

Cheers,

Ben.

AD_ward9

Thanks Ben, for a very good summary. DEMA was busy, and we are in a conference in Bergen this coming week too. Glad someone managed to post up pictures in the gallery here, as I have just been too busy to do it myself.

To answer the question posed by this thread:

What is Open is the entire safety case. It means Open safety. That means we publish the full test results for every aspect of the rebreather, the methods used exactly, their analysis and how the analysis has been carried out, the verification models themselves, the safety integrity assessment, the MTBF and MTBCF data, the circuit and hardware reviews, the full FMECA, the safety case, important HAZOPs.

The Revolution means compliance with the EN61508 safety standard, to SIL 4 in this case though units which are produced only in small numbers with good control over recall and upgrade would get away with SIL 3.

It refers to an Open Revolution in rebreather safety, not an Open release of a rebreather design for anyone to copy. However, key safety findings and algorithms created in the Open Revolution process have been published and we have stated that we are deliberately not patenting the most important of these in the hope others will take them up (some already have), and improve the safety in the whole industry.

Examples of things others have taken up already are:
1. Using twin injectors to check O2 cells continuously
2. Calibrating on air when the scrubber is open
3. No off switch: switching on with falling PPO2
4. PPO2 control algorithm

Cheers,

Alex

robertkarlsson

Hello again,

Thankyou Ben and Alex for clearing that out for me. I got a bit grumpy and when i look at it now it was almost a flame.
Just got my hopes up it was an real community driven open rebreather design free for all to use and implement. Sorry about that.

Even still, i think your work on the open rebreather contributes allot. The data that have been released is very valuable for us who are planing to make/modify our own rebreather some day.
All this information about sensors and solenoid / micro valves have been invaluable for me.
While on the topic, have you by any chance looked on zirconium based
sensors like for instance: http://www.sensortechnics.com/download/xya-637.pdf


Keep up the good work!

regards
Robert

AD_ward9

Yes, we have done a lot of work with Zirconia sensors.

The problems are they operate at high temperature internally, which takes power (a couple of amps) but also is highly dependent on the gas and pressure. Helium conducts heat so much better than air, and water even more so.

Another problem is because the sensing element is suspended on wires, to allow the element to heat up, it is very sensitive to shock. Drop a unit on the ground, and you get many hundreds of G force.

Alex

teksimple

Hey Robert -

I looked at the specs on that sensor and found a few things that would make it not really suitable for use underwater on a CCR. The 1.85 amps required to heat the sensor element to 700 degrees Celsius would require some serious power (like a car battery?) for any sort of dive duration. And then there is the insulation one would need to have between the loop internals and sensor to avoid melting important stuff. But don't let that discourage you. Necessity is the mother of invention, and there is plenty of innovation yet to come with regard to CCR's.

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"I don't know the percentage of the Internet that's valid, do you? Jesus, it's scary." - Hunter S. Thompson

onetime

Gotta say that when the subject was first brought up I thought the same thing. A community driven Rebreather project certainly had my interest.