Open source rebreathers - an alternative approach

uri

Remembering back to when that thread started and what happened to it, it strikes me that there was always an alternative approach to the concept. It just wasn't the one adopted.

I found the concept quite appealing but for me it meant a collection of standard components/bits that are available either in a manner that they can be easily fabricated or purchased. It was about enabling people to build/buy and assemble a known 'working' configuration based on the fact that someone else had already put the bits together in that particular way before and found it to work.

The Rebreather market is moving on apace and we are now at a stage when all the bits are available to start considering standard configurations of them.


The aim is to reduce the cost of entry for a diver to get a rebreather for people minded to take that approach. As such, I'm thinking of Kiss style units with potential for eccr upgrade if a method for easy upgrade can be found and suitable components sourced to do that.

Just a thought......


U.

onetime

I too was thinking along these lines when the original thread came out. Not just about putting together the commercially available rebreather specific bits into a unit but more a homebuilders uniting effort to take the ideas from everyone and transform them into a workable unit.

I'm all for it.

Genesis

I like it.

Each of us building has different areas that we think are "easy". For me its the electronic side. For others it would be a scrubber. For others it might be things like "T" pieces and counterlung options. For some its building a CMF injection system (e.g. KISSified valve)

Put all that together and......

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"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
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http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

uri

Indeed!

For me, a set of simple principles should provide easy guidance for decisions.
1: Off the shelf first if possible
2: As modular as possible (lots of nice rebreather scrubber cages about)
3: Aim for allowing as much choice and as much standardisation as possible
4: Aim for cheap as possible
5: Also aim for something that will meet the needs of most divers ie performant and easily transportable.
6: Low maintenance, robust, simple etc etc


Features and functions next.

U.

Yessic

Isn't this where ISC is going with the new Meg options?

Yessic

6Gill

I think it is a step in that direction however it should be possible to build an mccr for somewhat less.

Genesis

Let's see....
This means "available now", not "order it and when we make it we'll send one." When ISC can pack and ship a Meg (in your selected configuration) the day you order one, they'll meet this. When I mentioned this a year or so ago the response wasn't exactly cordial.
This one they probably meet with their "new focus."
So long as part of "choice" doesn't include "the only card required to buy it is a Visa, Master Card, Discover or American Express." For me (and most homebuilders), it does.
They're not even in the stadium - say much less the game - on this point. This one is arguably met, depending on what your definition of "most divers" is. Simple to many means "easy to fix and has immediately available parts, all of which can be sourced and changed out in the field without special expertise." Not sure how ISC measures up here... (demanding a $1500 add-class be taken before you can WORK ON your own unit doesn't seem to fit with that philosophy very well.)

2 out of 6 is an "F" in every school I've attended over my lifetime...

JMHO, of course.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

montyg

A great idea and also what I initially thought the "open source" rebreather would be about.

If we can agree on design and have a large number of parts made per production run and thus reduce the cost per unit?

I was thinking of starting with a part which is difficult and costly for the homebuilder since it almost always requires CMC milling which would be the "head" which is where the breathing hoses meet the counterlungs and/or the scrubber and it could have space for:
1. an ADV and/or
2. diluent injection
3. oxygen injection
4. 3 on-board cells
5. maybe accept one Drager P-cell holder for VR3 or HSE computer or OxyGauge

That way you could have a SCR or a CCR in an upright fashion and any size cylinders mounted vertocilly with bellows or 'ordinary' bag type counterlungs with the counterlungs above the scrubber or the scrubber above the counterlung(s) (like an EDO-04 or an EDO-08)

rgds
monty

Crazyduck

I am interested-

Estimated costs for me-
1. Hoses Vintage Scuba- $70 with cages and one way valves.
US distributor or Drager parts would be nice!
(Might have to buy Ray as parts donor estimated cost $900.00.)
2. DSV- Home Depot for now. (BOV- in development)
3. Scrubber case
A. IDA-71 (cheap)
B. Micropore conversion Est $340.00
C. Used Dolphin or existing scrubber (Ray donor for starters?)
D. Pasta container- $10.00 (need to add screens and spacers.)

4. MCCR o2 line into front of the scrubber-
Jetsam- est. $400.00 or Swagelok $100.00
Custom modification- for laser jewel in SS case- in development.

5. OTS manual add valves- o2 and Diluent- $125.00 drysuit add values each
6. OTS counterlungs- MSA waterbags 4 liter- $35.00 each
7. O2 sensors (estimated $90.00 each)
8. Two cell PPo2 monitor- PPO2.com estimated cost board and parts- $95.00
9. PPo2 monitor case (unknown yet.)
10. Mounting options-
Behind head (short loop) copied from go anywhere unit, current- optima.
Mount on backplate similar to other units with OTS counterlungs.
Chest mount like Dave Sutton- mini ccr.

Eventually-
Shearwater computer (est $1300.00) or deep thought ppo2 voting logic (est $600.00).
Cut down Radial Scrubber
Ali case
Purchase of 3rd party materials- either I can afford them or bump into them.
This does not include 1st stages, tanks, bailout, pressure gauges and lots more items.
This is basically taking 3rd party items and making your own unit.

Andrew

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Rob Davie April 2005-

Presently in a state of transition from Open Circuit to Closed Circuit.

"You will not be punished for your anger; you will be punished by it." - Buddha.

whoizrob

When I think about "open source" I think about all the different flavors of Unix and what they mean to their users. The different lines of thought regarding the term "open source" relate your percieved value of knowing the source. For some it means a good way of prototyping and debugging by the end user which creates a superior product. And to others open source means cutting away all the excess marketing and hype (and associated costs) from a name brand in exchange for a little research and sweat equity on the users end for a more accessible and affordable product.

So what do we expect from the open source rebreather project? I'd say Ad_ward has done a good job so far in that he has taken the former belief system and done well by it. He's prototyped a unit which meets many of current Rebreather divers needs, he's addressed many common faults in current designs and come up with what looks like a pretty darn cool product. Will it be cheap? Probably not. Can you whip up a clone in your garage? Unlikely. But is it successful using his design paradigm, most certainly.

Having said that I'd like to echo the thoughts of Uri and see a homebuilders open source project. I know that's a tall order since different end uses require different design paramenters (front mount, back mount, OTS Cl, Back mount CLs, one CL or two, cannister design, cannister orientation, blah blah blah). Regardless I figure an ED-series clone would be a great start. The standard plexi scrubber design has been beat to death and should be easy for most anyone to build. Most components can be integrated into the head (CMF orifice, ADV, and O2 sensors). The tricky part would be machining the head at a reasonable price point and that's been my favorite passtime for a while now; how to design a head which requires the least amount of machining but consolidates the various functions I want into that space, for the least cost, and with the least number of compromises. That's the hard part and why I have a day job which doesn't involve design or diving =)

So who want's to take a swing, eh?

We'd need a head design and a DSV shell. The DSV is pretty easy and You supply the ADV, hoses, CMF orfice, bypass, CL, tanks, regs, and blackplate. I'd say a great starting point has allready been made:

http://www.dykarna.nu/photoAlbum/alb...&albumId=10162

Rob

I'm willing to share some of my ideas I've sketched up but I'm terribly poor at AutoCAD. I'm more pencil and napkin minded Anyone have suggestions for a shareware userfriendly AutoCAD/Solids modeling prog I can play with?