Open source rebreathers - an alternative approach

heyydude

Can I throw something in here?

We have been supporting "homebuilders" with our stuff for years now.

We sell everything from electronic modules as an OEM, to complete Wrist Unit Assemblies with lengths of cable sticking out of them (we supply a wiring diagram for hooking them up).

There are literally dozens of homebuilders out there who have bought stuff from us this way.

I understand the nature of what everyone is trying to do - to come up with the magical $1000 eCCR, and maybe one day it will happen, but until that time comes, we ARE here to help those who want to build their own.

We've also counseled others on certain designs and methods for building their OWN commercial rigs (albeit, using our electronics). We do this as a service to serious companies and individuals.

I haven't been very good at tooting our horn lately, since we've been swamped with the Optima build - but this is something that should be common knowledge in the CCR community.

I believe we are unique in our support of the "common man".

Take care,

Kevin Juergensen
Juergensen Marine, Inc.

Genesis

If you can describe it I can model it in Alibre. I have a full license. They used to have (and may still have!) a freeware version - it has a few limits but none that prevent drawing - and you can send the files to someone like me who has the full version to do the final polishing. Or - give me mechanical specs or a "cheezy" drawing, I can model it, and we can iterate until you are happy. That's easy enough.

The scrubber and T-pieces are the two "gotchas" in most designs. The scrubber HEAD is not all that big of a deal, surprisingly enough. If you do a concentric-circle lid from two 1/2" pieces of Delrin, for example, you have something that will reliably seat in the tube, and you can then use a scooter-style crush O-ring as a seal and Nelson Sessions (scooter or can light) latches; the latter are available from Salvo Diving at a reasonable cost. That'll work just fine.

Mounting pieces (e.g. sensors, etc) into a head is pretty easy. The easiest is probably a clamp made from either plastic or stainless, screwed to the head. That's easy to fabricate with nothing more than hand tools and a Dremel at worst. So long as you don't need to "stack" components, its not difficult at all.

The issue becomes one of gas feed and extraction. If you're going to do a "all feeds from top" deal you need a center tube that is machined (but not necessarily CNC'd - an inexpensive lathe can make that piece easily from a stock piece of plastic pipe - you need only cut O-ring grooves and get a big enough die to thread the other end); if you feed from the opposite end (e.g. cross-shoulder scrubber or downtube aka Inspiration) then you don't need a center tube at all and its even easier.

The problem with the scrubber itself and the insert for it is one of material. Acrylic is somewhat problematic in that it isn't all that strong and has a nasty habit of shattering when abused. Polycarb is better, but hard to find in the proper sizes. HDPE is even better but damn hard to get - I've been working THAT issue with no success thus far; you CANNOT use gas pipe as it has a dye in the resin that is toxic; black water pipe will work IF you can find someone who well sell you a reasonable amount (they're happy to talk with you if you want a truckload! For one 8' piece its MUCH harder... no luck here on that one so far....) CPVC and PVC have a bad rap for offgassing - not sure if that's deserved or not, given that you CAN buy NSF-rated material. Of course the intended use there is LIQUID, not breathing gas transport... Oh, and all of these have potential "out of round" issues making it fun to insure that the scrubber insert (if you use an insert) seals properly. The solution to THAT may be to not use an insert and pack directly - still working this one through.

BTW, acrylic can be kinda expensive. A 12" piece of 8" OD (3/8" wall) is $163 from McMaster-Carr! If you go smaller (6-1/2" ID 7" OD) its much cheaper - $43. That might be more appropriate in terms of cost.... But... you have to put up with acrylic's problems, which I'd prefer not to.

I've got one piece of black HDPE pipe which is ok to use - but that's one piece. That doesn't help the NEXT guy though....

The T-pieces can be even more troublesome. You want a divider in the middle so that you get a good water-trap function out of them, and its non-trivial to accomplish. I can draw these up and have them machined to fit the MSR bags, but the price is more than a bit abusive. Injection molding is MUCH cheaper once you start talking about significant quantity buys - but prohibitive for small runs due to the mold costs. This one is tough and solving it goes a LONG way towards resolving one of the big issues with OTS lungs in a homebuild design. Its one of my personal sticking points right now.

Anyway.... these are where the "big issues" are from what I see...... then again, I have the 'leccies pretty much done..... its all mechanical now and these are the "big deals" I see ahead....

I appreciate the Hammerhead option but IMHO its just way out there in terms of cost. $3,000 for a controller? I understand recovering R&D and all that, but there sure isn't an economy argument to be made for doing it that way. If I wasn't good at that part of the equation I might see this differently, 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

whoizrob

Thanks for the offer. I found some shareware I will download to my home PC when I get home later tonight and see what I can't whip up. Most of the designs I have can be done on a simple home lathe like the Sherlines (my upcoming xmas present to myself!) and don't require too many cuts/bores done. The Kiss system is a pretty easy work around since you can buy industrial CMF orfices in metal for a few dollars and a bypass is easy enough to do using a dry suit add button.

I do understand that the T pieces are a serious issue to deal with and I wonder about bonding pieces of material together, but then you deal with issues of how strong the bond is and if there is any dangerous properties like off gasing to be considered. If bonding two pieces together is a possibility the issues of creating a T-piece becomes trivial.

In any case, research continues. I'll see what I can't whip up this weekend on the computer. In the meanwhile does anyone have any good material recommendations for a plastic which is cheap, easy to machine, and easily bondable?

Thanks,

Rob

RonMicjan

ahh, Karl, wasnt it a year ago that I suggested that you build your own and you said, "peice of cake" Still dont see it dude!! Its tougher than it looks, believe me. you sound like you are finding out that too with your difficulty in material requisition.

You can order any parts you like from ISC without a C card, try it and see!

Still no CCR company (save Jetsam) can ship the same day, and until Ford motor company starts building CCR's, I doubt you will. ISC makes every unit custom for the individual and as they have gotten faster and more efficient, the market has grown and now there are 20+ units going out per month, insead of 10, still the same backlog, sorry bout that.

If you designed and manufactured a life support system, would you just let any tom dick or harry work on it??? Or do a one day $50 course to learn maintainence on it?? Give me a break Karl, you know you wouldnt! The $1500 is a complete build course, to let the end user put together their own unit and is a bargin to anyone who values their equipment, what better way to really know how it works. As far as cheap goes, why would you want to buy the cheapest life support system you can find? I guess if you have a $10 head, then buy a $10 motorcycle helmet. ISC doesnt want to build the cheapest rebreather, they want to build the most value, most durability, and the most reliable units on the market and there they have a 4.0 grade point average. but thats just IMHO. If you cant afford the price of admission, then you cant be in the game. I started CCR diving on a budget and converted my SCR dolphin into the now almost famous CCR dolphin, after two years of diving on a budget, i stepped up to the plate and dropped my 10g's, and Im exceptionally happy that I did. In a year and a half, i have sat out only one dive from an equipment failure, I think that is a 3.9 GPA in any school I have been to.

So Karl, if you show up with your boat on the Oriskany in Nov, i guess we get to dive together, should I bring a CCR dolphin for you to play with??

take care buddy!

__________________

Genesis

Actually, Ron, it wasn't. I decided to build in December of '05. Eight months. I foreclosed buying an O2ptima (which made homebuilding my path to a CCR) roughly around the turn of the year, which was about when the stupidity with the PINs came up, if I recall correctly.

I believe I was told at the time "you'll never make any part of it work."

I intentionally took the entire summer off - from the first week of May until a couple of weeks ago - so I could travel with my daughter. The pleasures of being able to choose what one does... I'm not on anyone else's schedule here - just my own. As for November, I might make that. If not, that's ok. When its ready its ready. It'll get done.

I can order any parts I'd like from ISC? Really? Leon didn't seem to be all that interested the last time we had that discussion. If he WAS that interested, he'd have a price list up and an easy way to order - he doesn't. If/when he does, I'd certainly look at it for the fiddly bits like T pieces (and the bases that go in the C/Ls for them); it might be worth buying them.

As for being able to build them "to order", we talked about that too. If you truly have control of everything in-house and its all "which piece do you want which way" then what's the big deal about having the parts on the shelf? Stuff a box with the pieces and ship it. As I pointed out right here there's a hell of a cost difference between having FOUR boards made and having FIFTY made. Like a 500% difference (per unit) in cost. If you're too thinly-capitalized to have 50 made at once, what's that say about my risk of ending up with a paperweight?

Next there's the assembly thing. My argument has always been somewhat similar to the late Gordon's - if you can't build it up from pieces, you are not competent to use it. What goes hand-in-hand with this is that if a manufacturer can't provide an instruction manual with the product that allows a person of ordinary mechanical aptitude to assemble it correctly, then they screwed the pooch when they designed it. These things shouldn't be any harder to put together than the average coffee table - or TV stand.

As for the "Tom, Dick and Harry" argument, let's see.... I have FOUR "dangerous instrumentalities" (according to Florida law) on my property. Two are land vehicles and two are watercraft. I work on all four, including fuel systems (gasoline = boom if mishandled), brakes (crash!), electrical (damn its getting hot in here!), etc. My "formal training"? Zero. I bought the diag software for both my vehicles and watercraft on the open market, allowing me to see inside the "brain boxes" and make (potentially dangerous) adjustments. Nobody cared what card or class I produced - other than my AMEX. Ditto for my OC regs - I hold no cards or classes to rebuild those, nor to blend my own gas, nor to O2 clean things - but I do all of the above - and that stuff is life support gear by the "dive biznesses" definition. Obviously, I'm doing it correctly, as I'm not crispy, my garage is not burned to the ground or blown to bits and I haven't killed myself. Yeah, I know, its not the same. BS, says I, and I know we disagree. Never mind that I disagree with the entire "life support" canard in the first place; IMHO if that argument was valid you should have a PhD to be able to use any of this stuff. But - since you raise the same argument over and over, I'll rebut it yet again!

ISC wants to build Cadillacs? Cool. I want Cadillac service. ISC didn't sell me a unit because I couldn't "have it my way" - I didn't get Cadillac service.

It wasn't about the money - it was about the rest!

Ditto on the O2ptima.

All this oughta be obvious by now - hell, how many people go out and buy a lathe, a DSO, put a couple of months into code development and then start designing and ordering up CNC-machined plastics? If 'ya STILL think this is simply about the money I got a bridge for sale......

Now true, I like building things - its the engineer in me. And even after all this work Ron, I still think I'll be under the price of a "bought" unit - and will have the tools, and knowledge, to replace anything that breaks - myself. That's priceless. Of course Unit #2 will be a LOT cheaper, should I decide to make a second one......

BTW, I really - and I mean really - dislike companies that try to scare people into buying their products. Pulling out "if you have a $10 head then buy a $10 helmet" arguments is precisely that sort of thing.

Telling me that something I want is "impossible", or that I "won't be able to do it", is likewise a sucker play - at least historically.

We shall see how this all plays out eh?

One more thing.....

Remember not all that long ago Darlene ran into material porosity problems. At the time there was a comment made "oh yeah, we had that sort of thing happen too...."

That was a perfect illustration of the difference between cooperative development (aka "open source") and closed, proprietary competition.

In an open source model the first person who ran into this would have said something in public, and Darlene would not have taken the hit.

The value of open source development is the power of putting multiple efforts together in an additive format, instead of a competitive one. As just one example I happen to have a fully-licensed copy of Alibre Design; there's a free version at http://www.alibre.com/xpress/softwar...ign-xpress.asp, which will do a lot of the same things. If you draw a part in there, but need something you can't do in the freebie, I can do it and then send it back - or export it to whatever (e.g. a STEP file, IGS, etc) for you and send THAT back.

I stuck the open source code files on my web page, along with both schematics and PCB layouts, for precisely the same reason. Darlene, in her work, found a high side driver that looked promising; I looked at it and integrated THAT. She, for her part, may choose to use some of my design work if she likes it. Others may build on it as well.

You'll never - and I do mean never - get that power in a closed-design world. Microsoft has consistently lost badly in terms of "bang for the buck" against open-source - and they have more money than all the open source people combined - times 10. They claim to have the "best and brightest" developers too - but they can't offer a SECURE operating system, or one that doesn't require a gigabyte of RAM to run well. They lose precisely because they can't tap thousands of people who do something useful for them that gets integrated back into the original codebase - they're stuck doing it for money (salaries, being paid to write a driver, etc), and there's no openness involved. Just look at the security picture - 90+% of the world's e-commerce runs on BSD and Linux machines - that's where there's VALUE in a break-in, as you can steal things like credit card numbers 10,000 at a crack - yet 99%+ of all the viruses and attacks are against..... WINDOWS!

I see real power in a true open-source rebreather design. It could easily end up as exactly the sort of toolkit that FreeBSD or Linux is. Different people could offer up the various pieces - a scrubber here, a head there, a controller on this hand and a KISS-style valve on that. T-pieces from this guy and a DSV from that. You buy the pieces you want, assemble and test yourself, play with it until you're happy, and enjoy.

You think the $1,000 CCR is a "myth"? Malarkey. Entirely within reach under this paradigm. A $2,000 eCCR is not only within reach its likely a reasonable expectation. With open source you have a ZERO risk of having an orphan since the specifications - designs, drawings, PCB layouts, schematics and BOMs are all publically accessible. If "Joe" stops making scrubbers, you can bid out a production run of 10 - or 100 - and take over for him. No quarrels, no issues.

THIS is where I see the power of this sub-forum on the board. THIS is, IMHO, the goal - or should be anyway......

__________________
"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

RonMicjan

that wasnt me, I would never say that to anyone, cause you and i do share some traits, determination and skills, I said it would be harder than you think.
sweet man, good for you, I vacation a ton, have to or go crazy
Really, pick up the phone and tell him what you want, mail a check. Its not an advertised service because they make more money selling completed rigs instead of piddly orders for onesy twosey, i dont sell parts for my fill whips for the same reasons, its not worth my time to help someone else build what I build. but you can buy parts from ISC. hint:soon it will be easier

The parts are on the shelf karl, would you like me to take a picture next time Im there, I can and you will see anywhere from 50-500 of each item that is required to make a meg. building the thing takes time and leon is a perfectionist, not just anyone can work there and keep up the standard he demands. I dont know the exact number of man hours involved, but when I built mine (and I have worked with my hands and electronics all my life) it was quite time consuming, way more than I would have thought. Its all hand built, except circuit boards man.


This is great for guys like you, and I, but not the average diver, the skills to be an excellent diver are not necessarily the same skills to be a great technician. the meg is not difficult to build, just time consuming, I know really smart people who have no idea which end of the screwdriver wags and which end bites, can they dive well, sure.

You have not answered the question, this is not about you, its obvious to me that you could put your mind to anything and make it happen, I can too. Its about the average diver, who cant. Because you can fix your riding mower does not mean that joe average can be trusted to work on his own rebreather and how do you prove that you are different? You can pay the $1500 and take the course. And you still would not just let anyone work on YOUR invention, cause in this litigious society we live in all that dough you have from your old company would be sued away in no time. That is the point I am making, yes karl you are different, but you cant just stand up and scream "I AM DIFFERENT" cause that wont make any difference to the lawyers, and the company must protect itsself from the ones who scream but cant back it up with talent. 85% of people believe that they are in the top 10% when it comes to driver skill. who do you believe?

Right, I love to build stuff myself too and would rather build it than buy it, however, I dont have the equipment to build my own CCR from sratch, and if I did, it would be the same quality and robustness of the meg, thats why I chose that unit. Not to mention with trial and error, my version of the meg would have cost me 20k in materials for the same reasons you state, one offs are EXPENSIVE!

lets see, you, me, about a dozen others on this board

Not a chance, especially if you count your time, even at $5/hour.

The $10 helmet comment is to the ones that want a $1,000 rebreather, right now. sorry, if you want to dive CCR today, you need more money, maybe when the market is even 1% of all divers that would be possible, but not now. I am an early adoptor, my cell phone is $500, cause it does stuff most others cant, if everyone wanted the phone I have, it would be $50 cause the market is there to support the reduction in costs from MASS production. Its not, thats why ferrari only builds 100 detomaso's per year at some stupid dollar amount, if everyone wanted one, they would be lots cheaper.

Again, I would never tell you that something is impossible, just difficult. I have nothing but admiration for your skills, but what irks me is that you cant see that there is anyone else in the world but you, the rules were not made for guys like you, they were made for the idiots who need labels on their sleeping pills that say "may cause drowsiness" You really cant be that dense to see the reasons there are laws that protect stupid people. (actually I know that you just like to argue and discuss, obviously I do too, or I wouldnt be sitting here typin this ) Half of the population is of below average intelligence. Most people need a C card and the training that goes along with it, but half of these people dont think they need it. These are the boneheads that head into a cave with one light between three people and all on single tank gear, they THINK they know what they are doing and if you ask them they would tell you what an expert they are. My primary business is electronics installation in cars trucks boats etc. I even have trouble believing the crap I see that the average kid trys to do on his own car, 4 gauge wire run through the door jamb, stuffed into the battery post with no fuse, draped over the exaust manifold and a gas line and they say "whats the problem with that dude?" well, you f'n idiot, nothing until the heat from the exaust melts the isulation and the wire turns glowing red hot and then burns through the rubber fuel line turning your car into a burning pile of slag. I literally see this EVERY single day. do these people need a professional car stereo installer, YES, do they think they need one, NO, Does everyone, NO.

Same with scuba. So, we going diving in November buddy? PM me a phone number we should talk, I think it would be fun. At least come to DEMA, introduce yourself and I will show off a meg to ya, I think you would be impressed.

__________________

Genesis

Heh, I might come to DEMA. Gotta figure out how to get in tho. Or I might just come down to Orlando and screw around at the House of Mouse with the kid, and bring what I've got so people can look at it if there's an RBW party..... just gotta find out when and where that'd be, and of course there'd be a 10 year old in tow....

It might be a working unit, or it might be anywhere from working electronics (which is what I've got now) to a working unit.....

Diving in November? Sure. Will PM 'ya.... if not on the K1, hell, I'm not above tossing on a set of dubs. I do it now....

I still think the ISC model is broken. If it can't be assembled in 15 minutes by a monkey (e.g. the rough equivalent of a TV stand in complexity) then the design isn't up to commercial standards. That's IMHO, of course, but that's how I see it.

Yes, I know none of the existing commercial units meet that metric. That's part of my problem with them. Its not the whole issue, but its a part of it for sure.

I understand that not everyone can manage to make it work and do it themselves. But - you've seen my signature. I believe there are ways around the legal issues, and that figuring them out - rather than just throwing up your hands and playing along with a system that encourages the landsharks - is just as important as doing the design work properly in the first place. Yes, its harder, but reality is that it is also more secure, in the end. Hell, we live in a nation where you can take a cup that is labelled "Hot Coffee", put it between your legs, find out that it really is hot coffee, and successfully sue. In the process you can also manage to get excluded from testimony the proper brewing temperature for coffee (200 +/- 5F) - an inconvenient little fact that, if known, would make clear that scalding hot water is part and parcel of making a proper cup of Joe. But, of course, the jury heard all about other people who had scalded themselves and McDs "knew" the coffee was "too hot" - but not that there is simply no way to make a proper cup of the stuff without using scalding hot water! You now know, incidentally, why McDonalds' now makes a cup of coffee that tastes like crap, where before this little charade their coffee was actually quite good......

There is no way to win that war with any number of classes or certifications when the truth about something so simple as the proper brewing temperature of a pot of coffee is excluded from a product liability trial. So far its just been a matter of luck - luck that eventually MUST run out.

The only way to win that sort of game is to find ways to opt out of playing.

__________________
"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

jasondrake

"You really cant be that dense to see the reasons there are laws that protect stupid people."

Actually it would be really nice if there weren't. Might speed up the natural selection process. Instead of turning the masses into spoon-fed morons.

I suspect the solution to the liability issue will be to manufacture rebreathers in a country where sue-ing is impossible. Export them to whoever wants them and let them kill themselves if they please. Plus manufacturing in the 3rd world is cheap.

hmmm, I see a career change in my future...

uri

Wow, interest.

Lot's of opportunity areas and likeminded people.

I agree that the head is an area of difficulty with many options for flexibility/modularity. Let's get to that discussion.

I'd be inclined to hold for a little while on decisions about any specific bits of kit or capabilities until general agreement can be reached (if it can) in a few areas:

Start with the hopefully easy to agree bits

1:

Standard backplate and harness available from numerous sources cheaply.


2:

Standard scrubber cage available from a number of sources cheaply.

3:

Standard wings blah blah

4:

Standard Counterlungs. This bit's interesting and raises several questions. Do they exist? Can one get front and back mounted ones off the shelf? Do back mounted C'lungs raise issues with a standard harness/cage config?




Then of course there is the issue of 'standard' mounting positions and sizes/threads. In reality, does anyone know the interchangeability of the above components with each other? Does the Decoweenie frame mount with
the inspo counterlungs? Does the Kent Tooling Inspo frame mount with a standard backplate? What is a standard backplate? I'm sure that people on this list know answers to these questions and by pooling this, the result should be not only an interchangeability guide but a set of emerging 'standards' for people to build to such that they can support the market with compatible components.


The above limits nothing as far as I can see. Allows for complete purchase or mix of purchase and build and should be a good basis for anything that follows.

I'm grateful for Kevin and Ron for their input, i see no reason why existing suppliers can't add an enormous value to this potential market. It should be about choice.

Any thoughts?

U.

Duncan Price

Might I suggest that open-source rebreathers already exist. A number of homebuilders have put up detailed descriptions of their units including assembly instructions and where to obtain components.

DSV's and hoses are widely available from a variety of sources - Draeger Ray one's are pretty popular and there are are many DSV/BOV's to chose from.

Counterlungs are readily fabricated from water bags - though Inspiration ones have been used.

Scrubbers can be constricted quite easily (though this is probably the hardest part to anyone without access to a machine shop).

Gas addition via a KISS or needle valve for MCCR. Whilst the idea of an ECCR is attactive I guess that it adds an extra layer of complexity.

Gas monitoring via plug in meters.

See for example the Digspiration (on this board) or my D5 for documantation and what can be achieved.

The main issue is getting all the bits together in a cost/time effective way. As I like to point out, there is no point in re-inventing something unless you are keen to tinker otherwise you'd be been off buying a commercial unit. Probably the issue for a lot of homebuilders is that (for various reasons) they don't like the additional overhead of training and certification before they are let loose on a CCR.