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Thread: New lifetime ox sensor by Poseidon

  1. #21
    Chett Lehrer Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L has much to be proud of Chett.L's Avatar
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    Re: New lifetime ox sensor by Poseidon

    Quote Originally Posted by silent running  View Original Post
    Funny, I've never had to bail out of my Prism 1. It can be dived with no high/battery current electronics at all, with the secondary PO2 needle gage display driven directly by sensor voltage and voting logic supplied by my brain. I've never missed a dive, so how is it that the most simple ECCR with 60 year old technology is more reliable than any Poseidon? Because given the current technologies, the more you shift responsibility for monitoring from the diver to the machine, the more technical difficulties you will have.
    If the SSS is so great, why is it an add on? Why don't they have a brand new model 8 with only SSSs? Seems like hyped up beta testing with customers. It's a weird move which does not seem to indicate confidence in what may be a significant innovation. I no understand...
    Hi Andy,

    Your right about the Prism Topaz. It may not have all the new flashy ginger bread stuff like the newer units, but it's a solid straight forward unit with thousands of trouble free hours of dive time without all the major issues.

    Best regards,
    Chett. L

  2. #22
    RBW Member whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot?'s Avatar
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    Re: New lifetime ox sensor by Poseidon

    Quote Originally Posted by deepwrecksc  View Original Post
    Do what you like - it is no skin off my back, obviously!

    The bottom line is that this is an excellent development for diving, and there is no doubt that fluorescence lifetime sensors are going to be far more reliable and long-lived than galvanic sensors. I'd love to have these in my rebreather, and I have no doubt that eventually it will happen. I'm excited that Poseidon has taken the initiative to make this technology into a product for diving.

    I've been paying attention to fluorescence quenching O2 measurement technology for a while... It has been a standard method for doing laboratory-based O2 measurements for quite a number of years. If you'd like to educate yourself on the technology, here is one commonly used product: https://oceanoptics.com/product/rede...nsing-patches/. One problem with applying this particular product directly to diving is that the sensor dyes that are most commonly used are TOO sensitive to oxygen! They are designed to measure really small partial pressures, and so at ppO2 above 1.0, the fluorescence is quenched to such an extent that there is practically no signal left to measure, and the data become extremely noisy. Fortunately, a few less-sensitive dyes have been reported in the literature, and I suspect that's how Poseidon proceeded with developing their sensor product.

    A few years ago, I "prototyped" a sensor like this in my lab, using a less sensitive O2-responsive dye I sourced from a colleague. It worked nicely at high ppO2, but there was certainly a noticeable decrease in fluorescence intensity of the dye over time as the sensor aged. There are two possible explanations: (1) the dye photobleaches - this is a known phenomenon, or (2) the higher ppO2 accelerates oxidation of the dye. Which of these is most responsible for the declining intensity is an interesting academic question, but it doesn't impact the practical result: the dye doesn't last forever. My comments about the projected longevity of this type of sensor are based on that experience. So - the decision is yours: you may trust the advice of a diving company manager, or you may listen to the experience of an analytical chemistry professor. I obviously have no stake in this - I simply hope to pass along information that is relevant.

    Rebreather divers are independently-minded, inquisitive, and often technically gifted people. For something as important to our well-being as an oxygen sensor, it behooves us all to understand both the advantages and the limitations of the underlying technology.
    Nice write up, agree 100% with you. When I fly I use a pulse oximeter at high altitudes. While the technology is a bit different, I think it essentially outlines the reason it's good to know what's going on when your body is in a potentially hypoxic environment.

  3. #23
    Mature mouth breather silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running's Avatar
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    Re: New lifetime ox sensor by Poseidon

    Quote Originally Posted by Chett.L  View Original Post
    Hi Andy,

    Your right about the Prism Topaz. It may not have all the new flashy ginger bread stuff like the newer units, but it's a solid straight forward unit with thousands of trouble free hours of dive time without all the major issues.

    Best regards,

    Yes Chett, thanks for saying so. For me, the main issue is simplicity which then begets reliability and maximum user interaction with our piece of life support. No matter how much technology we throw into the mix, the diver MUST always be involved in sustaining their own life. A machine tasked with monitoring and sustaining multiple crucial systems is simply incapable of caring for and about your life as much as you are..
    Last edited by silent running; 28th February 2018 at 18:39.

  4. #24
    RBW Member aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson is a jewel in the rough aknelson's Avatar
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    Re: New lifetime ox sensor by Poseidon

    Quote Originally Posted by Futura  View Original Post
    I was in contact to a Poseidon manager. He told me
    - the only limitation of sensor lifetime is the LED
    - the LED will work for 15'000 hours
    - the LED does not work all the diving time, it is flashing from time to time
    - therefor the LED will last much longer then 15'000 dive hours

    I do not doubt this.

    "Much longer then 15'000 dive hours" I still call this lifetime.

    Excellent comments about the SSS PO2 sensor
    The question remains why was the SSS sensor is not build with an Analog Output for a direct replacement of the current Galvanic sensor ?
    The power requirement is for sure an issue. Technically an Analog version will be less complex however service interfacing would be needed.
    The only advantage of the CAN bus is multiple data Points can be transmitted. One issue with the current M28 +SSS CPOD it is too expensive. 3.5k$ System cost sounds like a strategic price non related to the real product production cost. A well known Business "schemanigan" Andreas

  5. #25
    RBW Member EML is an unknown quantity at this point EML's Avatar
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    Re: New lifetime ox sensor by Poseidon

    It might be too simplistic but I think the reasons for developing this new technology on a digital bus rather than analog is because this is the trend on rebreathers. No one wants to develop something that is yet to be proven reliable on a technology that, slowly but constantly, all reb producers are abandoning.
    From a marketing stand point, it's a way for pushing people to replace their old rebreathers with new ones based on digital buses. And the remaining ones will sooner or later be targeted with some sort of digital-to-analog bridge that will allow their "old" technology electronics to read the new SS sensors.

    Regarding the high price, Poseidon has made an investment on development and research, for which they will be expecting a return. The production costs are just a fraction of the final price.

  6. #26
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    Re: New lifetime ox sensor by Poseidon

    the major problem for me is plumbing it into my loop; theres only one way to see if it really works and thats not on the internet.

    anyone figured out a set of adapters from draeger p port to this connection and back? that should allow older revo units to get this up and going right? just plug it into the inhale side and you get an extra computer to boot in the m28? or what am i missing here?
    Marv

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