Poseidon Releases Solid State Sensors

[RainPilot]

I just stopped at the Poseidon booth and spoke with Peter Andersson. There is no requirement to have them calibrated. There is a plan to be prepared to calibrate them if needed, but that is just a contingency

Tell him I say hi please! (Brendon)

Yup good point, same point was made on the InDepth article "Note: Poseidon sells the sensor for 6800SEK plus VAT from its website, which equates to 944 USD, some outlets in the states sell them for much higher"[1]



Thanks for the insight. I've read that they have an expected life of ">5 years"[2] and the InDEPTH article states: "As for how long the sensors actually last, even the manufacturers don’t yet know. Poseidon has some from 2014, and they still work but have to be factory calibrated every two years. Galvanic sensors need to be replaced annually, while solid state sensors are expected to last much longer."[1]

Do you have different instructions/information? Can you please provide it? TIA!

Sources:
[1] What Happened to Solid State Oxygen Sensors?
[2] PyroScience GmbH

That article was.....interesting. There are some inaccuracies/assumptions and biases in there (remember, it is published by an agency that advocates mCCR only and has historically had a cultural aversion to adopting new technology until long after everyone else has been on it). We (me and Poseidon folks) have had some giggles over it before. Similar to the (sometimes wilful) ignorance surrounding the cell validation that Poseidon does vs traditional voting logic, though that is a rant for another time.

Right now, the factory instructions are: Cell comes calibrated out the box. The calibration is guaranteed by the factory for ten years before the cell drift will reach an unacceptable level (forget exact numbers now but it's something in the magnitude of a 0.05 PPO2 error IIRC. Calibration can easily be checked if you have a CPOD by using it like an oxygen analyser, the Poseidon unit will also automatically check the reading vs the diluent content on start up and its simple to see if there is any deviation.) Buy cell, put in unit, dive for 10 years and before that happens the pathway to recalibration will be clear and simple (if needed).

The actual physical life of the hardware will depend a great deal on how you look after it (UV/storage/dropping it etc) but that is physical damage. The failure mode of these cells is such that, if it fits in the unit, and it gives any reading at all it will be the correct reading. Failure modes are all to zero data ie a cell fail indication. If you've physically damaged it (they are VERY robust) then it will just not power on.

I have a couple of dives on the very first original prototype sensors ( I actually have one sitting on my desk as I type) and they have been brutally treated by the factory test team, flooded, dropped, and generally abused. It is still rock solid, completely accurate to the limits of my ability to check against known gases and insanely responsive. We have taken them on some pretty serious dives and I would have zero hesitation taking it on a big dive as my only sensor. They have not needed any calibration yet, we aren't even seeing the level of drift the factory forecast to come up with the ten year number.

 

[rx7diver]

Poseidon announced at DEMA that they are releasing their exclusivity on the Solid State Oxygen Sensors (SSOS) which allows any other CCR manufacturers to put SSOSs into their units. Hopefully this will quickly make them options on most CCRs.

Solid State Oxygen Sensors! Who knew??!! A few days ago I watched a (recent?) YouTube video in which Jill Heinrich opined that the next challenge for CCR is solid state carbon dioxide sensors--which I thought was inspired insight! I didn't know that a solid state gas sensor of any kind was a thing!

rx7diver

 

[boriss]

Found this old video which might be of interest to people:

Lastly, here's another interesting read of a diver I've seen dive locally, who has been using solid state sensors for years: The Generic Breathing Machine: Front-Mounted Rebreather Innovation

Electronics​

The electronics has an interesting design. There are two sensor modules. One holds three sensors and the other holds one sensor. The configuration is two solid-state and two analog sensors.

Borodiansky has electronics that convert the two solid-state sensors, so a Shearwater computer can read them. The sensor modules are connected to the Shearwater computer with an AK4 four-pin cable designed for marine electronics. It is possible to disconnect and change computers without causing a flood.

Borodiansky has been diving and improving the GBM for the past several years. He has been diving the GBM on wrecks as deep as 100m (330ft) and using it in caves. Once he has the GBM certified by a training agency, it will be offered to the technical diving community.

 

[azstinger11]

Be curious to see how quickly shearwater and other CCR manufacturers support this. I would think there is some software differences that need to be taken into account on the shearwater side if these show up.

 

[RainPilot]

Be curious to see how quickly shearwater and other CCR manufacturers support this. I would think there is some software differences that need to be taken into account on the shearwater side if these show up.

Theres also the hardware, since the SSS signal has to be decoded from digital and then converted to analog, via some proprietary algorithms (which Poseidon is fine to release/license)

 

[GiraffeMarineSalvage]

I'm looking forward to seeing how adoption of solid state sensors goes, but I can't help but feel attempting to establish a new technology in a relatively niche application (relative to volumes of regular industrial/research/medical uses for sensors..) it's a business mistake to neutralize the potential promise of a long-term cost savings, instead of promoting faster adoption with 10 to 20% savings instead of what amounts to a need to pay up front for 10ish years of the operating costs associated with a tried and true technology (and new CCR divers still having to learn galvanic cell calibration anyway, at which point "might as well stick with what I already know...").

(Please note, I'm not disparaging a shift to solid state sensors in any way and from the little I know transitioning to solid state sensors will eventually prove superior to galvanic cells once all kinks and proprietary issues / standardization are worked out, from standpoint of long-term reliability (including ability to keep a backup sensor to protect against supply chain problems), I just hope solid state O2 (& CO2...) sensors can achieve the economies of scale/smart repurposing from other fields to let me rationalize personally upgrading ;-) )

 

[J-Vo]

Rumor on the board was that Shearwater was already testing with these. Maybe it's a software update for the Petrel 3, or there is an adapter on its way already. Nerd 3?

 

[-JD-]

Wouldn't the sensor interface be in the head?

Analog conversion or translation to DiveCAN.
Then connection to DC(s)/Controller/HUD over whatever cabling is used.

 

[tbone1004]

Solid State Oxygen Sensors! Who knew??!! A few days ago I watched a (recent?) YouTube video in which Jill Heinrich opined that the next challenge for CCR is solid state carbon dioxide sensors--which I thought was inspired insight! I didn't know that a solid state gas sensor of any kind was a thing!

rx7diver

Solid state sensors are already used for Helium measurement in the Divesoft analyzers and Liberty CCR

Be curious to see how quickly shearwater and other CCR manufacturers support this. I would think there is some software differences that need to be taken into account on the shearwater side if these show up.

These sensors are not made by Poseidon, they have a license agreement with the manufacturer Pyroscience in Germany

Theres also the hardware, since the SSS signal has to be decoded from digital and then converted to analog, via some proprietary algorithms (which Poseidon is fine to release/license)

Rumor on the board was that Shearwater was already testing with these. Maybe it's a software update for the Petrel 3, or there is an adapter on its way already. Nerd 3?

Wouldn't the sensor interface be in the head?

Analog conversion or translation to DiveCAN.
Then connection to DC(s)/Controller/HUD over whatever cabling is used.

The sensors are digital, use of any analog signal removes reliability of the system and would be avoided at all costs. Any sort of analog conversion would only be required if you used it with a non canbus based monitor device. Anything with DiveCAN has an oxygen board in the head that does analog to digital conversion. To convert a digital rebreather *doesn't have to be eCCR for reference* you would replace the oxygen board and then have a firmware update. The ideal way to convert older rebreathers is with an external pod like the O2ptima uses. This would hold the battery, OBOE if it is a DiveCAN implementation, and would power the sensors and be able to supply dual output. Incidentally the O2ptima will be one of the easiest units to convert because of this. I would be surprised if Shearwater supported these sensors with anything other than DiveCAN handsets.
It is possible that they could be powered by the handset like the old Predator controllers powered a solenoid but that would require a new board design for the Petrel and you would be changing batteries pretty often *like every time you change the scrubber type frequency*.

It wouldn't be difficult to build a board that powers the sensors and converts the signal to an analog mV output, there is nothing special about what they output and Pyroscience has all of that information published but you would have to design your own board to do it and again would largely defeat the benefits of an all digital system since the handset wouldn't be able to report any error codes that the sensors could throw which is the main advantage of a canbus system.

 

[TuckerIdaho]

Pyroscience sensor: PyroScience GmbH

It's not as simple as converting a digital signal to analog. The Pyroscience sensor is outputting O2% vs current sensors just output a voltage.