Poseidon Releases Solid State Sensors

[tbone1004]

Money aside, I think direct support by a Shearwater handsets would be better. I have a feeling they will only support on the canbus though.

Well from a technical perspective the only way they can support it directly is on the DiveCAN, so that is literally the only option for them to support it directly. Since they've come out several times publicly saying they will not support DIY upgrades or homebuilt units then the only option for a KISS to get official support for these cells is for them to implement DiveCAN. Doesn't mean they have to go to eCCR, but they would have to implement DiveCAN and there is no room in the heads for them to do that without an external canister like the O2ptimas and I doubt that will happen any time soon. More importantly, since they have said they won't support DIY upgrades or homebuilds, then it's up to the manufacturers to demand it for them to implement. I know they have had these cells for many years and know how to talk to them, but it's on the rebreather manufacturers themselves to implement....

 

[telemonster]

Neat sensors! Seems similar to other ones that have existed.

Looking at the command protocol it's basically 19200bps serial on a 3.3v serial bus. Doesn't seem ideal versus SPI or I2C. Could easily find a microcontroller that supports 2 or 3 uarts, the ability to read the DC battery voltage and talk CAN. Then you could convert these to run on a Shearwater controller that talks CANBUS. The protocol to talk to the sensors is well documented, the Shearwater CANBUS stuff isn't. I was starting to take a look at it. Downside is hard to mix say two Analog sensors and one digital without building the analog side again.

I think on my Prism2 the handset powers the board that reads the o2 cells for the handset, so that would bring power issues into play since higher power draw as previously stated.

Also from the datasheet:
"Do not use these products in safety critical devices or in any other application where
failure of the product could result in loss of life, personal injury, or damaged property.

This device and the sensors are not intended for aerospace, medical, breath monitoring,
diving, military or other safety-relevant applications.:"

 

[Whitrzac]

The cya warnings...

 

[RedSeaDiver2]

Neat sensors! Seems similar to other ones that have existed.

Looking at the command protocol it's basically 19200bps serial on a 3.3v serial bus. Doesn't seem ideal versus SPI or I2C. Could easily find a microcontroller that supports 2 or 3 uarts, the ability to read the DC battery voltage and talk CAN. Then you could convert these to run on a Shearwater controller that talks CANBUS. The protocol to talk to the sensors is well documented, the Shearwater CANBUS stuff isn't. I was starting to take a look at it. Downside is hard to mix say two Analog sensors and one digital without building the analog side again.

I think on my Prism2 the handset powers the board that reads the o2 cells for the handset, so that would bring power issues into play since higher power draw as previously stated.

Also from the datasheet:
"Do not use these products in safety critical devices or in any other application where
failure of the product could result in loss of life, personal injury, or damaged property.

This device and the sensors are not intended for aerospace, medical, breath monitoring,
diving, military or other safety-relevant applications.:"

Would seem a bit odd that Poseidon would use them in their rebreathers...

 

[RainPilot]

I suspect thats the data sheet for the sensors that Poseidon used a the base for theirs. They took the solid state sensors and worked with the manufacturer for a few years spending a LOT of money getting them suitable for CCR use, including the waterproofing, humidity proofing etc etc. That was the exclusive license Poseidon held, the use of these sensors in diving applications.

Very similar to most galvanic sensor manufacturers really. Started life as dry sensors in industry then got adapted to CCR use.

 

[tbone1004]

I suspect thats the data sheet for the sensors that Poseidon used a the base for theirs. They took the solid state sensors and worked with the manufacturer for a few years spending a LOT of money getting them suitable for CCR use, including the waterproofing, humidity proofing etc etc. That was the exclusive license Poseidon held, the use of these sensors in diving applications.

Very similar to most galvanic sensor manufacturers really. Started life as dry sensors in industry then got adapted to CCR use.

they spent a lot less money with the manufacturer than you may think, they were already pretty bulletproof from industrial use when Poseidon got around to it. They did a few things to them but it's not nearly as much as they'd like you to believe

 

[TuckerIdaho]

they spent a lot less money with the manufacturer than you may think, they were already pretty bulletproof from industrial use when Poseidon got around to it. They did a few things to them but it's not nearly as much as they'd like you to believe

According to other folks, it's a straight off the shelf from pyroscience sensor with a different firmware. It's been around for a while.

 

[SavageSeaCow]

Anyone have real world experience with these sensors yet? I’m thinking about trying to use a four pin box on the rEvo to replace two of my galvanic cells that read out to my back up petrel. I sent Martin a message to see what he recommends. I’m thinking the biggest benefit would be to validate the controller O2 cells with a “source of truth” when doing the pre dive calibration. And of course to have a better sanity test for when a cell decides to act up on a dive. I look forward to the brave new world in which the divecan Nerd can read two cells directly and I can stop swapping cells when I start to suspect they’re getting sketchy. I can see a value in having a third for comfort in a cell house on the inhale side of the loop for complete redundancy and physical distance in the off chance of a flood.

 

[beldridg]

I look forward to the brave new world in which the divecan Nerd can read two cells directly

I'm not sure what you mean by this?

Can you explain your rEvo setup a little further? I.e., is the NERD a controller on a Divecan bus with three cells and the Petrel is hard-wired into two different cells on a 4-pin connector?

I'm just not sure what you mean by "read directly?"

Regards,

- brett

 

[SavageSeaCow]

I'm not sure what you mean by this?

Can you explain your rEvo setup a little further? I.e., is the NERD a controller on a Divecan bus with three cells and the Petrel is hard-wired into two different cells on a 4-pin connector?

I'm just not sure what you mean by "read directly?"

Regards,

- brett

Yeah the controller is three cells on a five pin DiveCan connection. Since it is a digital connection there must already be an analog to digital conversion. The petrel is connected to two cells with a four pin AK.