Shearwater CanBUS board for making pressure pot?

[telemonster]

Hello all! I have a Prism2 and find it kind of a pain to do o2 flush at 20ft. I flush it but still question, did I flush good enough?

So I am thinking of building a pressure pot to test my cells.

Making a pressure pot, I need to read the cells. I could use a microcontroller and ADC, I could extend the wires from the pot to the CCR head and pass it through there...

ORRRRRRR

Since the Shearwater is CANBus, I know there is a little board in the head that has the ADC and pushes the values up to the Shearwater. Hopefully the Solenoid board is separate.

Anyone know what it's called? The price on it? That would be the sexiest way to connect a pressure pot with 3 cells to my Shearwater to read it.

 

[Mobulai]

Since the Shearwater is CANBus, I know there is a little board in the head that has the ADC and pushes the values up to the Shearwater. Hopefully the Solenoid board is separate.

Anyone know what it's called? The price on it? That would be the sexiest way to connect a pressure pot with 3 cells to my Shearwater to read it.

Do you mean the OBOE (oxygen board electronics)?
(That’s the “generic” name shearwater give it, you’ll have to check with Hollis users what they call it)

No idea if you can buy it on it’s own

 

[211ratsbud]

If you're just trying to read the cells, you only need multi meter some cable and a gland inside of your pot.

The SW electronics are not available separately and SW is adamant they do not support home builders. A stance they have not waivered on ever to my knowledge.

Prism is equally unlikely to sell you the parts.

 

[LFMarm]

Why don't you use the OBOE you already have and just make connection cables that go into the pressure vessel? There are some threads in the forum that describe how to do it.

 

[LFMarm]

Building The Under $50 O2 Cell Checker - wrecklessdiver.com

 

[LFMarm]

Thread 'Molex Connectors'

Dec 13, 2019

I'm building a little cell-checker pressure pot. As planned, it gives me the option of either using a separate black box with three 0-200 mV voltmeters or, using a different cable, plugging into the rebreather head and reading voltages on my handset.

Looking for a (hopefully) easy source for both male and female 3 pin molex connectors. There are six million options and I'm having particular difficult with the male side, which has the little polarity tab. I'd rather not buy them 1000 at a time and I'm getting crosseyed trying to sort through the options. If they were already wired...

• jgttrey
• Replies: 16
• Forum: Rebreather Diving

 

[telemonster]

I just thought it would be cool to be able to plug the 4 pin Shearwater handset connector into pressure pot and it just goes. To keep it super simple and compact. I would use less "captive" molex connectors versus the type in the head.

Yea, Shearwater won't sell the board. Got email from them, they suggested going Fischer for it. Lame. I'm sure if they did sell the little PCB it would be $2,000

Huge backlog of projects but probably would cost $25 in parts to "clone" the OBOE (just to read the cells and push it over CANBus.) I never got around to sniffing the bus, that was in another post. Maybe this is the encouragement to do so.

 

[sea_ledford]

Hello all! I have a Prism2 and find it kind of a pain to do o2 flush at 20ft. I flush it but still question, did I flush good enough?

So I am thinking of building a pressure pot to test my cells.

Making a pressure pot, I need to read the cells. I could use a microcontroller and ADC, I could extend the wires from the pot to the CCR head and pass it through there...

ORRRRRRR

Since the Shearwater is CANBus, I know there is a little board in the head that has the ADC and pushes the values up to the Shearwater. Hopefully the Solenoid board is separate.

Anyone know what it's called? The price on it? That would be the sexiest way to connect a pressure pot with 3 cells to my Shearwater to read it.

Pressure pot questions aside, are you trying to O2 flush at the beginning of the dive or the end? If you are trying to do it at the end, it is particularly difficult to get a pure O2 flush at 20 feet. I've never been able to get it up to 1.6.

If you are just verifying the cells will accurately read up to 1.6, you can spike during descent. I'll usually spike up to 1.6 -1.7 between 50-70', switch to high setpoint and dill flush back down to 1.2. That is usually just a single exhale out the nose and ADV takes care of the rest, unless you are really bombing down. And to clarify, this is a spike while I'm watching my controller, see the high Po2 warning, then immediately flush back down. I'm not chilling for minutes at a time at 1.7.

I know it is theoretically better to check linearity later in the dive, but I'm not going to spike high toward the end of a dive, and you are also fighting physics to bring the O2 up while ascending.

 

[Wheeler925]

I just thought it would be cool to be able to plug the 4 pin Shearwater handset connector into pressure pot and it just goes. To keep it super simple and compact. I would use less "captive" molex connectors versus the type in the head.

Yea, Shearwater won't sell the board. Got email from them, they suggested going Fischer for it. Lame. I'm sure if they did sell the little PCB it would be $2,000

Huge backlog of projects but probably would cost $25 in parts to "clone" the OBOE (just to read the cells and push it over CANBus.) I never got around to sniffing the bus, that was in another post. Maybe this is the encouragement to do so.

Computer engineer here that works with CAN daily.. this sounds fun!

 

[211ratsbud]

I just thought it would be cool to be able to plug the 4 pin Shearwater handset connector into pressure pot and it just goes. To keep it super simple and compact. I would use less "captive" molex connectors versus the type in the head.

Yea, Shearwater won't sell the board. Got email from them, they suggested going Fischer for it. Lame. I'm sure if they did sell the little PCB it would be $2,000

Huge backlog of projects but probably would cost $25 in parts to "clone" the OBOE (just to read the cells and push it over CANBus.) I never got around to sniffing the bus, that was in another post. Maybe this is the encouragement to do so.

There's stuff around to do this I just built a analog x dive can converter from components available in the custom builder forums.