CO2 sensor design

Brad_Horn

Chett,

From the FAQ, looks like the full data release will occur 22 Sept.
CO2 monitoring: CO2 capabilities are much more extensive than a simple break-through monitor. Details will be in the datasheet published in September, including the manual.
Monitor PPo2 Display: The PPO2 and PPCO2 is displayed on the PFD (a.k.a. HUD), and when the user hits a button on the PFD it gives the value through voice annunciation. If the PPO2 is outside the normal range, it gives the voice automatically. The levels are shown on the buddy display (a colour OLED) all the time the system is in use. The system is modular, comprising the Rebreather monitor and PFD as one assembly, with tank senders and an optional dive computer as add-ons. The dive computer shows PPO2 and PPCO2 values as well as the other Rebreather status information, and the usual deco, gas and profile information. All comms with the dive computer are by RF. When the product is released, so will the circuits, software sources and safety data, in line with the Open Revolution ideals.

The DAN Tech Conference .mp4's/DVD also shows a USN CO2 testing setup, which IIRC is some the technology in the Sentinal.

Regards
Brad

Chett.L

Yes, I think the unit is 1000, then you spend a couple more to get there electronics. It is probably going to be 3 to 4 thousand total USD FOB Scotland.

I notice that when you go to the home page at Deep Life Ltd: Specialists in life critical system design Then go to Revision History. Then go to Sports FAQ, it really show you a lot. This is a comprehensive web site.

__________________
Chett. L

Bruces

I was working on a CO2 monitor yesterday, it was out of a biological incubator.
It used a heat source (ceramic potted) 5 volts drew about 1.2 Amps!...the sensor was 0 to 10% CO2 with a 0 to 1 volt output. The tricky/ expensive bit is the spectral filter which has to be setup to only transmit a narrow band of IR thats is attenuated by the level of CO2. Can it be done in a rebreather? of course. The replacement part for our incubator was quoted at $1860 aus!...we are hoping to find the IR sensor from a 3rd party supplier and see if we can save a few bucks...will advise further when I can. Bruce Stewart

Gary68

Did anyone already suggest CO2 absorbtion in water and pH meter? Isn't that what the human body uses to decide when to breathe?

Sorry if this idea has already been shot down.

teddy2005

there's a"buzz" around here that v4tec (Germany) is currently developing a sensor with HUD display. Don't know more on this but will revert if there are some confirmed news.

BTW, I wonder, reading some posts on CO2 hits and the very short time you have to react, if the sensor, if any, will be able to warn timely so one can take appropriate steps to avoid real problems.

regards

deepwrecksc

I mentioned that as a possibility in the first post but then didn't really follow it up. This sensor: http://www.microelectrodes.com/Products/MI_720.htm is designed for liquid samples (fully immersible) but it also works with gases. It would be worth a shot to see how it responds under hyperbaric conditions. You'd have to do some temperature compensation but that isn't insurmountable.

Lee

Chett.L

Brad,

How many systems are out on the market that really work right now and what are there names?
Has Tom Rose, developed system or is still working on one? I just heard that Liquivison X-1 has a unit for monitoring C02 capabilities that there working on.

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Chett. L

Brad_Horn

Chett,

The only systems that I am aware of that that are known working for Co2 monitoring are by:
- HSM Technologies as fitted to the Infinito (unobtainable?)
- What NEDU developed for Co2 trials (some aspects of this in the Sentinal?)
- DeepLife Bell Diver's Rebreather (EURO 50k) (available now)
- Deeplife designed Apocalypse Type IV (US$995) with the Co2 capability in the Rebreather monitor (EURO 995) available to order from 22 Oct 08 DEMA.

So at this point in time as far as I have come across the Deeplife designed mCCR will be the ONLY unit that you can order from DEMA and KNOW it has been fully tested for use as part of an underwater life support system.

- X1 is a display only, no CO2 sensor.
- Bobby mentions a Co2 sensor going through contracting with an undisclosed Rebreather company, ISC, Hollis, Cis-Lunar? {Is it a concept or fully scientifically and independently tested Co2 system ready for sale as a plug & play component} Unknown timeline
- V4tec Details unknown, Unknown timeline
- Tom Rose, havn't seen anything recently regarding Co2 sensor's.

Alex Deas has written a lot on RBW about Co2 sensor's, it 'seems' as though getting one to work in a rebreather (on the surface anyway) is 'easily' doable until you add Helium and limited power supplies to the equation, let alone use it underwater.

Time will tell, looks like next month @ DEMA will be fascinating for rebreather diver's as the next generation unit's become available.

Regards
Brad