Here is a video from the manufracturer of the CO2 Sensor Kit. Mine differs insofar I use a 1 ATA box and HUD: http://vimeo.com/31914685
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Here is a video from the manufracturer of the CO2 Sensor Kit. Mine differs insofar I use a 1 ATA box and HUD: http://vimeo.com/31914685
I have done some accuracy and linearity test and pressure tests of the unit finally assembled ready to dive. With 1% CO2 99%N (calibrated/certified bump test gas) the sensor reads 1.066% (quite accurate). Linearity so so, at surface the CO2 was 0.045% and at 90 meters the sensor read 0.612% (when it shoud have read 0.45%), which is still quite acceptable - BUT bear in mind the battery went low during the test and then it died while I was depressurising... so the linearity error maybe due to that as well. One thing I noted is that if the sensor and board are pressurised fast, at about 40 meters the board turns itself off as if the OFF button had been pushed (or maybe something else is causing this, but I think fast pressurization pushes the ON/OFF button and the unit turns itself OFF). In a a 1 ATA case no such porblem. I have posted a couple of pictures of the test unit final assembly with HUD ready for diving tomorrow and will upload overnight the test videos here: http://www.rebreathermallorca.com/forum/index.php?topic=100.msg219%3Bboardseen#new . Hopefully can make some videos tomorrow of the test dive with the display in clear view through the Lexan 1 ATA tube.
The CO2 Sensor performed well during the dive as well (cave, scooter, 60 min., max. depth 17 meters, distance 2.5 km., max. penetration 800 meters).
No false alarm and the reading was stable throughout the dive around 0.15% CO2 (off the top of my head) including during frequent and rapid ascents and descent.
If the video came out (no idea yet) it may be more precise.
Have you tested the sensor with trimix?Originally Posted by gianaameri
I did, but only in the pressure chamber, not diving. No problem in that test.
I learned something interesting the last couple of days diving the sensor.
It is essential to keep it off the rebreather until just before pre-dive and take it out the rebreather immediately post-dive.
If you don't, you prolongue the exposure to humidity, and if you leave it say overnight in the rebreather in storage in a very wet counterlung and loop the readings will drift up by as much as 40%.
After about 10 - 15 hours in air it will all return to normal, back to the original calibration.
It is really important NOT to re-calibrate CO2 sensors if they look off the mark because it may be just due to exposure to humidity, and it may correct itself given enough time.
I had constant reading of about 0.02% on the dive today (3.5 hours of scrubber use total) compared to 0.15% yesterday (same scrubber fill as today's), and yesterday the reading was high because I had left the CO2 sensor overnight in the rebreather (dry counterlung, but wet can and scrubber) and with the humidity it had drifted up a little.
I uploaded the full CO2 Sensor test dive video (2GB) here: http://www.rebreathermallorca.com/fo...=74.msg228#new
Been doing some longer dives (2 hours) and no problem whatsoever. The CO2 sensor was placed in the rebreather before pre-breathe and removed at the end of the dive. Max. CO2 was 0.05% (scrubber total use time 3.5 hours).
Nice to see that the CO2 Sensor I have been using is moving into commercial distribution in a nice 1 ATA case. Too bad the commercial version does not have an HUD.
See: http://vimeo.com/42380836
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