Building a Better Mousetrap (O2 Analyzer)

[Padipro]

I haven't received them yet but it should be in the next few days. I'll let you know.

Scott

 

[Padipro]

I just received the sensors in the mail this morning and aside from having to remove a fixed resister from the circuit to get the adjustment to read within limits, these sensors are a differant brand then my old one, the reading from my analizer matched the reading from the shops analizer perfectly on all 4 of my tanks.

Does anyone know if storing the sensors in the refrigerator when not using them will extend their service life like it does with batteries?

Scott

 

[Genesis]

Even better is to insure you cover the sensor port so that no air can get to it. No O2, no reaction, sensor life is greatly extended.

 

[jamiei]

the shelf life expiration date is next month on the ones I see on ebay... should that be a concern???

 

[Padipro]

Shelf life is like the "Best when sold by" date you see on food at the store. It doesn't mean that it's bad after that date just that it's best if used by that date.

I bought three of these sensors. I opened the first one and tried it out just this morning, the output from the sensor was so strong that I had to actually remove one of the fixed resisters that I had installed inorder to use the brand new Teledyne sensor I had originally. I tried the trimmer pot in the circuit instead of the fixed resister in the begining but it never seemed to work. Like I said in my last post my analizer, with this sensor installed, read all 4 of my tanks exactly the the same as the dive shop did. Personally, I'm happy with it.

Genesis: I put the air tight cover on the brand new Teledyne sensor I bought from Maxtec less then 18 months ago and it's already dead, hence the reason I'm buying new one. I know that the cover is supposed to help extend the sensor life but I was wondering if the old frig trick, along with the cover, might work even better. Anyone know?

Scott

 

[NAM001]

there appears to be some concern about building your own o2 analyzer. i just built mine from a kit from oxycheq (el-cheapo2). works great. as with anything one must be aware of the accuracy's involved. i (from reading this thread) have learned that free air is not a good calibration source. i believe it also. thanks to those in the know for the insite. given that home made or bought has no difference in the results with all other factors being the same. as far as all other factors are concerned. i compare the results of the lds meter with mine. if they are the same all is good. what if they are different.... i use the high reading for o-toxisity and the low reading for nitrogen concerns. lastly if they are with in a couple of points +\- .3 does it really make a hoot so long as you are not pushing the envelope. look at all the rounding you do on a dive tables. for those that do push the envelope... your home made o2 sampler is not the primary concern of your potential self inflicted problems. i think my approach is a good check and ballance for the accuracey issue.

keeping it safe

 

[Stone]

Padipro once bubbled...
I know that the cover is supposed to help extend the sensor life but I was wondering if the old frig trick, along with the cover, might work even better. Anyone know?

I'm using the caps, also. Doesn't take long for the sensor to deplete the O2, so it is pretty obvious the chemical reaction is being reduced. I'm hoping for 3 years.

 

[jeepster0000]

Dmdalton said that you can use a volt/ohm meter and a sensor with some math to find the O2 percent. Is it a simple ratio formula or a big math problem? could someone tell me the formula if it is? I am in the process right now of building, but the volt meter will work for now.
Thanks
ADAM

 

[Padipro]

Hook your sensor up to a DVM and get a reading from a tank of straight air. Then devide by 20.9, the % of O2 in air, to find the % per mv for the sensor you're using. Then take a reading of 100% O2. The reading should be about 100X the original figure. It will most likely be a little off because sensors are not completely linear. Once you have the conversion factor established sample a mix and multiply the reading by the conversion factor you just figured out.

This info is straight out of the Oxy Hacker's Companion.

Scott

 

[canuckdiver]

another idea for saving o2 sensors.....

I was thinking the other night that a good method for storing your o2 sensors would be to take an air-tight case (pelican case, or even tupperware) and add two small fittings, one an LP inflator fitting, and the other and overpressure valve, then fill the container with an inret gas like helium or argon? This would keep the o2 from affecting either side of the fuel cell, correct?


just a thought...