check the threads here: http://www.scubaboard.com/forums/ba...-co-tank-tester-choice-cheaper-than-rest.html
price point seems to make it appealing. Annual calibration and sensor life present indecision...
Building an O2 analyzer, anyone else need?
- Thread starter guruboy
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check the threads here: http://www.scubaboard.com/forums/ba...-co-tank-tester-choice-cheaper-than-rest.html
price point seems to make it appealing. Annual calibration and sensor life present indecision...
cbm32
Contributor
I would be interested in this AND the CO sensor if you come up with a way to make one of those as well. I would hope that once you make a few of these and gain enough credibility about delivery and no DOA's, that you would figure in a little something for your labor. A few probably woudnt take a LOT of time and might be fun but if it snowballs it may turn into a real chore to make a good number of them.
You have enough posts on here I am not real worried about you running off with my money. I know that I have offered to save people money on lodging with my timeshare points and have only had a couple of takers. I assume a good part of the reason that people choose to spend more than they have to on lodging is that scams are so plentiful out there. But, I think that anyone that is a long time regular poster in here is probably more trustworthy than the call I got today about having been chosen to receive a $7,000.00 grant from the Government if I just deposit $300.00 with them first LOL.
I would like to see a picture of one completed unit to see how it looks and have you report that it actually works before I buy a kit and have it sent to you. Is that reasonable?
You have enough posts on here I am not real worried about you running off with my money. I know that I have offered to save people money on lodging with my timeshare points and have only had a couple of takers. I assume a good part of the reason that people choose to spend more than they have to on lodging is that scams are so plentiful out there. But, I think that anyone that is a long time regular poster in here is probably more trustworthy than the call I got today about having been chosen to receive a $7,000.00 grant from the Government if I just deposit $300.00 with them first LOL.
I would like to see a picture of one completed unit to see how it looks and have you report that it actually works before I buy a kit and have it sent to you. Is that reasonable?
TONY CHANEY
Contributor
Very well stated Guruboy. Damn it is so hard to be nice these days due to the vast amount of media and crooks and crooks that get too much media. Right now I am thinking it over.
Now for the rest of the story. Nitrogen controlls the dive and not the O2. As for answering the question pertaining to MOD I will answer it with another question. Why are you even near your MOD in the first place? No one should ever plan a dive as to where the diver is a few feet from their MOD. P-6! (piss poor planning produces piss poor performance) I have kicked it around in my head and can only think of a few situations that present to be near your MOD. Not all but just a few are: 1) you are carring a stage, coming up from a dive and you are OOA or low on air and you want to or have to jump on your gas as fast as you can. (I would jump on it deeper than MOD if needed). 2) The only chance of saving someone from sure death is to go deeper than the MOD. (Not a choice anyone would want to face and that is one hell of a personal decision. So do you let your friend or love one die and save yourself or do you go past MOD and try to save them? If they die then you have to live with that for the rest of your life but if you die also then you have a bad situation as well as the recovery team bring back two bodies and two families suffer. No one can really answer that question until it really happens. I did it once and it was the hardest decision I have ever had to make in my life so far. OBTW, friend did not die nor did I). So again why are you even near your MOD in the first place? Chrpai you might want to start a thread on BM divers. This is just my take on the situation and I respect all other diver's input but I really do not think that it is going to sway my opinion.
Now for the rest of the story. Nitrogen controlls the dive and not the O2. As for answering the question pertaining to MOD I will answer it with another question. Why are you even near your MOD in the first place? No one should ever plan a dive as to where the diver is a few feet from their MOD. P-6! (piss poor planning produces piss poor performance) I have kicked it around in my head and can only think of a few situations that present to be near your MOD. Not all but just a few are: 1) you are carring a stage, coming up from a dive and you are OOA or low on air and you want to or have to jump on your gas as fast as you can. (I would jump on it deeper than MOD if needed). 2) The only chance of saving someone from sure death is to go deeper than the MOD. (Not a choice anyone would want to face and that is one hell of a personal decision. So do you let your friend or love one die and save yourself or do you go past MOD and try to save them? If they die then you have to live with that for the rest of your life but if you die also then you have a bad situation as well as the recovery team bring back two bodies and two families suffer. No one can really answer that question until it really happens. I did it once and it was the hardest decision I have ever had to make in my life so far. OBTW, friend did not die nor did I). So again why are you even near your MOD in the first place? Chrpai you might want to start a thread on BM divers. This is just my take on the situation and I respect all other diver's input but I really do not think that it is going to sway my opinion.
Personally i dont think there is any need to round down. Granted Nitrogen controls the dive so long as there is not an O2 issue in play. Here are my reasons why.
When using a dive table you always round depth up to determine your presure group. The fudge is now being made in favor of N2 loading. When dealing with Nitrox and the value of MOD. There is an emphasis to not exceed MOD rounding up makes a ever so sight buffer for PPO2 the same way that the NDL. With the advent of computer usage you cant do it both ways so one has to determine whether you are plannnin g to push the NDL or the PPO2 on the dive and then redetermine which is controlling that dive and round accordingly.
Does anyone know if the computer rounds. Ie... Is depth rounded to increments of say lower 10' for calculation purposes? If so the rounding down is already being done for the NDL side of the issue. In doing that it would be ballancing out the rounding up being done for the O2 side of things.
One more possibility. In air diving the computer rounds depth up to the nearest 10' . In nitrox diving the computer rounds depth down.
Just a thought.
When using a dive table you always round depth up to determine your presure group. The fudge is now being made in favor of N2 loading. When dealing with Nitrox and the value of MOD. There is an emphasis to not exceed MOD rounding up makes a ever so sight buffer for PPO2 the same way that the NDL. With the advent of computer usage you cant do it both ways so one has to determine whether you are plannnin g to push the NDL or the PPO2 on the dive and then redetermine which is controlling that dive and round accordingly.
Does anyone know if the computer rounds. Ie... Is depth rounded to increments of say lower 10' for calculation purposes? If so the rounding down is already being done for the NDL side of the issue. In doing that it would be ballancing out the rounding up being done for the O2 side of things.
One more possibility. In air diving the computer rounds depth up to the nearest 10' . In nitrox diving the computer rounds depth down.
Just a thought.
You beat me to it
NO. Controlling factor is Nitrogen.
Also, some dive computers factor in an extra 1% of O2 in the OTOX algorithm.
Alberto (aka eDiver)
Bull Excrement
Lets take an extreme case: 100 FSW with EAN32
EAD(EAN31) = (133*.69)/.79 - 33 = 83.1 FSW
EAD(EAN32) = (133*.68)/.79 - 33 = 81.5 FSW
EAD(EAN33) = (133*.67)/.79 - 33 = 79.8 FSW
Well within the 'close enough range for calculating your NDL
I said it in a previous post ... but probably you missed it.
Here extract from a manual of a dive computer (Cobra 3) manufactured by a very reputable company (Suunto):
"If set to the NITROX mode, the correct oxygen percentage of the gas in your cylinder must
always be entered into the computer to ensure correct nitrogen and oxygen calculations.
The dive computer adjusts its mathematical nitrogen and oxygen calculation models
accordingly. The dive computer will not accept fractional percentage values of oxygen
concentration. Do not round up fractional percentages. For example, 31.8% oxygen should
be entered as 31%. Rounding up will cause nitrogen percentages to be understated and
will affect decompression calculations. ...........As a safety precaution, the oxygen calculations in the computer are made with an oxygen percentage of 1% + set O2%."
But I guess you (and JohnN) know better
---------- Post added August 23rd, 2013 at 04:27 PM ----------
OMG .... a depth without a time doesn't mean anything
There we are. I believe the soundmness of the post the adding to the o2% compensates for the o2 reduction of rounding down for the benifit of NDL.
Given that,,,,and that being from a cobra 3,,,,, do other manufacturers follow the same logic, and what about non recreational models such as sherwater or other trimix computers when using them for nitrox?
Given that,,,,and that being from a cobra 3,,,,, do other manufacturers follow the same logic, and what about non recreational models such as sherwater or other trimix computers when using them for nitrox?
I said it in a previous post ... but probably you missed it.
Here extract from a manual of a dive computer (Cobra 3) manufactured by a very reputable company (Suunto):
"If set to the NITROX mode, the correct oxygen percentage of the gas in your cylinder must
always be entered into the computer to ensure correct nitrogen and oxygen calculations.
The dive computer adjusts its mathematical nitrogen and oxygen calculation models
accordingly. The dive computer will not accept fractional percentage values of oxygen
concentration. Do not round up fractional percentages. For example, 31.8% oxygen should
be entered as 31%. Rounding up will cause nitrogen percentages to be understated and
will affect decompression calculations. ...........As a safety precaution, the oxygen calculations in the computer are made with an oxygen percentage of 1% + set O2%."
But I guess you (and JohnN) know better
---------- Post added August 23rd, 2013 at 04:27 PM ----------
OMG .... a depth without a time doesn't mean anything
TONY CHANEY
Contributor
Well now that we have truly highjacked the thread, I put out a personal challenge for anyone to show me that rounding up is recommended in any book, instruction, etc. I bet that you will not find it. Please prove me wrong. You do not gain from the increse of oxygen but the decreased in nitrogen. Hint, hint that is why it is called the EAD or equivalent air depth or in better words the partial pressure of nitrogen in air compared to the partial pressure of nitrogen in nitrox. Also, why has no one given a reason as to why you are diving to ther MOD in the first place. JohnN please dont forget that you have to round up those depths. i.e. 81,82, etc has to rounded up to either 85 or 90 feet depending on the table used.
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I would have to look for my book but clearly when using tables you were always told to round up for depth round up for time to provide a margin of ndl safety or conservatism. In nitrox we always rounded up but that was for the context of not ndl but ppo2 mod o2 related problems ect.
---------- Post added August 24th, 2013 at 12:23 AM ----------
just think of what would happen if your puter was set for salt water instead.
---------- Post added August 24th, 2013 at 12:23 AM ----------
just think of what would happen if your puter was set for salt water instead.
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