Scuba Equations

[Poggus]

Hi.. I wasn't really sure where to post this topic, but here it goes.

I'm a Computer Science major and for my final project this year I'm making a sort of interactive Dive Log/Dive Planner. Even though the typical computer can do all of these calculations, it's an opportunity to combine programming and scuba. When I took my Nitrox course, I like how the last chapter in the book reviewed equations for calculating Equivalent Air Depth, Contingency Depth, etc. With these equations I can have my program manually determine certain variables without having to refer to Dive Tables.

So my question is: Are there equations for determining Pressure Groups and Surface Intervals for the Recreational Dive Planner? Or am I going to have to enter the entire RDP into a database for my program to refer to? Hopefully this question makes sense... I can clarify if it does not. Thanks!

 

[DiveNav]

Hi.. I wasn't really sure where to post this topic, but here it goes.

I'm a Computer Science major and for my final project this year I'm making a sort of interactive Dive Log/Dive Planner. Even though the typical computer can do all of these calculations, it's an opportunity to combine programming and scuba. When I took my Nitrox course, I like how the last chapter in the book reviewed equations for calculating Equivalent Air Depth, Contingency Depth, etc. With these equations I can have my program manually determine certain variables without having to refer to Dive Tables.

So my question is: Are there equations for determining Pressure Groups and Surface Intervals for the Recreational Dive Planner? Or am I going to have to enter the entire RDP into a database for my program to refer to? Hopefully this question makes sense... I can clarify if it does not. Thanks!

Why do you want to simulate the tables while you could simulate a decompression algorithm itself?

Alberto

 

[BCress]

I'm sure there are equations, (how do you think the guys who made the RDP got thier numbers! ) You may just have to so some google searching and long nights guess-and-checking. I doubt the guys who made the RDP would give up their equations, Because now you're just competition . Good luck and I look forward to the final product.

 

[BCress]

why do you want to simulate the tables while you could simulate a decompression algorithm itself?

^^^^^ true that^^^^^

 

[ItsBruce]

I do not mean to be a spoil sport, but the tables are not all the same. PADI has its version, NAUI has its version, the Navy has its version. And, as for formulas, every dive computer maker has its own formula or algorithm.

 

[mikemill]

Hi.. I wasn't really sure where to post this topic, but here it goes.

I'm a Computer Science major and for my final project this year I'm making a sort of interactive Dive Log/Dive Planner. Even though the typical computer can do all of these calculations, it's an opportunity to combine programming and scuba. When I took my Nitrox course, I like how the last chapter in the book reviewed equations for calculating Equivalent Air Depth, Contingency Depth, etc. With these equations I can have my program manually determine certain variables without having to refer to Dive Tables.

So my question is: Are there equations for determining Pressure Groups and Surface Intervals for the Recreational Dive Planner? Or am I going to have to enter the entire RDP into a database for my program to refer to? Hopefully this question makes sense... I can clarify if it does not. Thanks!

Regardless of the table and equation the values themselves are gonna be normalized so the equation itself won't be that useful.

What you can do and is quite trivial is to derive a set of equations for a particular table.

 

[rmc77]

For Haldane type models, you will need to solve for each compartment (or tissue) the differential equation: dP/dt = K*(Pa-P), where Pa is the alveolar pressure of the inert gas and P is the inert gas pressure in the compartment on a given time. K is a constant that depends on the specific compartment (related to the half-time - K=ln(2)/half-time). You can either solve this differential equation by numerical or analytical methods.

Once you know the inert gas pressure on each compartment, you will need calculate the minimum depth to which the diver can ascend, using the following formula: dmin = (P-M0)/DM, where M0 and DM are empirical values and are tabled. Bühlmann has 3 sets of values (A,B and C), DCAP has different values, PADI uses DSAT values (tested using Doppler scanners) and are only valid for non-mandatory deco dives.... You will need to calculate for each individual compartment, then use the deepst one as your limit.

There are a lot of good articles you can find in the Internet, even here in the scubaboard. But I would recommend you start checking this site:

Deep Ocean Diving - Science, technology and medicine related to scuba diving

 

[Poggus]

Thanks for all the feedback guys, and thanks for the link rmc.

So basically I could do a couple things. If I wanted to make the planner determine 'pressure groups' and adhere to one specific dive table, then I have to write my code around the table. Like mikemiller said... this is kind of trivial but it would work. Keep in mind I'm not trying to market my project. I just wanted something to program that I'm actually interested in.

Or, like a dive computer I could go off of decompression equations that determine the effects of gas on our tissues while under pressure. I like this idea, but I don't have much knowledge on Dive science and physiology. I guess I'll do some reading and see if this is something I can pursue.

 

[DiveNav]

....Or, like a dive computer I could go off of decompression equations that determine the effects of gas on our tissues while under pressure. I like this idea, but I don't have much knowledge on Dive science and physiology. I guess I'll do some reading and see if this is something I can pursue.

Meanwhile you can play with our free scuba diving simulator ..... bring up the nitrogen loading display tool and see how the various compartments react to your dive profile ... while diving the Spiegel Grove or the Oriskany

BTW, the ZH-L16C source code is on the Internet ..... keep digging

Alberto