Welcome to ScubaBoard, an online scuba diving forum community where you can join over 205,000 divers diving from around the world. If the topic is related to scuba diving, this is the place to find divers talking about it. To gain full access to ScubaBoard (and make this large box go away) you must register for a free account. As a registered member you will be able to:

  • Participate in over 500 dive topic forums and browse from over 5,500,000 posts.
  • Communicate privately with other divers from around the world.
  • Post your own photos or view from well over 100,000 user submitted images.
  • Gain access to our free classifieds marketplace to buy, sell and trade gear, travel and services.
  • Use the calendar to organize your events and enroll in other members' events.
  • Find a dive buddy or communicate directly with scuba equipment manufacturers.

All this and much more is available to you absolutely free when you register for an account, so sign up today!

NEW for 2014 Access SBlogbook for members. It allows you to directly upload data from your dive computer, validate your logs digitally, link your dives to photos, videos, dive centers (9,000 on file), fishes (14,000 on file) and much more.

If you have any problems with the registration process or your account login, please contact the ScubaBoard Support Team.
Results 1 to 10 of 10

Thread: blending calculation tool

 

  1. #1
    Scuba Instructor


    Has not set a "status"
     

    Join Date
    Feb 2004
    Posts
    58

    blending calculation tool

    Hello
    I was fed up of doing some calculations on how much O2 do I have to add on a used tank (with an existing nitrox in it), so I wrote a small java program that runs on my phone.
    It basically prompts for the initial tank pressure, initial FO2, then the desired final tank pressure (usually 3000 psi) and desired final FO2. It then displays how much oxygen needs to be added. It also has a small MOD calculator.

    it runs on any sony ericsson phone, java enabled. I am testing on other phones (motorola, nokia...).

    Anyone that have a sonyEricsson phone and who is interested in testing the software can PM me - you need to have a way to send the program to your phone (bluetooth from your computer, memory stick, IR...). Any feedback welcome.

    eric

  2. #2
    Registered


    Has not set a "status"
     

    darylm74's Avatar
    Join Date
    Feb 2004
    Location
    Pittsburgh PA
    Posts
    716
    Dives
    100 - 199
    Photos
    18

    I have an LG...

    Quote Originally Posted by ericrd
    Hello
    I was fed up of doing some calculations on how much O2 do I have to add on a used tank (with an existing nitrox in it), so I wrote a small java program that runs on my phone.
    It basically prompts for the initial tank pressure, initial FO2, then the desired final tank pressure (usually 3000 psi) and desired final FO2. It then displays how much oxygen needs to be added. It also has a small MOD calculator.

    it runs on any sony ericsson phone, java enabled. I am testing on other phones (motorola, nokia...).

    Anyone that have a sonyEricsson phone and who is interested in testing the software can PM me - you need to have a way to send the program to your phone (bluetooth from your computer, memory stick, IR...). Any feedback welcome.

    eric
    Need to play with it to see if it has java capabilities. If it is Java, it should be portable to any phone running Java since Java is suppose to be platform independent. I would definitely be interested in it.

  3. #3
    Scuba Instructor


    Has not set a "status"
     

    Join Date
    Feb 2004
    Posts
    58
    Hi

    It runs on Java enabled mobile phone - I tested it on Sony Ericsson, Motorola, Panasonic, Nokia. You need to have a way to transfer the app to the handset (via cable, infra red, bluetoooth).

    Instructions are below, program can be downloaded from:
    http://erwanviel.site.voila.fr/blend.zip

    Feedback more than welcome - source available for anyone who wants it (few comments though, but it is really basic stuff).

    eric



    ===============================================
    The version now has 3 functions
    - blending - ie given the current tank content, and the desired mix, computes what quantity of O2 needs to be added.
    - MOD - calculates the MOD for the final mix
    - Top Off

    the main screen contain 4 boxes, that have different use based on the function. Just move the cursor on the text box, hit edit, put the value you want, and hit at the end the more key - three choices should appear - calc, MOD, Top Off.

    Calc.
    This is pretty straightforward, just enter the initial tank pressure and FO2, the final tank pressure and FO2, and hit calc. It is assumed that you take the current tank content, add the O2, and top off with air.
    The result will show how much PSI of O2 you need to add, what will be the tank pressure after you add the O2, the FO2

    after adding the O2, and what happens if your tanks is short filled, by 100,200,300 psi or if you have an extra 100. Apart from the short fill, everything works in PSI or bar, and the unit is not important.

    MOD
    Simply enter on the main screen the final tank FO2 - other paramas are ignored - and hit MOD - you will see the MOD at 1.4 and 1.6, in feet and meters.

    Top-off
    You currently have a tank with initial Tank Pressure and FO2. YOu are topping off with a gas with 'Final FO2' of oxygen, and up to Final tank pressure - you get to see the final FO2 in the mix.

    Calcualtion details
    Java CLDC1.0 does not support floats, so to do these calculations, one has to multiply all figures by a 100, and divide at the very last moment - therefore, the precision is not as good as you would get with float calcs, but are still fairly accurate, at least in PSI - no more than 1-2 psi of max difference.

  4. #4
    Registered


    Has not set a "status"
     

    darylm74's Avatar
    Join Date
    Feb 2004
    Location
    Pittsburgh PA
    Posts
    716
    Dives
    100 - 199
    Photos
    18
    Thanks. I am going to play with it tomorrow and see if I can get it on the phone, if not I work for a wireless infrastructure (we own a lot of cellphone towers) company and I'm sure the engineers there will have some ingenious way to do it. If they can't do anything, this would still be valuable on a PDA.

    Thanks again

    Daryl

  5. #5
    Registered


    Is it dive o'clock yet?
     

    Tamas's Avatar
    Join Date
    Mar 2004
    Location
    Toronto Ontario Canada -eh?
    Posts
    2,190
    Photos
    47
    Quote Originally Posted by ericrd
    Hello
    I was fed up of doing some calculations on how much O2 do I have to add on a used tank (with an existing nitrox in it), so I wrote a small java program that runs on my phone.
    It basically prompts for the initial tank pressure, initial FO2, then the desired final tank pressure (usually 3000 psi) and desired final FO2. It then displays how much oxygen needs to be added. It also has a small MOD calculator.

    it runs on any sony ericsson phone, java enabled. I am testing on other phones (motorola, nokia...).

    Anyone that have a sonyEricsson phone and who is interested in testing the software can PM me - you need to have a way to send the program to your phone (bluetooth from your computer, memory stick, IR...). Any feedback welcome.

    eric
    OH-OH ME-me.....I have been bugging one of my coders to write one for the longest time....but this way I won't have to

    I like.....very simple yet to the point. Can you add a calc for 1.5?

    I also noticed it's off a few PSI in the O2 calc, +4-5%
    Tamas

  6. #6
    Scuba Instructor


    Has not set a "status"
     

    Join Date
    Feb 2004
    Posts
    58
    Quote Originally Posted by Tamas
    OH-OH ME-me.....I have been bugging one of my coders to write one for the longest time....but this way I won't have to

    I like.....very simple yet to the point. Can you add a calc for 1.5?

    I also noticed it's off a few PSI in the O2 calc, +4-5%
    . calc for 1.5 - I guess you mean MOD ? sure
    . off for o2 calc, +4-5% - can you give an example, so I look at what is happening

    tks for the feedback

    eric

  7. #7
    Registered


    Is it dive o'clock yet?
     

    Tamas's Avatar
    Join Date
    Mar 2004
    Location
    Toronto Ontario Canada -eh?
    Posts
    2,190
    Photos
    47
    Quote Originally Posted by ericrd
    . calc for 1.5 - I guess you mean MOD ? sure
    . off for o2 calc, +4-5% - can you give an example, so I look at what is happening

    tks for the feedback

    eric
    Yes 1.5ATA for MOD, you have 1.3 and 1.6, would be nice (if possible) to have a 1.4 and a 1.5 calc to cover all the bases

    The diff, sure when I use the standard 500psi @ 21% --> 3000psi @ 32% your blender gives me 420 psi to fill then top off with air while the other blender(s) I use say to use 417.7 psi....the higher the O2 % the more the variance.....usually off by +2-3psi.....nothing really major but could be

    other than that, it's cool!
    Tamas

  8. #8
    Scuba Instructor


    Has not set a "status"
     

    Join Date
    Feb 2004
    Posts
    58
    Hi
    MOD is currently working for 1.4 and 1.6 - I'll add 1.5 and 1.3

    Calculations - I took 20.9 and 79.1 as top-up gas.
    The formula is:
    (((Final_Tank_Pressure*Final_FO2-Initial_Tank_Pressure*Initial_FO2)/Delta - TopUp_o2)/TopUp_N2)*Delta

    and it gives 420.354 - when using 21/79, you get to 417.7

    I found the following web site:
    http://www.atomox.com/mix_calc.html

    which shows real gas vs ideal ga. I may implement the calculation.

    Let me know if you think something is wrong here,

    Eric

  9. #9
    Registered


    Is it dive o'clock yet?
     

    Tamas's Avatar
    Join Date
    Mar 2004
    Location
    Toronto Ontario Canada -eh?
    Posts
    2,190
    Photos
    47
    Quote Originally Posted by ericrd
    Hi
    MOD is currently working for 1.4 and 1.6 - I'll add 1.5 and 1.3

    Calculations - I took 20.9 and 79.1 as top-up gas.
    The formula is:
    (((Final_Tank_Pressure*Final_FO2-Initial_Tank_Pressure*Initial_FO2)/Delta - TopUp_o2)/TopUp_N2)*Delta

    and it gives 420.354 - when using 21/79, you get to 417.7

    I found the following web site:
    http://www.atomox.com/mix_calc.html

    which shows real gas vs ideal ga. I may implement the calculation.

    Let me know if you think something is wrong here,

    Eric
    AHA! That would make sense then on the final numbers.

    You mentioned you would share the code? Is that still so?
    Tamas

  10. #10
    Scuba Instructor


    Has not set a "status"
     

    Join Date
    Feb 2004
    Posts
    58
    code: absolutely ! pm your email @ and I'll also send how to set up the dev environment.

    eric

Similar Threads

  1. SAC rate calculation...
    By scottfiji in forum Basic Scuba Discussions
    Replies: 15
    Last Post: February 13th, 2005, 08:23 PM
  2. Air and Time Calculation
    By Guillotine in forum New Divers and Those Considering Diving
    Replies: 7
    Last Post: October 3rd, 2004, 07:03 AM
  3. Smart-Com RBT Calculation
    By Web Monkey in forum Computers, Gauges, Watches and Analyzers
    Replies: 1
    Last Post: April 17th, 2004, 11:30 PM
  4. Buhlmann Calculation Help
    By lamont in forum Ask Dr. Decompression
    Replies: 2
    Last Post: December 1st, 2003, 01:23 PM
  5. SAC calculation
    By thethumper in forum General Scuba Equipment Discussions
    Replies: 28
    Last Post: October 23rd, 2002, 02:41 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •