Alexa, what's the MOD?

[Sean Walberg]

A bigger issue for me would be no access to Alexa when I'm on a dive boat with no wi-fi.

A standalone app might be of more use.

Yea, I'm under no illusions that this would be helpful on a boat, or even at all, except for maybe at home planning or when picking up tanks at a dive shop. Honestly the goal here was to write an Alexa skill of any description, and the most realistic thing that came to mind was Nitrox. My first scuba related idea was to make a voice interface to divebuddy.com but the scope started getting out of hand.

Maybe to rephrase my question -- is there any scuba related thing that one could use voice first approach for? Preferably where the voice interface can make it better.

 

[The Chairman]

I was trying to learn more about Alexa skills and I happen to just have completed my Nitrox class, so I made a skill to calculate best mix and MOD. Ask Alexa for the "nitrox calculator" skill. Would love to hear any thoughts!

I absolutely love this. Thanks. I don't need it, but it is kinda fun. Can't wait to show it off to dive buddies.

 

[boulderjohn]

If you wanted to mess with something like that, make a more sophisticated MOD product. I would bet that 99% of the decisions for MOD around the world come from people either looking at a standard chart or people remembering that standard chart. I doubt if more than a relative handful of people know the math for it, and that is about the number that care about it. What most of them do not realize is that the chart is only accurate for salt water diving at sea level. It is not accurate for other diving.

It really doesn't matter for most diving, though, because using the salt water/sea level MOD chart for fresh water/altitude diving is actually safer. It does matter in some cases in which people are trying to use the best possible mix for extended diving times, and it also matters for people planning decompression dives and are mixing gases both for the bottom gas and for the decompression gases. I do most of my diving at about 4.600 feet, and my teammates, students, and I know that the sea level/salt chart is not accurate. The dive computer I use (Shearwater) knows this, of course, but that only helps me after I am in the water. For dive planning ahead of time, I use a MOD chart that I created for that altitude.

 

[Sean Walberg]

I do most of my diving at about 4.600 feet, and my teammates, students, and I know that the sea level/salt chart is not accurate.

How does that change the calculations? Is it just in that extra atmosphere we calculate on top e.g. at 33' you'd be at around 1.84ATM and not 2?

 

[Damselfish]

A standalone app might be of more use.

But not nearly as amusing.

 

[boulderjohn]

How does that change the calculations? Is it just in that extra atmosphere we calculate on top e.g. at 33' you'd be at around 1.84ATM and not 2?

You would use 34 feet for the water ATAs.

Sea Level MOD for EAN 32: using the 1.4 standard:

1.4/.32 = 4.375 ATA [find the pressure to achieve that PPO2]
4.375 - 1.0 = 3.375 [Subtract the weight of the atmosphere to find water pressure]
3.375 X 33 = 111.375 feet [Multiply by weight of water needed to equal one ATA.]
​

6,000 feet altitude (0.8 ATA) MOD for EAN 32: using the 1.4 standard:

1.4/.32 = 4.375 ATA
4.375 - 0.8 = 3.575
3.575 X 34 = 121.55 feet​

 

[Parklander]

Good work! I praise anyone that dives into appdev for our sport. Oh, and yeah. Those devices are even more risky than social media.

 

[Saniflush]

I wrote off asking for voice online help when Siri first came out and I froze up a buddies phone when I asked it "what the air speed velocity of a coconut laden swallow" was? If it can't answer that, then I don't need it.

 

[Parklander]

What do you mean? An African or European swallow?

 

[MaxE]

I also think having an internet connected microphone in your house is a bad idea.

Like the phone you have in your hand? Let’s be real, we all carry around a microphone and camera (front and rear facing) 24hrs a day that is connected to the internet and giving you location on the earth within a few feet.