ScubaCapsule : New 'It's Got EVERYTHING' Computer

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There is another thread on this.
 
That looks awesome... I am quite interested as to how well it works and how reliable it would be... funny thing is.. first thought that comes to mind is "dang an iphone is expensive.. would hate to ruin it!" but then I realize most decent dive computers are as expensive if not more so already lol
 
I posted on this back last October, in this thread, #682-684 http://www.scubaboard.com/forums/co...tics-cobalt-dive-computer-28.html#post6096335

From those posts:
... the iPod/ iPhone doesn't have any pressure sensors, so you would need a sensor for depth (and tank pressure, if it was AI) and a processor and circuitry to convert the signal into something that could be transmitted to the iPod. We considered doing something like this years ago with the Palm, but rejected the idea after looking at the tradeoffs vs. a dedicated unit. One concern would be battery life- I use my iPhone as a timer/ GPS for rowing, and after running the display for an hour it is at least 40% depleted.

Some of the algorithm comments (on another site related to this same product, where they indicate that the accuracy of an algorithm is related to the number of tissue groups, and suggest they could use up to 256) leave me doing a bit of head scratching.

There are a number of issues in using something like the iPhone for a processor/ display unit. They are all solvable at some level, but there is a point of diminishing returns, where a dedicated device starts looking like a better answer- particularly in a difficult environment like underwater. And there is a lot more to a functional dive computer than the obvious basics- a big part of the interface is working out how you handle unexpected events, when the diver does the "wrong" thing.
Just off the top of my head:
  • Battery life and/ or charging in the case would need to be resolved to a satisfactory level.
  • Interacting with the computer when it is in the case (no touchscreen function, and accelerometer sensing has some quirks, though it can be done) would need to be really well thought out.
  • You still need a microprocessor, software and circuitry (essentially a small dive computer with no display) to get the sensor signals converted to something the iPhone can handle.
  • You're hoping that the form factor doesn't change too rapidly, as you are hitching yourself to a big company's plans (probably not a huge concern with the iPod/ iPhone, since there are already so many).
On the plus side:
  • iPhone has plenty of processing horsepower and a nice, big screen
  • The iOS development tools make creating a user interface (or a snazzy looking demo) a very easy task, compared to developing a dedicated unit.
  • There are a lot of iPhone/ iPods out in the world. Done right, and not over hyped, it might be a path to a relatively low cost color computer. You would have to make all the parts really inexpensive for it to work out, though.
For each of the last couple of years there has been some sort of iPhone in a box solution shown as a dive computer. So far as I know none of them have yet become shipping products. There is no reason it couldn't be done, but it may be less ideal than it seems at first glance. Done right, though, it could have potential.

To explain the 1st comment, tissue groups in deco theory are mathematical abstractions. If the underlying theory doesn't account for them, more is not better. It's like taking a digital image and subdividing it into more pixels- it doesn't improve accuracy, just slows processing. Decompression computations are broad brush guidelines, not precision calculations.

The real-time aspect of decompression algorithm implementation is a lot more challenging than it seems superficially, and takes a lot of testing. The hardware is the easy part. There were prototypes of this product at DEMA. It will be interesting to see if it turns into a selling product.

Ron
 
The battery issue life really isn't an issue. What sucks down battery life is transmision. Put your iPhone in airplane mode (none of the phone functions are going to work underwater anyway) and see how long the battery lasts.
I don't know if this product will make it, especially from a startup (which lacks the financial resources of a bigger company), but it's a very interesting product, and if it does make it, I'd like one.
 
The battery issue life really isn't an issue. What sucks down battery life is transmision. Put your iPhone in airplane mode (none of the phone functions are going to work underwater anyway) and see how long the battery lasts.
I don't know if this product will make it, especially from a startup (which lacks the financial resources of a bigger company), but it's a very interesting product, and if it does make it, I'd like one.
Transmission is a part, as is the GPS (what I'm using on my iPhone when rowing), and neither will work underwater so it makes sense to turn them off. But if you have the display always on, as opposed to going dark, it is going to draw quite a bit of power. Backlighting needed for a TFT displays is a big drain. My phone charge holds up for a few days passively sitting without turning off phone or wi fi functions, but if I use an app that runs the display constantly it's depleted very quickly- as in a few hours. What I recall they said at DEMA is that they got something like eight hours- I could be remembering incorrectly. If so, they have done some things to lessen the draw from the display- perhaps dimming the backlighting or turning it off until shaken?

Ron
 
Transmission is a part, as is the GPS (what I'm using on my iPhone when rowing), and neither will work underwater so it makes sense to turn them off. But if you have the display always on, as opposed to going dark, it is going to draw quite a bit of power. Backlighting needed for a TFT displays is a big drain. My phone charge holds up for a few days passively sitting without turning off phone or wi fi functions, but if I use an app that runs the display constantly it's depleted very quickly- as in a few hours. What I recall they said at DEMA is that they got something like eight hours- I could be remembering incorrectly. If so, they have done some things to lessen the draw from the display- perhaps dimming the backlighting or turning it off until shaken?

Ron

The GPS in the iPhone uses WiFi hotspots and cell towers. Exactly the same as talking on your phone. :)

I don't have the ScubaCapsule software, obviously, but as soon as I posted that prior message, I took my iPhone 4 off the charger, put in airplane mode, and turned on Angry Birds. That runs the display (actively, not just a passive image) and the audio. I even turned up the volume all the way to maximise the power usage. Just as an aside, I'm really sick of the Angry Birds song now.

After an hour, I'm at 88%. That means I've got a good 8.5 hours of usage, non-stop, screen lit. Tha seems plenty to me. And if not, I know they offer a combination drybag/solar powered rapid charger on their website.
 
https://www.shearwater.com/products/perdix-ai/

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