Garmin entering the dive industry?

[Lorenzoid]

Totally up my old alley--the kind of thing I would have been into in my youth--but these days I spend all my money and spare time on diving and travel.

Back to Garmin.

 

[victorzamora]

I believe they're called Ratio and can be bought wherever dive computers are sold. Dunno how much course plotting they actually do/log.

Oh, and these huge classified mega-expensive things are actually the size of a US quarter and cost ten bucks: Pololu - MinIMU-9 v3 Gyro, Accelerometer, and Compass (L3GD20H and LSM303D Carrier)

One quick note before this sidetrack gets corrected: IMUs are PART of most INS systems, but are simply the inputs that then need to be calibrated, ingested, mucked about with, tuned, and then tracked/logged. You can certainly get it smaller than a Petrel, but there's a lot more to it all than simply strapping an IMU on the side of something.

 

[dmaziuk]

Although etching a nice board is far easier these days as you can use a laser cutter instead of a pen and a bunch of nasty chemicals that dissolve copper plating.

The other stuff that happens nowadays is if you can implement your program at TTL level you can solder it into an FPGA chip. Once there, and if you really want to: shrink that into an "Application-Specific IC". The only problem is Chinese IC bakers won't run a batch smaller than several thousands for you.

 

[T.C.]

In college I worked with a team developing an IMU-based INS, but the goal was to cross-reference INS outputs with the navigation information gleaned from other (more sensitive) navigation methods. They used the IMUs partially in conjunction with the "other" system, but also used them for more "normal" INS. The biggest issue with INS is that it's really, really tough to compensate for drift due to things like current.


Ours was this size (maybe a touch bigger) including battery, but could've been done smaller on fully custom hardware instead of the off-the-shelf stuff we were using for prototyping.

I don't know if it compensates for drift, It never came up. What's an IMU?

I'm sure it can be made smaller if you have an unlimited research budget, too.

 

[victorzamora]

I don't know if it compensates for drift, It never came up. What's an IMU?

I'm sure it can be made smaller if you have an unlimited research budget, too.

IMU is an "Inertial Measurement Unit" and measures rotational and linear accelerations about and in all three axes.

As for the size: we could've gotten much smaller with a fairly reasonable budget. We were in the prototyping and generic stage so our compute unit was mostly what we knew well and trusted.

 

[T.C.]

IMU is an "Inertial Measurement Unit" and measures rotational and linear accelerations about and in all three axes.

As for the size: we could've gotten much smaller with a fairly reasonable budget. We were in the prototyping and generic stage so our compute unit was mostly what we knew well and trusted.

Thanks!

I know you could do smaller, it was just a joke about how the military has the resources to pay for what they want.

 

[victorzamora]

Thanks!

I know you could do smaller, it was just a joke about how the military has the resources to pay for what they want.

I think in Cave Diving, the vast majority of us would be totally cool with a Petrel-sized INS unit for mapping/tracking. I know it'd be great to have one for OW dives in lower visibility or in high-current conditions. A buddy does a lot of California shore-based diving and would absolutely love to be able to scooter back from his distant destinations without the fear of getting lost (he's currently got two compasses and an underwater topological map).

The implementation of an INS is mostly limited by man-hours. If divers wanted one, we could build one....it's just a lot of time or money, and few have seen true value in it. Drift compensation is still a huge issue , especially since we're dealing with such hilariously strong currents (often more impactful than we could swim against) with no good way of compensating for it (drift compensation and recalibration were areas of focus in my research).

 

[Alastor]

I think it could be very useful in cave exploration - where drift should be not an issue.
An IMU can log the path in 3D and then, after the dive, the log can be downloaded on a PC allowing to check the exploration progress and help to find connections.
This other than visualize the path back to the exit, even in very bad visibility.
just my 2c

 

[stuartv]

I think it could be very useful in cave exploration - where drift should be not an issue.

Drift comes from current, right? Lots of caves have current, right?

 

[Alastor]

I have no direct experience, i just thought the water is mostly not moving there. My mistake..