Shearwater NERD 2 "for OC Divers"

[stuartv]

It looks cool to me. I'm on a path towards CCR and I already have a Perdix AI and 2 transmitters, so I could definitely see getting a NERD2 for CCR use. But, even as much of an AI fan as I am, I'm having a hard time seeing how this really fits into a plan for even recreational OC diving, much less tech. If they had a clamp that would mount it on a normal mask, then yes. But, mounted on the 2nd stage hose? That is not great for tech divers, doing gas switches. But, it also doesn't even really "work" for recreational sidemount divers. Or anybody that uses the primary donate protocol.

The web page talks about the 2-hole mount, which will allow custom mounts to be made and they even call out a mask mount as an example. But, I sure would have thought they would have designed something for that already. Maybe even instead of the LP hose mount. The LP hose mount is SO limited in terms of usefulness.

 

[doctormike]

@doctormike think smccr's. No t-pieces, no place to put it so it ends up a bit of a mess. I personally don't see the rechargeable battery as an issue and I think it's getting a bit overblown. Lots of bad history from nicad and early nimh days that are unfortunately carrying over into lipo
With daily use and charging, cell phone batteries last 2-3 years. They also have quite accurate battery gauges in them and allow a much smaller form factor than using alkalines. Sure the user replaceable is really nice in the petrel, but to get it smaller, it has to get integrated with a cellphone style battery, no real way around it.

Oh, yeah... clearly a small rechargeable has advantages over a bulky AA box for some things. I just don't see this as being one of them.

It's not like the tradeoff is between the standalone with no cable and the NERD 1 with a cable - you still need a cable if you are using this on a CCR. And while I don't know what all the various CCR designs look like, at some point it has to plug into the head, so it seems that there would be some place to stow the box out of the way (clipped to the loop itself, zip tied to something, clipped to the harness, etc..). But I'll take your word for it if you have tried it.

 

[tbone1004]

@doctormike so I'm obviously not the Partridges so I can't put words in their mouth, but I am a design engineer.
Here's how this probably went down

"NERD needs a refresh, what can we do?"
"Let's make it WAI because that would save some hoses on the CCR's and divers like Becky Schott are using a Perdix with transmitters now, and the X-ccr has wired stuff, so wouldn't it be cool if we could just shove it in the NERD?"
"yeah, that sounds like a good idea, what else can we do to make that design effort worth the cost?"
"well we can remove the entire box without greatly increasing the form factor if we put a small rechargeable battery in it"
"cool, let's do that"

Basically, there really is probably no good reason for the box other than it made the development cheaper/easier by using a lot of similar machining as the Petrel and allowed the battery compartment and PCB to remain the same which saved cost in engineering and parts.
Form factor actually looks about the same as the original NERD so I don't really see a downside to it. They increased functionality and decreased overall size. That's a pro.
Battery is rated at 500 charge cycles or 5 years. Assume you probably get 10 hours per charge cycle on it, that's 5k hours and in 5 years the battery replacement is probably going to be pretty reasonable cost wise

 

[stuartv]

Oh, yeah... clearly a small rechargeable has advantages over a bulky AA box for some things. I just don't see this as being one of them.

It's not like the tradeoff is between the standalone with no cable and the NERD 1 with a cable - you still need a cable if you are using this on a CCR. And while I don't know what all the various CCR designs look like, at some point it has to plug into the head, so it seems that there would be some place to stow the box out of the way (clipped to the loop itself, zip tied to something, clipped to the harness, etc..). But I'll take your word for it if you have tried it.

It has AI (meaning, it already has an RF receiver). Why not use wireless for O2 monitoring also? I mean, a cable from the head to a small box that is mounted near the head. And then wireless from the box to the NERD. Or, maybe Shearwater will come up with a wireless DiveCan spec and sell a small box that plugs into the DiveCan and then sends any/all data to the NERD via wireless.

 

[doctormike]

Basically, there really is probably no good reason for the box other than it made the development cheaper/easier by using a lot of similar machining as the Petrel and allowed the battery compartment and PCB to remain the same which saved cost in engineering and parts.
Form factor actually looks about the same as the original NERD so I don't really see a downside to it. They increased functionality and decreased overall size. That's a pro.
Battery is rated at 500 charge cycles or 5 years. Assume you probably get 10 hours per charge cycle on it, that's 5k hours and in 5 years the battery replacement is probably going to be pretty reasonable cost wise

Yeah, you may be right. I'm just really happy with the current AA battery system so I might not see the advantages of the alternative. I change batteries once a season or so, but there have been times when I have started with a "full" AA on the controller and had it drop quicker than expected during the dive. Maybe the new tech is better. It just looked much bulkier on the web page, and it is twice the weight on the spec sheet, but as I said, I haven't seen one in the flesh.

 

[CuzzA]

It looks cool to me. I'm on a path towards CCR and I already have a Perdix AI and 2 transmitters, so I could definitely see getting a NERD2 for CCR use. But, even as much of an AI fan as I am, I'm having a hard time seeing how this really fits into a plan for even recreational OC diving, much less tech. If they had a clamp that would mount it on a normal mask, then yes. But, mounted on the 2nd stage hose? That is not great for tech divers, doing gas switches. But, it also doesn't even really "work" for recreational sidemount divers. Or anybody that uses the primary donate protocol.

The web page talks about the 2-hole mount, which will allow custom mounts to be made and they even call out a mask mount as an example. But, I sure would have thought they would have designed something for that already. Maybe even instead of the LP hose mount. The LP hose mount is SO limited in terms of usefulness.

It does look like it has a GoPro-esque mount to it. If anything they should just use the same mount as a GoPro. Then I could see this being a little more practical for someone who really wants it. Mount it on any mask, a helmet, a selfie stick .

 

[doctormike]

It has AI (meaning, it already has an RF receiver). Why not use wireless for O2 monitoring also? I mean, a cable from the head to a small box that is mounted near the head. And then wireless from the box to the NERD. Or, maybe Shearwater will come up with a wireless DiveCan spec and sell a small box that plugs into the DiveCan and then sends any/all data to the NERD via wireless.

SPGs and AI are more of an OC thing.

The JJ has the SPGs tucked way in the back, out of the way. The only time that I look at them during a dive is for a boom drill (gas leak). Other than that, you don't really spend a lot of time monitoring O2 pressure. O2 goes faster than dil, so if you know how long you are diving and how much you started with, you have a pretty good idea of how much you have left (consumption is independent of depth). With a good fill, I would probably run out of scrubber before O2, even with a fairly heavy workload. I have seen some divers actually replace the SPGs with button gauges since they never look at them during a dive.

And if you had some sort of catastrophic O2 loss, you would know it without looking at the SPG (solenoid and MAV not working), so you would bail out (or plug in offboard O2 or a rich mix if you had that).

 

[stuartv]

My point was not to say that they should do AI in the NERD. It already does that anyway. My point was that they could use the basic hardware that is already there to send ppO2 data (and CO2 data, on units with the right sensor, and tank pressure data, too, if they want) using a box that connects to the DiveCan and then sends the data wirelessly to the NERD.

I.e. a NERD2 that clips to your mask, has no wires at all, and can display your O2 sensor data, your CO2 sensor data, your tank pressure sensor data (without having to buy AI transmitters, if the CCR has built-in tank pressure sensors), and any other data (sorb temp?) that currently only gets sent to the controller that is hardwired to the head. Maybe even let you control your setpoint from the NERD (at least, as a redundant controller in case the primary controller croaks)?

 

[doctormike]

My point was not to say that they should do AI in the NERD. It already does that anyway. My point was that they could use the basic hardware that is already there to send ppO2 data (and CO2 data, on units with the right sensor, and tank pressure data, too, if they want) using a box that connects to the DiveCan and then sends the data wirelessly to the NERD.

I.e. a NERD2 that clips to your mask, has no wires at all, and can display your O2 sensor data, your CO2 sensor data, your tank pressure sensor data (without having to buy AI transmitters, if the CCR has built-in tank pressure sensors), and any other data (sorb temp?) that currently only gets sent to the controller that is hardwired to the head. Maybe even let you control your setpoint from the NERD (at least, as a redundant controller in case the primary controller croaks)?

Oh, I see. Yeah, I guess that would be OK as long as there was a wired controller. Not to open up the eternal ScubaBoard WAI debates again in this thread, but I didn't find WAI reliable enough to use on OC, where a link failure was just an annoyance. On CCR, I definitely wouldn't want my primary controller to be dependent on a wireless signal.

 

[Scared Silly]

The mount is right side only. So great for right eyed dominate people. Not sure how well it will work for left eyed dominate people. Fortunately on 10% of the people are lefties. Of course then there who are cross dominant.