PERDIX or PERDIX AI?

[doctormike]

I'd say it's a misconception is that if the computer loses the transmitter's signal you need to call the dive immediately. I've had my dc lose contact with my transmitter many times. It always reconnects a couple seconds later. It's innocuous enough that I disabled the associated alarm. I'm using a scuapro Galileo, but I ass-u-me there are no features (like the reconnect) which scubapro has but shearwater lacks.

I later changed to a higher voltage battery which has resolved that intermittent disconnect problem.

Yeah, I assume that he meant an unrecoverable failure.

And look, yet another report of a failed WAI link!

As far as I'm concerned, the main advantage of WAI is data logging, for people who like to upload their gas consumption to their logs.

 

[kelemvor]

Only if you're including automatically recovered failures. I don't believe I've ever had mine disconnect for more than a couple seconds when underwater. Like I said, when the battery was replaced with a model rated for 0.6v higher voltage it resolved all those issues for me permanently.

 

[doctormike]

Only if you're including automatically recovered failures. I don't believe I've ever had mine disconnect for more than a couple seconds when underwater. Like I said, when the battery was replaced with a model rated for 0.6v higher voltage it resolved all those issues for me permanently.

Yeah, I'm kidding. It may well be that in 2019, WAI failures are down to the rate of SPG failures (I have had one), so who knows. Maybe some industry numbers are out there. But I still like SPGs.

 

[kelemvor]

Yeah, I'm kidding. It may well be that in 2019, WAI failures are down to the rate of SPG failures (I have had one), so who knows. Maybe some industry numbers are out there. But I still like SPGs.

I'd like to see transmitters with metal housings. That would make it a more robust solution for overheads, although a slight form factor change would be needed to eliminate entanglement risks. I'm thinking like a wider but shorter unit. Transmitters are so rediculously simple from an electronics perspective I might be inclined to try building my own at the Tampa Hackerspace this year. If only I had my own lathe

 

[doctormike]

I'd like to see transmitters with metal housings. That would make it a more robust solution for overheads, although a slight form factor change would be needed to eliminate entanglement risks. I'm thinking like a wider but shorter unit. Transmitters are so rediculously simple from an electronics perspective I might be inclined to try building my own at the Tampa Hackerspace this year. If only I had my own lathe

The next step will be integrating the transmitter into the first stage. That way, an electronics problem can also cause a gas flow problem!

I'm amazed that people put these on CCR bottles. That seems like a step in the wrong direction, you really don't need that sort of gas monitoring on a rebreather. I don't even like having my SPGs in the front of the rig, it's cluttered, I have them stowed away behind me. And some people just put button gauges on the tanks so that they can check them at the beginning of the dive. That seems a bit much, you occasionally do need an SPG (i.e. managing a boom).

 

[stuartv]

I really should know but where do you get that info?

As has been noted, the Perdix does not have a positive check.

I check mine using my Oceanic Atom 3.0 computer. On it, it will display battery status for the computer battery and for the battery of each transmitter it is connected to. It says "Good".

 

[stuartv]

The next step will be integrating the transmitter into the first stage. That way, an electronics problem can also cause a gas flow problem!

I'm amazed that people put these on CCR bottles. That seems like a step in the wrong direction, you really don't need that sort of gas monitoring on a rebreather. I don't even like having my SPGs in the front of the rig, it's cluttered, I have them stowed away behind me. And some people just put button gauges on the tanks so that they can check them at the beginning of the dive. That seems a bit much, you occasionally do need an SPG (i.e. managing a boom).

I am planning to put AI transmitters on my rEvo. I have never had an issue with a WAI transmitter. I have had a spool blowout on an SPG on my twinset regs and I have had 2 times already, in my very short time with my rEvo, where one of the SPGs on it was leaking.

I don't really see a downside to replacing the SPGs on my rEvo with AI transmitters. Less clutter. Less opportunity for a gas leak. Not a big deal at all if one were to totally die (but also very unlikely, in my experience and opinion). Should be well-protected from hitting or snagging on anything (but that remains to be seen, depending on if they actually fit where I want to put them).

 

[kelemvor]

I bet the transmitter doesn't send any more than that. Actually it probably ONLY sends battery data when the battery is low. Sending battery data all the time would consume battery power. My scubapro computers with wireless ai also only indicate battery level if it is low. You get a message "T1 Battery Low" or whatever number corresponds to the transmitter in question. I think it supports 6 or 8 at a time.

 

[kelemvor]

The next step will be integrating the transmitter into the first stage. That way, an electronics problem can also cause a gas flow problem!

I'm amazed that people put these on CCR bottles. That seems like a step in the wrong direction, you really don't need that sort of gas monitoring on a rebreather. I don't even like having my SPGs in the front of the rig, it's cluttered, I have them stowed away behind me. And some people just put button gauges on the tanks so that they can check them at the beginning of the dive. That seems a bit much, you occasionally do need an SPG (i.e. managing a boom).

That clutter problem is probably exactly why they do it. You could eliminate both spgs entirely and see the pressure data on your computer along with everything else.

Maybe it's a terrible idea for reasons I don't understand given that I know precious little about rebreathers.

 

[stuartv]

I bet the transmitter doesn't send any more than that. Actually it probably ONLY sends battery data when the battery is low. Sending battery data all the time would consume battery power. My scubapro computers with wireless ai also only indicate battery level if it is low. You get a message "T1 Battery Low" or whatever number corresponds to the transmitter in question. I think it supports 6 or 8 at a time.

If it sends a battery voltage level reading as part of every data packet (which is what, every 5 seconds?), I don't think that would really make a big difference on battery life. But, I could be TOTALLY wrong. However, my suspicion is that the simplest solution for implementing that transmitter was one simple protocol with one data packet format. TX ID, current pressure reading, and current battery voltage. And maybe a protocol version specifier, to allow for future compatibility. The battery voltage would only require, at most, 4 or 5 or maybe 6 bits. Seemingly being the simplest, I bet that's what they did. A solution that had it transmitting one type of data packet for pressure data and then, occasionally, a different kind of data packet for battery status seems less likely, to me.

But, that really is pure speculation.