Hammerhead Electronics

[padiscubapro]

After a few draft revisions, I have released the first official hammerhead owners manual. It is now available for download from the manufacturers web site.

Anyone contemplating the purchase of rebreather electronics should take a look at this free download.

http://www.electricfilm.com/HH_manual_30.PDF

[caveseeker7]

After Kevin ran me through it in Miami BEach I was hoping for that.
Oughta make an intresting read. Thanks for the link, and have a good weekend.
Stefan

[padiscubapro]

caveseeker7 once bubbled...
After Kevin ran me through it in Miami BEach I was hoping for that.
Oughta make an intresting read. Thanks for the link, and have a good weekend.
Stefan

Actually stephan,
I wrote virtually the entire manual, did all the charts and document formatting..
while Kevin did all the photos, His "threat matrix" + flippant Oxygen cell remarks(both of which I reworded), lots of hints on what he though was necessary in the manual, what he wanted specific things called and of course clarifying specific points that only the programmers + Kevin Knew.
A project like this works best when one person "speaking" so multiple conflicting voices are avoided..
Kevin's writing style is passionate more of a novelist approach, while my writing is concise, clear and "tutorial".

If you read though the various pages on his website you'll see what I mean...

[madmole]

Well done Joe

Nice bit of work

[caveseeker7]

padiscubapro once bubbled...
... while Kevin did all the photos, His "threat matrix" + flippant Oxygen cell remarks...If you read though the various pages on his website you'll see what I mean...
Yeah, I know. :D Is there a copy of those cell remarks?

You did a great job writing the manual. Congratulations.
So it's official now, the HH will be a Meg factory option. :)

[padiscubapro]

caveseeker7 once bubbled...

Yeah, I know. :D Is there a copy of those cell remarks?

You did a great job writing the manual. Congratulations.
So it's official now, the HH will be a Meg factory option. :)

There are still issues that have to be worked out, but by the time anyone who puts in an order configured that way, things should be resolved.

In the section entiled oxygen cells (in italics) right before the maintenance section), you should get the general idea..

It just reads a bit better now...

[VoodooGas]

Dude....I gotta tell ya I am not really impressed with the Hammerhead. Why wouldn't Kevin include NDL on the units....kinda lame if you ask me.

[padiscubapro]

Dude....I gotta tell ya I am not really impressed with the Hammerhead. Why wouldn't Kevin include NDL on the units....kinda lame if you ask me.
I agree with kevin on this one (with one exception)...

The HH was designed as a full trimix decompression computer and a majority of the owners are using it as such.. In these conditions guessing the NDLs are just shot in the dark(some computers do a better job than others).. No computer gets it right so why put such useless information.. Its not uncommon to just exceed a NDL and immediately have 10 minutes of deco.. obviously the guess isn't that good..

If you are using straight air or heliox the NDLs can be readily predicted, adding it would probably make a few people happy, but most of us don't care since our dives are planned out ahead of time, are decompression dives, are trimix dives or also have another computer like the explorer added to the loop..

The Key things with the HH is the Trimix integration, dead on PO2 control, and reliability. kevin always looks for suggestions on improving the unit, and listens to what people want.. Join the Yahoo group and see what people request.. There have only been a few who have asked about the NDLs and those really aren't doing the dives that make the unit shine..
Even without a NDL display it still is considerably more functional than the standard controller.

The deco alg in the HH is superior to the VR3, is truely customizable.. I can ajdust the gradients to give me a curve similiar to a bubble model like RGBM in the Explorer and then change the GF mid dive to get a little more agressive on the shallow stops to give ending run times closer to RGBM.

[madmole]

I actually disagree and think the missing NST's are a bad point. I'm often diving with Sports divers who do not want to do deco and I want to know how much time I have left

Also as a programmer who has written his own deco software and hacked a few other dive computers over the years. Its actually a trivial itteration to work out when your going into deco if you stay at the current depth and on the current PO2 and mix. Heaven forbid even Alladin can manage it!!!

As long as the diver understands the way the model works and that going deeper or swapping to a lower PO2 or higher PHe will lower the NST then its a valid thing to display. For example its very useful for getting a feel for when to head for the Shot to ascend with trainee's

Granted on a deep mix dive you are going into deco and you plan in advance, but not all of us use our HH's for just mega dives

But it still is a great tool and is getting better

[padiscubapro]

Also as a programmer who has written his own deco software and hacked a few other dive computers over the years. Its actually a trivial itteration to work out when your going into deco if you stay at the current depth and on the current PO2 and mix. Heaven forbid even Alladin can manage it!!!


only as long as a single inert gas is present (helium or nitrogen).. All the differential eq solutions are for single gas. The NDL is a simple equation for this solution. None of the other three trimix capable computers ( VR3, Nitek He or Explorer) accurately estimate NDLs for trimix dives.. They all take guesses based on current overall tissue loading and fudge it.. The more Helium in the mix the more iffy the guess gets. I remember a 40m dive last year that I was watching the VR3 when it when from 5 minute no deco, to 10-15 minutes deco(dont remember exactly - my explorer already had a 3m stop)) while I was watching the display! now is that useful??
Maybe some mathematicial will approach this solution in the future but so far none have.

running through the way ascent times are calculated, a similiar approach would have to be done to calculate ndsl, but done as test ascents until a stop is actually necessary.. this takes lots of computing time especially on bubble models like the explorer..

Most surfacing times are calculated in the background because it takes processing time.. as the loading increases so does the delay.. none of the computers update in real time these schedules.. That the reason why you may see at one point say 2 minutes remaining , and all of a sudden (much less than two minute) you are clear.

[madmole]

The VR3 is a bit of an exception as it is not a time constant computer, Thats why it has a time bar across the top so you can see the speed of time.

Having hacked some Suunto and Alladin computers eeproms I pretty confident that they do all the nescessary calcs in real time and dont use variable time

Certainly its programmably possible (and easier) to wite a constant time deco computer that can do mixes and show surface and NST times as confidendtly as it shows tissue saturation etc. Assuming you understand that the model is making the assumption that you will stay at that depth and on that mix or that you will accurately follow its surfacing profile and gas changes

For example. If you look at a Buhlman compartment and its been 1 second since you last examined it and you know its absorbtion paramentes (M values) and the current pressure, PO2 Phe etc, then you can calculate the increase in stauration of that compartment. Its pretty easy to also ask, well if it increases that much in this second, how many seconds till its saturated. Do this for each compartment and the shortest is the NST. OK this is a simple Bulhmann example but its just as valid for other models
The VR3 may not be perfect but I personally do find its NST and TTS display very usefull. As a large % of my dives are 40-50m I'm got in the habit of just swimming around until Dave and me just cant face the mounting TTS anymore