Shearwater HUD on classic Inspiration

Johnny Christensen

As a photographer I often have my hands full, while underwater. There is too much stealing my attention, trying to compose a nice picture, maintaining trim, directing the model, getting the job done before bottom time runs out.
That means that in reality I shouldn’t be diving a eCCR, as these things are taking away the time I should be spending checking the displays, making sure the yellow box on my back is not trying to kill me.
I admit it, when shooting pictures I have relied too much on listening to the oxygen being injected. And that point has always made me a little uncomfortable. As I see it, it's not a matter of if, but a matter of when the electronics decides to quit working in the middle of a dive.

That means I have been in the marked for a HUD for quite some time. But I wanted one that would do a little more, than just tell me that things are generally good or alert me to the fact that I need to do something now.
I wanted a hud that would tell me the PO2 as well as making me aware if some of the cells did not track properly.
Spending some time here on RBW can be really useful, as Bruce Partridge announced the Shearwater HUD was now shipping and in the following discussions it became clear that using it with the Beanie 4th. cell holder, it would work on the classic Inspiration.

I liked his design and the logic behind it. You can read more about it here http://www.rebreather.ca/products_hud.htm
And here
http://www.rebreather.ca/products_insp_hud.htm

So I went ahead and placed a order. And of course also ordering a Beanie 4th. cell adapter so I could get the wiring into the Inspo lid.

Fitting it was really straight forward. I elected to have the cable coming in from the left side of the Beanie adapter, to avoid it being in the way, when you are connecting the oxygen feed to the solenoid.
The wires connect to the existing molex plug, the white (or yellow) wires are ground, and they connect to the blue wire on the plug.
The other colour codes for the wiring are.
Sensor 1 - Brown
Sensor 2 - Green
Sensor 3 - Grey

If you fit a small length of heat shrink tubing to keep the wires from moving, it will make the cables more rigid and require a bit more fiddling to put the whole sensor arrangement back in the Inspiration lid again, but it's worth it IMHO.

I placed the small electronics box wedged in between the oxygen feed hose and the Inspiration casing. Trying to avoid placing too many things externally on the box as I'm primarily diving wrecks.

The HUD display itself, can be fitted in the Vision HUD holder, with just a bit of an old cut-up low pressure hose around it. Simple, yet effective

I did a 2½ hour night dive to test how I liked it...and I absolutely love it.

Attached Images

	Electronics.jpg (58.6 KB, 452 views)
	HUD.jpg (34.4 KB, 451 views)

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www.johnnychristensen.com
Wreckphotography from the cold north

Beanie

Nice

I'm in the process of getting one.
What's it like to dive?

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Beanie
Gallery Admin & Library Assistant.
www.outlawdivers.org.uk
www.beandiving.co.uk
www.beanengineering.co.uk

Johnny Christensen

It's great, now you have the most important information right in your face. I'm sure that some day, it may save me from terminal PO2 problems.

I'm using the medium lenght HUD arm and bending it slightly forward, to get it further from my eyes. Too close and I can't focus on the lights.
Even when you can't focus a hundred percent on the lights, there is no problems telling whitch sensor is not tracking.

And I found out last night, that I have a 1½ months old Teledyne sensor that is current limited. 10-15 minutes after it was calibrated it started showing 0,1 -0,2 less than the others. So I tested it with a PO2 range from 0,4 to 2,0. At PO2 2,0 it showed 1,46.

It's very fast to spot when the cells are acting up.

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www.johnnychristensen.com
Wreckphotography from the cold north

SimonK

Johnny

Can you give some more detail on how you connected to the cells.
I have a shearwater HUD waiting at home. I am thinking of building some Y piece cables so I don't have to change the standard loom.

Simon

Beanie

That's what I was thinking Maplin sell them for a few £

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Beanie
Gallery Admin & Library Assistant.
www.outlawdivers.org.uk
www.beandiving.co.uk
www.beanengineering.co.uk

Johnny Christensen

I just followed the instructions on the Shearwater site.
Shearwater Research Inc. - Computers for open ciruit and rebreathers

Basicly just putting the new connector in together with the existing one so it rides on top of the other. After a few attemts you get the feeling for how it's done when it locks on. There is no need to change the existing loom. Should you deside that you don't like it anymore or the head maybe going back to APD for service. Simply remove the heat shrink tubing, pop the connectors out and you have a original unit again.

Even with the new SMB connectors, I guess you could make a Y piece cable, that would allow you to add a Shearwater HUD to the unit. Will take a little longer to do, but should be relatively easy.

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www.johnnychristensen.com
Wreckphotography from the cold north

SimonK

So you are jamming two crimp contacts into one hole? Not sure I like the idea of that but will have to have a play when I get home. Probably one of those things that is easier to do than write about.

Simon

Johnny Christensen

Yup, that's how Bruce designed it
Y split cables may work better?? But it is easy to change if I deside that's the proper way to go.

__________________
www.johnnychristensen.com
Wreckphotography from the cold north

SimonK

I have now got a shearwater HUD and Beanies adaptor, two very well made bits of kit.

I wired up the HUD a per Bruces web site by pushing the HUD cimps in behind the standard controller connections



This works OK and should be secure enough if you add some heatshink to hold it all together.
I decided I wasn't 100% happy with the arrangement so built some Y piece breakout adaptors. The photos below show how I went about it.



a collection of bits








The Y piece showing the HUD cables connected



everything assembled (yes I know HUD lines are in the wrong sequence)



I think the cable routing needs a bit of work.


One side effect is that the AP loom is now protected from the moisture in the head.

Beanie has identified some off the shelf Y pieces from Maplin that should do the same thing.


Simon

Padowan

I fitted my HUD a few weeks ago, and I used the method Bruce suggested. The reason I did it this way, rather than using some Y-Pieces was that I did not want to introduce another mechanical joint and therefore failure/resistance point into the control loop.

By using Bruces method, the wires from the cells to the junction box remain unbroken and with no joins in, and therefore if anything is likely to fail it will only be on the HUD side, not anything related to control.

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