[PSUBS-MAILIST] USB thru hull

Fri Dec 1 04:19:46 EST 2017

That's interesting Steve.
just found this paper on data & power transmission through metallic walls....
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4721790/#!po=10.1563
It is a reasonably easy read compared with some technical papers.
I wonder if you could have a fibre optic type signal going through a view port,
then use the copper wire interface that telecommunications companies use.
Forget the proper name for it!
For things like Brian's camera gimbal & Hanks electric manipulator  etc you
could have a power + & - through hull running to an external junction box, 
with these devices connected & then switched on by an optic signal through the
view port. That would save loads of through hulls.
Alan

Sent from my iPad

> On 1/12/2017, at 9:37 PM, Stephen Fordyce via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi Brian,
> Could you use a wireless USB connection instead?  I'm not sure of the exact product, but surely something exists with the functionality of a USB cable, but with a wireless signal instead of the cable.
> 
> Various wireless signals will get through plastic, short hops through water and sometimes even metal, which rather surprised me.  I've had weak Bluetooth signals go through 6mm acrylic plus 1-2m air, and through 3mm aluminium + 5mm water + 1m air.  You would have to have the outside half of the wireless hardware pretty close to the hull (maybe at a viewport? or at a port with a solid plastic plug) but then you could run a wire from there to the camera and dispense with a penetrator into the camera housing.  Might be  worth considering when weighed against everything involved in a penetrator.
> 
> I also did a USB (2.0) potted (but unshielded) wired connection for my pressure pot.  It was noisy enough that the very crappy webcam I installed inside struggled to get the signal through properly.
> 
> Cheers,
> Steve
> 
>> On Fri, Dec 1, 2017 at 7:20 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Thanks Sean, Alan,  I've just been recently amazed how there are so many options now with usb and HDMI that it could be a good way to control stuff outside the sub , like panning the camera for instance .  But you could have a myriad of different controls as well.
>>  
>> Brian
>> 
>> --- personal_submersibles at psubs.org wrote:
>> 
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
>> Subject: Re: [PSUBS-MAILIST] USB thru hull
>> Date: Fri, 1 Dec 2017 19:28:22 +1300
>> 
>> Brian,
>> just another thought on this. 
>> G.L. ( now DNVGL) require that through hulls
>> don't leak if the cables are chopped through or cut.
>> So I can't see any other option than potting if you want to comply with
>> that. If you wanted to go this route, perhaps a stepped adapter like this
>>  https://www.titanfittings.com/product-p/ss-6404.htm
>> would give you enough room to separate out the component wires & sheilds
>> & allow you to pot them.  Have been doing a bit of potting lately & not always easy.
>> Have some thoughts on how to go about potting if you need to hear them!
>> Alan
>> <image1.JPG>
>> 
>> 
>> Sent from my iPad
>> 
>> On 1/12/2017, at 3:59 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Alan,     That was my thought and fear exactly !    I'm probably over thinking this as I usually do.  I will probably be wanting to do the same thing to an HDMI cable.
>>  
>> Brian  
>> 
>> --- personal_submersibles at psubs.org wrote:
>> 
>> From: Alan via Personal_Submersibles <personal_submersibles at psubs.org>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
>> Subject: Re: [PSUBS-MAILIST] USB thru hull
>> Date: Fri, 1 Dec 2017 15:37:14 +1300
>> 
>> Brian,
>> can you find a cross sectional diagram of the wire you are talking about?
>> Have attached one I found on line as an example. Looks a nightmare to pot.
>> This item has a plastic jacket & could be put in a compression fitting,
>> however I would do what Carsten & Emile have done & put a blue globe
>> fitting on the inside of the hull as well as the outside.
>> My only reservation about this is that depending on how the wires etc are
>> arranged inside the jacket, it could compress unevenly. You could try & fill
>> the area of the cable that is inside the compression fitting with expoxy by
>> cutting into the jacket & shielding & squirting a low viscosity epoxy in there.
>> Alan
>> 
>> <image1.JPG>
>> 
>> 
>> Sent from my iPad
>> 
>> On 1/12/2017, at 2:28 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Sean,   I'm using and squeeze fitting now for a co-ax line that is good for 600 ft, but there is a plastic core in there that the squeeze fitting can press against,  with regular wire it seems like water might try to migrate through.
>>  
>> Brian
>> 
>> --- personal_submersibles at psubs.org wrote:
>> 
>> From: "Sean T. Stevenson via Personal_Submersibles" <personal_submersibles at psubs.org>
>> To: personal_submersibles at psubs.org
>> Subject: Re: [PSUBS-MAILIST] USB thru hull
>> Date: Thu, 30 Nov 2017 20:21:23 -0500
>> 
>> No, I meant that the shield should be contiguous from start to end, regardless of how many connectors are in line.
>> 
>> Sean
>> 
>> 
>> 
>> Sent from ProtonMail mobile
>> 
>> 
>> 
>> -------- Original Message --------
>> On Nov 30, 2017, 18:18, Brian Cox via Personal_Submersibles < personal_submersibles at psubs.org> wrote:
>> 
>> Sean,    So not necessary to have the wire shielded through the short thru hull area?
>>  
>> Brian 
>> 
>> --- personal_submersibles at psubs.org wrote:
>> 
>> From: "Sean T. Stevenson via Personal_Submersibles" <personal_submersibles at psubs.org>
>> To: personal_submersibles at psubs.org
>> Subject: Re: [PSUBS-MAILIST] USB thru hull
>> Date: Thu, 30 Nov 2017 20:12:22 -0500
>> 
>> Yup. +5V, data+, data-, and ground. Any 4 pin connector should work, but to avoid noise issues you'll probably want to use twisted pair shielded wire, carry the shield through the connector, and depending on the total length of the cable run, 28 to 20 AWG wire (0.81m to 5m length, according to USB 2.0 spec).
>> 
>> Sean
>> 
>> 
>> 
>> Sent from ProtonMail mobile
>> 
>> 
>> 
>> -------- Original Message --------
>> On Nov 30, 2017, 18:03, Brian Cox via Personal_Submersibles < personal_submersibles at psubs.org> wrote:
>> 
>> Hi All,
>>                Has any one ran usb cable thru the hull and out to a camera or other device?  I think it's just 4 wires. 
>>  
>> Brian
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