Fibre optic tether

[rossrov]

That is a very informative post rovdude. I have not seen anyone on the Internet list as specifically as you have done here. The module sockets I had a bit of trouble finding and when I did they were more expensive than your source. Microscopes I looked at were hundreds of dollars, and was going to try to get by without. For $70 or so this would be a must-have.
As discussed earlier in the thread, the direct connection to the module will present challenges. That's OK as long as nothing gets blown up, so be careful with the power supply connections, and, as hobbydude says, the radiation.

[rovdude]

Also forgot to mention, the epoxy is heat cure. I don't want one of those specialized ovens for hundreds of dollars, so I'm probably just using a hair dryer for a few minutes. If that doesn't work, I'm going to toss the connectors in the oven on preheat for a few minutes.

There are too many unneccesary specialized over priced tools for fiber optics, so I tried to cut those out of my process.

For powering the transceiver, I'm just using 3.3V Reglators connected to the Arduino's 5V output. The 3.3 on Arduino can't supply enough current to power the transceivers, but the 5V can.

[hobbydude]

Good to see progress with your tender. I was interested in the waterproof tender connection type. Thanks for posting the link. IP68 spec too. I like the idea of having a commonly available connector within the waterproof housing.

If you are going to work with SFP's you are limited to LC and MTRJ connectors with LC being the more robust option allowing up to 3mm sheath.

SFPs are not as robust as a small media convertor and not very tolerant of running out of supply spec 3.3v. Sounds like you have it sorted via 5v rail on controller. SFPs are most commonly installed into ports on switches and routers.

Most small media convertors such as this onehttp://www.dna.com.au/Products/MiniMc-E ... Converters run on 5-20v @ less than 1amp so small $5 UBEC will easily run. As you say transceivers and m/c are basically the same thing. Not relevant to ROVs but the determining factor of what to use is Power over Ethernet related. A/C type or chassis type are used if equipment requires PoE, 48volts at higher current rating.

“Thanks for the safety tip, honestly wouldn't have thought about that!” I had a look at the SFP you linked. It is low power 1310 range. Be careful with 1550 and above.
If you are buying a Microscope make sure it has the 2.5mm adaptor. You generally buy the pen style which slides over the connector end. Most are 3.5mm, LC is 2.5mm. The key with fibre is to make sure you connections are spot on, as in the gap between each end when joined and that you polish a perfectly flat fibre. A long polish does not mean a flat fibre as glass does sometimes break away on the edges given reflection/loss. Microscope is the only way to check. Worth it when you get it right.

There is a fairly new product I was told about that is basically a fibre/copper hub, one fibre port in, 6+ copper out so designed around new modular design office builds. If this was affordable it would be a good option for multiple IP items.

[hobbydude]

Also forgot to mention, the epoxy is heat cure. I don't want one of those specialized ovens for hundreds of dollars, so I'm probably just using a hair dryer for a few minutes. If that doesn't work, I'm going to toss the connectors in the oven on preheat for a few minutes.

Just let them cure overnight. Best not to apply uneven heat or move them around when not set

This is one of the best general fibre information sites http://www.thefoa.org/tech/ref/basic/term.html

For short patch leads it is a better option to spend $15 on a pre made tested lead someone has made with all the expensive tools Every patch lead need to be tested and documented with a serial number before it can be sold. It will include a report with IL insertion loss and RL return loss for each fibre end point. I assume you will need a short lead at each end of the tender line so this will cut down on the loss from the 4 joins.

[hobbydude]

This is what I was refering to as an on board option if you want to just run multiple HD IP cameras and controller for example.
No seperate SFP or switch required. Runs on 12volts. MM version cheaper.
http://planetechusa.com/isw-511s15-indu ... se-fx.html

[rossrov]

Wonder how much $ and where to buy? http://www.voscom.com/video-ptz-over-fiber-1v1dd.asp

[Jaman42]

I bought a similar from www.chipshine-tech.com, 1-channel video and bi-directional RS485 over one single-mode fiber. I haven't had the chance to try it out yet cause I haven't received my fiber optic cable.

The pair cost me 71 USD + shipping

I will post a review once I get the chance to try it out

[rossrov]

Thanks for posting that. Previously the thread has looked at similar and it seems there are a number of these that appear to do bi-directional data, but in fact are only one-way. I may have been looking at a different one to yours on the Chipshine site. Under the specs tab I couldn't see any mention of bidirectional, only "reverse"?

[Jaman42]

Yeah but they customize it after your needs. Mine have four wire rs485 so full duplex. You can for example also add a audio channel if you like.

[rossrov]

Ah-ha! Interesting. A while back I contacted who may have been a reseller of that gear. They had an elaborate ordering code where you could put together all sorts of options. I requested a very simple video and two-way data set. Nothing forthcoming.

$70 a set, add some connectors and cable and that would be a wonderful tether solution. Keen to see you get it going