DIY fiber optic writeup with parts

11 hours ago, Kraken de Mabini said:

I bent my Toslink f.o. cable in a 90 angle, dipped it for 5 seconds in boiling water, then cold water, and the 90 bend became permanent.

 

That sounds like an interesting solution and avoids the cost of right angle plugs as well as the requirement for more expensive cable to fit into right angle plugs. What minimum bend radius did you achieve?

According to Eska (who make 1.5 mm fiber optic fiber) the minimum bend radius for a 0.5 DB loss (about 60% if I remember how to convert dB to percent) is 40 mm so quite big. For the 1 mm fiber it is 25 mm.

So not so small. 

Bill

The radius depends on the outer diameter of the Toslink cable. With 4 mm cable the radius of the right angle is about 15 mm, and with 1.8 mm cable it is about 8 mm. I bend the end of the cable into a U shape, dip the bend in boiling water for about 5 seconds, then promptly dip it in cold water.. Once cool, the right angle curve enlarges a bit, but when plugged the bend still keeps the cable near the strobe or housing.

This simple approach saves the trouble and cost of using a right angle plug. It is important to keep the time the cable is in boiling water to a few seconds to not damage its light conduction. 

At the weekend I was asked if I could do some testing of strobes using TTL settings. This lead to a slightly sobering lesson or two which I'd like to share with you guys.

I've posted before that

a). I use a pair of scissors to cut fibre optic cable; and

b). that I use the Inon double-hole plugs to plug the cable into my strobe (with Howshot L-plugs at the housing end); and

c). that this method has worked perfectly with my strobes.

And now for the salutary bit: yes, works perfectly on Manual - but maybe (maybe) not so good on TTL. Or maybe not at all.

I learned two things: if you cut fibre optic cable with a pair of scissors there is a real risk that you create a non-flat cut on the fibres which can reduce light transmission.  Ideally a "flat" cut is needed which can be produced with a "Stanley" knife, box-cutter type blade.

Then, the Inon bushes have two entry holes for fibre cables. By their design they are both "off-centre" from the centre of the bush. This means that the light transmitted through the fibre may well not hit the exact spot required on the strobes sensor. I now understand that 1-2mm can make a real difference.

Result: the combination of off-centre and possibly slightly reduced light transmission, whilst generally not an issue for Manual settings, can indeed be a problem for TTL which, I now understand, needs a more sensitive and accurate setup.

A number of WP members with superb technical knowledge have raised these issues (take a bow, guys) before and I read them with great interest. But at the same time, I no longer used TTL, I knew what worked for me and was happy to pass on my own field experience. 

I now appreciate even more that "a little knowledge is a dangerous thing" and what, on the surface, may seem a good solution can lead to covering a problem which might occur later with a slight change of system.

The discussions over the weekend drew out that sometimes when users complain they cannot get strobes to fire correctly, the problem may not necessarily be in the main equipment units themselves but possibly something as simple as how a fibre optic cable has been cut - or the way a cable aligns with a sensor. Or a combination of all of the above which leads to sufficient light transmission degradation to lead to apparent failure.

Happily resolving a lot of these issues is relatively straightforward. Mr Stanley and I spent a half hour disassembling fibre optic cables, re-cutting them and re-assembling......

A lesson learned........

Let me add a footnote:

During the testing I could not get the strobes to fire in TTL mode with scissor-cut fibre optic cables. But they were perfect in Manual.

I re-cut them using a Stanley knife and have just re-tested them. Presto, the strobes now fire in TTL mode!

11 hours ago, TimG said:

Let me add a footnote:

During the testing I could not get the strobes to fire in TTL mode with scissor-cut fibre optic cables. But they were perfect in Manual.

I re-cut them using a Stanley knife and have just re-tested them. Presto, the strobes now fire in TTL mode!

 

The manuals for the INON optical cables include information about cutting and maintaining cables.  Here is a link to one of the manuals:

http://www.inon.jp/pdf-dl/_userdata/manual/00_strobe/0321_manual_optical_d_cable_ss_type_l_en.pdf

They recommend a sharp Stanley knife to cut the cable.

Has anyone seen an Inon-style fibre optic rubber plug that only has single, central hole? - see image

Inon sells a plug with two holes - but I'm looking for a single, central hole plug. 

Thanks!

Haven't been able to find a straight plug, but INON make a single hole "L" plug:

https://www.backscatter.com/Inon-Single-Hole-Rubber-Bush-Type-L

I also found that I could use toslink plugs in S&S connectors, just need to shave a little off the corners of the square plug.  Not sure how readily available they are - I found one here: 

https://www.ebay.com.au/itm/154965258419?hash=item2414a630b3:g:T6EAAOSwFqJWtGLm

Thanks, Chris!

Yeah, I'd seen the Type-L plugs (I use the Howshot ones) but they are a bit awkward to use on the back of some strobes (ie Retra) and I was trying to find something like the Inon double hole bush one but with only one hole. Apparently Olympus used to have them some years back and I found a pic of one online but can't find them googling around.

I hadn't thought of the Toslink connectors - but worth an explore: thanks.

20 minutes ago, TimG said:

I hadn't though of the Toslink connectors - but worth an explore: thanks.

 

Yes, they won't fit out of the box, but if you use a stanley knife to shave down the corners of the square section they fit the sockets on my Nauticam housing just fine.

Oskar of Retra has just pointed me (many thanks!) to ones they have used::

https://www.backscatter.com/Olympus-PFCA-03-Optical-Fiber-Cable-Adapter

2 minutes ago, TimG said:

Oskar of Retra has just pointed me (many thanks!) to ones they have used::

https://www.backscatter.com/Olympus-PFCA-03-Optical-Fiber-Cable-Adapter

Nice, the stores don't make them easy to find some times, just for fun I went to find it from the menus 5 minutes later found it buried in compact- other accessories

Agreed, Chris. They sure don't. I was poking around the Divervision website last night and found it hard to even find the Howshot ones they sell!

Life eh? Tsk......

+1 on the Inon L shaped single hole plugs quoted by @ChrisRoss - I am using these as well, very well made and easy to assemble/disassemble if needed. You could try to "straighten" them out, as the rubber thing, that the cable goes through, is very flexible and comes out, so you could make some 3d printed clips or just wrap it with tape so it sticks to the cable.

Onderwaterhuis in NL has them for 7.20 Euro
https://www.onderwaterhuis.nl/catalogsearch/result/index/?f=Inon+Single+Hole+Rubber+Bush+Type+L&q=Inon+Rubber+Bush+Type+L

Have not found yet the perfect method of cutting the cables, as sadly my friendly fiber optic network company refused to let me use their fancy cutting machine as apparently its for solid core only, but so far had good results using good quality "manual" cable cutting tool, then sanding the end of the cable with very fine sanding paper - I've used a 1000 grit one.

Thanks, makar0n. I did wonder about just using the rubber bush out of one of those. I'll give one a try using the ones in the Howshot version - which is the same thing only with one fewer screw......

I really like the L-shaped for the housing end of the cable but, as I wrote, I don't find it so convenient at the strobe end.

One can also use Uxcell bushings, sold by Amazon:

Uxcell® 20pcs 27mmx7mmx4mm Micro Strain Relief Cord Boot Protector
https://www.amazon.com/20pcs-27mmx7mmx4mm-Strain-Relief-Protector/dp/B00XBG5U82/ref=sr_1_15?crid=1XAD54U9I1WWN&keywords=uxcell+Rubber+Strain+Relief+Cord+Boot+Protector+Sleeve&qid=1657125310&sprefix=uxcell+rubber+strain+relief+cord+boot+protector+sleeve%2Caps%2C118&sr=8-15
(The 27 mm is the plug's length, 7 mm is the plug's o.d. and 4 mm is the hole diameter)

 One gets 20 pieces for the same price as one rubber one.   I glue the fiberoptic cable into the bushing with ABS plumbers cement from the hardware store, then cut the end with a sharp Gem type razor. 

6 minutes ago, Kraken de Mabini said:

One can also use Uxcell bushings, sold by Amazon:

Uxcell® 20pcs 27mmx7mmx4mm Micro Strain Relief Cord Boot Protector
https://www.amazon.com/20pcs-27mmx7mmx4mm-Strain-Relief-Protector/dp/B00XBG5U82/ref=sr_1_15?crid=1XAD54U9I1WWN&keywords=uxcell+Rubber+Strain+Relief+Cord+Boot+Protector+Sleeve&qid=1657125310&sprefix=uxcell+rubber+strain+relief+cord+boot+protector+sleeve%2Caps%2C118&sr=8-15
(The 27 mm is the plug's length, 7 mm is the plug's o.d. and 4 mm is the hole diameter)

 One gets 20 pieces for the same price as one rubber one.   I glue the fiberoptic cable into the bushing with ABS plumbers cement from the hardware store, then cut the end with a sharp Gem type razor. 

 

 

 

 

I have tried those out and they do work. They are very soft and pliable however, and I don't think they get as good a seal as a solid plug. I even had to wrap the fiber with electrical tape to make it stiff and full enough to hold in place. I have concerns about the durability over time.

I suggest either reusing an old connector and drilling it out or getting one of the purpose-built plugs online. 

I have used the Uxcell plugs for several years with no problems.  The ABS plastic glue is necessary to fill the gap and secure the fiber optic cable to the plug, and also to stiffen the assembly into a secure unit.  
Once the ABS dries, the plug is cut with a razor to a length of about 8 mm. 

This photo shows the ABS glue, Gem razor, cables and Uxcell plugs, they are all it takes to produce a completed fiberoptic cable with plugs. I do not recommend wrapping the cable with tape as the tape may come loose or slide inside the plug; ABS cement provides a secure and permanent bond between cable and plug. Notice the plug is cut to a length of about 8mm (excluding its wide top part)

Those look like quite thick cables, Elias? Much thicker than the 617 type?