Budget DIY strobe?

I have an Olympus TG5, and to buy an Olympus Strobe would cost £379 plus £104 for a short arm and another £109 for a fibre optic cable.... a total of £592 for the full set up.
A more reasonable Sea and Sea Ys-03 option is still £325 for a kit.
But eBay will sell me a range of Speedlight clones from £22 up or a WS18 basic flash for a tenner, so can we make a DIY option?

I think yes, but would be keen to hear from anyone who has tried, or has any hints or ideas for me.

I did look at DIY bendy arm options, but decided that I already have a perfectly good and very adaptable arm hanging from my shoulder which can hold a single strobe at more or less at the perfect position.
The fibre optic cable takes a trigger flash and sends it round and round to a light sensor, but light travels happily in a straight line, so if we just turn the camera flash through 90 deg with a postage stamp sized mirror clipped to the housing, we can send it straight to the strobe held in our hand above or to the side of the camera.
I have already tried (in the dry) mounting a small mirror in front of the flash and this works well with a Speedlight I have (a YN560 which has a good flash sensor) and also with a WS18 which came with a poor sensor but now works well with DIY phototransistor set up.
So the only tricky bit is a housing for the flash unit which could be made in a variety of ways; and, considering the price of the flash unit, a possible leak would not be so great a disaster.
The benefit to me, besides cost, would be that I would not need to tote around a full rig, but could hang the flash off a shoulder D ring, which is where I hang my camera when not in use.

With lockdown, diving may be a way off so I have to have something to keep me busy. Anyone inspired or with ideas?
Rod

Only concern with a leak is that the flash is up to 400VDC ... and salt water tends to be conductive. Not much stray voltage should get outside the box as there is no real "path" but could be concerned if holding it.

- Buy defected light with good condition housing , put inside normal strobe without housing

- just use hi power scubalight with difuser , battery will hold short exposure times

- repair scuba strobe ; lot of scuba strobes for low price ;

https://www.ebay.com/sch/i.html?_fs...sacat=0&_from=R40&rt=nc&LH_ItemCondition=7000

https://www.ebay.com/sch/625/i.html...=0&_sop=15&_oac=1&rt=nc&LH_ItemCondition=3000

To answer my own question, here, briefly, is what I did.

The Metz 44 AF-1 flash for Olympus/Panasonic has an IR receiver which will not only synchronise with my TG5 but in RC mode will actually give TTL metering. It is also small enough, with a little butchering, to neatly fit inside the housing of an old UK600 torch. A small window cut in the rubber cover allows the flash signal to reach a visible light photo diode and some basic electronics transfers the light pulse to an IR LED within the housing. In its simplest form, turn on the unit and put it in the housing just before you dive, the standby current is very low.

I have incorporated the mirror I suggested into my macro ring light. You could remove the diffuser and make whatever suits your skills reusing the available screw holes

I am not going to give blow by blow instructions unless someone asks, but I have achieved my objective of a (powerful) TLL strobe for about £30 (and quite a bit of waiting for listings on eBay plus some bits in my box).