Hi All, I've been working on it for quite a long time now, and I managed to break 3 flashes until now, but now it is 99% working, so I'm happy to share my DIY.
So I have the Olympus OMD EM1, with the Olympus housing, I wanted to have a Led trigger, that will NOT have batteries (powered from the camera) and will work with TTL and I will be able to adjust the intensity from the camera itself.
So It wasn't easy... I have to research a lot of LEDs different sizes colors and wavelengths, wanted it to work with any fiberoptic out there... not to have to change anything in my setup.
So to make a long story short, it is working!
I will share the process in general now, and then I promised a good friend to do the same for him, so during that, I will upload some more detailed process.
the process was to take an FL-LM2 (Olympus original flash) I bought few of those cheap online:
took it apart, and then with the help of this post:
I changed the capacitor to a 1uf, removed all the flash tube board.
Now the 5V that I get from the camera is from the accessory port, I knew which pin is the 5V, so I connected a wire to the 5V pin, now that I have 5V and LEDs, all is left is to trigger them.
LEDs that worked the best for me where (believe me it wasn't easy to find the correct LEDs that will work every time):
then I disconnected the 750K ohm surface mount resistor (marked as 753 on the board). and connected the negative of the LED to the IGBT marked as p4006 on the board.
so Yeah this is not the best way to light a LED 5V and high current, but since it is very very short pulses it is fine.
Now the LED were working good, but when I put them back in the case and the housing it wasn't firing, the distance + the reflective sticker in the housing and the fiberoptics had too much attenuation and it didn't fire the flashes.
So I have to 3d print a part, to have the LEDs placed inside the housing in the correct place, and now it is great!
I will upload the detailed how to when I will make a new one + the STL of the 3d printed file so anyone could do it.
In the end, the cost to do so will be 30$ flash, 6$ for 100 LEDs, time and a 3d printer.
I'm attaching a photo of how it looks + a video of the final result.