The kit will be slightly more expensive than the present one. It will also be available pre-assembled. I am also planning several new projects, which are being prototyped at the moment. It is useful to trigger a slave from a flashgun mounted on the camera, but you might not want the foreground to be illuminated. The visible light can be blocked using an infrared filter.
Flashguns generate a significant amount of infrared light.
This is detected by the slave and triggers the main flash. Usable underwater The photodiode is sensitive to visible light as well as infrared. The slave is triggered by the short, sharp, bright pulse from an electronic flashgun. It should not respond when a caplamp is shone at it. Not adversely affected by ambient light Cavers will usually be operating the slave unit in the dark, so the question of ambient light does not arise.