Quick test of a tiny QEV cannon firing air at 12atm, viewed through a Schlieren setup (no razor blade). 1/8th speed (15fps) and improved video performance because somehow Youtube cropped the last frames of the other videos (?) I didn't quite understood the need for a razor blade but without one I still see the flow of air. For me, the razor blade just makes the dot of light smaller(?) If anyone can clarify me what the razor blade really does and where it should be placed (in the source of light or in the camera) I'd really appreciate. Also important to note that this is AWESOME to look with the naked eye but almost the dimmest light can blind you. I covered a tiny LED torch with aluminum foil and punctured a hole with a sewing needle, on the side! so that the LED doesn't bright directly through the hole. Take care with the eyes!!

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Just to prove that I'd done it, I recorded the moment I got the third sail up on my tod. As I say in the clip it may only have been 4 knots and the fenders were still out but it was quite an achievement for someone who has only been sailing for two years. I particularly like the shot of the bike chained to the mast! [] www.followtheboat.com [] * tales from the high seas *

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It is a simple but very useful idea. A weak light, for example for orientation at dark moonless night. The circurit is as simple as possible. It includes all the calulations. The way of creating it makes it a very useful part. And its done very fast. Just a small part of a perforated circuit board, 2 parts and some soldering.

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