Good idea for optical hi-hat

[Sylv1co]

Hi,
A optical hi-hat may be difficult to set up and may have wrong behiour when the top cymbal shake,this because of the piece that gradually hide the light of the led.
We can replace this piece by a gradient from black to white printed on a transparency film. So this film will be fixed on a piece of transparent DVD box glued to the botoom of th tilter.
Have a look to the pdf

dégradé.pdf

and to the pictures: [img][img]http://i.imagehost.org/t/0417/DSCF1864.jpg[/img][/img][img][img]http://i.imagehost.org/t/0532/DSCF1863.jpg[/img][/img][img][img]http://i.imagehost.org/t/0713/DSCF1862.jpg[/img][/img][img][img]http://i.imagehost.org/t/0761/DSCF1861.jpg[/img][/img]

[Sylv1co]

A small video will maybe be clearer...
http://www.youtube.com/watch?v=gWZCclA_WBc

[jman 31]

Looks good. Keep in mind though that typically most drummers don't let their hats travel more than about 15mm before fully closed. I couldn't tell on yours, but it seemed to be much more than that.

[Sylv1co]

In fact, I've set this Hihat to have CCO4 127 when top cymbal is about 15mm over the bottom cymbal (CC04=0 when fully closed). If the top cymbal is 40mm above the bottom cymbal, it's the same result, CC04 will began to decrease when space between them will reach 15mm because the rest of the transparency film is black and so it don't let pass the light.
I can set the overall range by choosing another height of the gradient from black to white (see the pdf). I've try different kind of it (I've just streched a gradient in MS WORD) before find the good one. I can also set the CCO4= 0 level with a variable resistor in serie with the LED.
To my mind, the intersets in this kind of optical hihat is first that we can set it just by strecthing or reducing a gradient from black to white (it cost me 70 cents of euros to print the entire page of gradient in my local shop), second that a shake of the hihat stem have almost no impact on the CCO4 level.
In other projects, it also allow you to have a high overall range (10 cm isn't a problem, just strech the gradient in your favorite word processing software and print it on a trasparency film).