www.megadrum.info

I put this together for someone that was looking for an optical variable trigger to work with acoustic hi-hats conversion. It is based on Dmitri's schematic. No alterations need to be done to the hats except for running the wire, although that could go out between the two hats if you are a purist that doesn't want to mess with you pretty hats. It is being tested over the next few weeks and I (or the person I sent it to if they are so inclined) will let you know how the results turn out.

You can see bigger, clearer pictures HERE

Grats! Looks great!

I would imagine the angle of the 'metalblocker' is what defines the physical heigth difference between open and close (the function served by the clutch when playing purely acoustic). There could be a need for an adjustable blocker, where the angle can be user-defined, like the acoustic clutch is.

I'm also curious to how you dampening the acoustic sound coming of this hybrid, so it doesn't contradicted the e-hat.

Thanks man,

I haven't done any dampening. That will be up to the user to determine how they dampen it. The Optical blocker is just a piece of light gauge galvanized sheet metal. It will definitely have to be adjusted as per the user. It cuts easily with a pair of tin snips. You would have to take a little at a time until you found the right setting for your particular needs. It could easily be replicated by someone if too much was removed. The picture shows a setting of about 3/4" (19mm) between the hats. I would guess for most that is a little too much, but I would rather start with to much and back it off than be short from the get go.

J

jman-
How do you keep the top PVC with the metal block from spinning? In the original design the metal fit into a slot in the outer (lower) PVC, but this doesn't appear to be the case in your design.

By the way I really like 2 things about your setup: 1. the components are all board mounted, and 2. The enclosure around the LEDs looks like good protection.

Have you thought about how you will pass your cable through to the outside of the hithats?

Thanks for the comments Thurston. If you look real closely at the intermediate part. The small black one, there is a slit in the side of that. That has a flat side that goes up against the circuit board that keeps it from moving. I am currently in the process of fabricating one that I even like better than this. The person that I sent this one to had a smaller area to work with and the hats wouldn't even come close to closing all the way. I will post pics as soon as I get through with the fabrication.

The only way I can see to get the cable out is to 1. drill a hole in your bottom hat, 2. let them run out the back, between the two hats. I don't really know any other way.

HERE is a link to some bigger pictures and you will also find my circuit board on this site. You will have to register to view them.

I threw together a strip board layout today just for the hell of it. It is not verified yet, but I'm pretty sure it's correct. If anyone wants to check my work, it's based on Dmitri's schematic.

Keep in mind that the white square with the red dot is a cut point. There are cut points under all of the components except the emitter and detector if you look real close.

Dmitri,

Will this emitter/detector switch work with your optical hat schematic? I would think it would, but since you did the math for the schematic, I thought I would ask.

Thanks,
Jman

Don't see why it shouldn't. Just make sure that the light blocking is indeed very gradual with this type of a phototransistor.

dmitri wrote:Don't see why it shouldn't. Just make sure that the light blocking is indeed very gradual with this type of a phototransistor.

Thanks man.