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Home DIY Electronic Drums Sensing The Vibes

Sensing The Vibes

I know it has been awhile since my last post, but I have been testing different types of foam sensors.? I have decided that the best one for the X4L electronic drum trigger is the one shown in the picture below.? I’ve been calling it the “tower” coupling.? I believe this to be easier to make than trying to cut a cone shaped coupling.? From what I can tell it works just as good too.

Tech Drawing

Well, we have gotten pretty far into this project, now we just need a foam sensor coupling.? The picture above is the foam sensor coupling we will be making.

$1.00 grips

I bought these hand grips at a local dollar store for $1.00.? Yes, that’s right, $1.00.? Unfortunately, they only colors to choose from was purple, pink, orange, and yellow.? Black would be nice, but at $1.00 yellow will work.

foam grips

Slowly remove the foam from the grips.? This can be done by rolling the foam off, but you will have to turn the foam right side out once it is removed.

1/2? copper pipe

Now that we have the first part of our composite foam sensor coupling, we need to cut the other part.? We will cut the other foam from a foam sanding block.? In order to get the right size we will need to make a custom cutting tool.? Using a piece of 1/2″ copper pipe(about 8-12″ long), sharpen one of the ends of the pipe.? This can be done with a round file and file from the inside of the pipe as shown in the picture.? Please be very careful when doing this. It is very easy to slip and cut yourself.

sanding block #1sanding block #2

Grab a foam sanding block, and with light pressure against the end of the sanding block, start turning the pipe into the foam. You do not have to push very hard to make it cut. Let the pipe do the cutting.? If you try to push the pipe to fast, your foam core will not come out right. Go all the way through as shown in the picture above.? When taking the foam core out, take your time. You do not want to tare the foam.? Slowly pull and twist the foam core out of the pipe.? Using the drawing at the beginning of this post, cut the foam cores to size (1-1/4″ long) using a good sharp razor blade.

grip cut #1grip cut #2grip cut #3

We will need to cut the foam grips down to the size shown in the drawing at the beginning of this post. To help make the cuts good and straight, I cut a hole in a scrap piece of MDF with my hole saw.? I used a 1″ hole saw.? Push the foam grip through the hole so it sticks out only 7/8″ past the edge. Use a good sharp razor blade cut the foam to size.

glue parts #1glue parts #2glue parts #3

Now all we have to do is glue the two pieces together.? Using a good white craft glue.? I used the kind for glue rhinestones to clothes.? I choose this glue because it stays flexible.? Coat the inside of the grip foam with a liberal amount of glue.? Now, pinch the & roll the core foam piece, and push it into the grip foam.? Make sure that the bottoms line up.? This is easily done by assembling them upright on a flat surface.? Let dry for 24-48 hours and the foam sensor coupling is finished.

And this is what it should look like:

finished coupling

In the next post we will mount the coupling to the piezo assembly.

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4 Comments  comments 

4 Responses

  1. Is the outer foam necessary?

  2. Yes!

    You would have no support of the foam coupling if it is just the 1/2″ foam core. Without the outside foam it would look like the Leaning Tower of Pisa.

  3. Larry S.

    Is the thickness of the yellow foam critical?

    Walmart has a pair of handgrips for $2 with black foam grips, but the foam doesn’t look as thick as your yellow foam.

    Is it the outer foam squeezing the inner foam for support, what is important? Or is there another factor?

    Thank you for your help.

  4. I don’t think the thickness is a big deal, however if the opening in the black grip is bigger than a 1/2″ it might be a problem. The reason this would be a problem is because a 1/2″ pipe is used to core foam out of a sanding block. I guess one could core with 3/8″ copper pipe if the grip opening is bigger than a 1/2″. Keep in mind that a lot of this DIY stuff is trial and error. If you by the grips and it doesn’t work, you are only out $2.00. One more thing, the yellow foam isn’t really squeezing the inner foam, it is more of a perfect fit and glued in place. Together it makes the foam sensor the same diameter as the piezo element and this is important.

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