Finger Drum

[Bluebass]

Display Top.jpg

Mega Zen Top.jpg

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MegaZen guts.jpg

[dmitri]

Wow, you really have to have more than ten fingers!:)

[brice]

very nice work

[RayF]

So, the trigger caps are just pressure seated over the hard foam?

It looks great.

[Bluebass]

Thanks for the accolades. This is the first prototype, I have parts to do another, maybe two, but too little time. It is simpler than a e drum kit, for many reasons regarding gigging and construction. Just use the Mega drum schematics and lose the 1/4" phone/trigger jacks and connect the piezos direct to the analog board. Carve out a hunk of wood, drill holes for the trigger wires and display module. Also I felt it most important to have a sturdy jack plate for the MIDI IN/OUT and line/phones on the unit. The caps are pressure fit while the hot glue is hot. It's very important to use the threads on the inside of the recycled caps when attaching to the foam. While glue is warm and you screw on the cap, the cap forms new threads that bind the cap to the foam. So if the glue bond breaks, there will still be a mechanical bond to the foam/piezo/glue cap sandwich. Voila, Mega Zen!

[RayF]

Where did you get such small piezos to fit inside the bottle caps. Did you use typical bottle caps, or are they a larger variety from mega size bottles? They look like typical caps off 20 oz. bottles.

Also how do you keep the piezo wires from twisting while you screw the caps onto the foam? I am guessing you send the wire down through the foam, down through the hole in your wood first, obviously. You must be using really tiny piezos if you aren't dramatically bending the piezo wire to keep it out of the way.

This is a tremendous idea, though.

Just curious. If you got 'carried away' and really applied some force while doing rolls or whatever, will any of the triggers misfire from crosstalk vibration?

[Bluebass]

Hey Ray,
The piezos are little microphones found at allelectronics.com Cat# PE-49. They have a ring of adhesive that holds them in place temporarily while you stick them to the foam, before placing on the cap.
The caps are from 20 oz bottles. I used these only because I had many of them already, but you can use any size. My next unit will use 45 mm diameter ones from the 64 oz Gatorade/or Vitamin Water bottles. I made sure that the outsides of the caps knurl (grip) were consistent. Many of the Coke/Pepsi etc. bottle caps have thin walls and the wall sides bulge a bit. Rather I went with a "house brand" soda bottle cap that had a nice even knurl and side walls - that soda was good too.
I punched out a .75" diameter core of foam, and sliced it top to bottom for only HALF of its diameter. This slice is the wire chase for the piezos. I felt it necessary to counter bore into the wood about 1/3 to 1/2 the height of the cap so that the cap cannot be mistakenly peeled/ripped off of its foam support. Make sure you do this or your unit will not be too road worthy.
My unit is worn like a guitar, and gets beat up quite a bit. I have not had it misfire once. I can however cause numerous triggers to fire, if I hit the wood very hard with my knuckles, but that's not anywhere near normal operation. My Roland Stage Custom set has MORE crosstalk than this unit.

[RayF]

This is very cool. I just did a google on plastic caps and found all kinds of sizes to buy.

I always thought you had to affix your piezo to the underside of your striking surface, in this case the plastic cap. So, in your case the hot side of the piezo is not glued to the cap, it just touches it as you screw the cap down on the foam?

[RayF]

RayF wrote:
Greetings Dmitri,

I've been getting useful information off the discussion board but wanted to just cut to the chase.

I am looking to make a finger drum, ala zendrum. I made one, as I mentioned on the board, and have gotten good info on making another one.

I want to make mine with at least 48 - 72 triggers. I cannot see myself constructing a midi board and would need to buy one fully made and ready to install. What would you suggest? Can a large one be made?

It can be extended to up to 64 inputs, but not right now(if ever) and only using Atmega644.

Quote:
If I purchased more than one megadrum (say three), can they be linked together? Would I be able to utilize three midi outs for the total number of triggers per 3 units, or would I only be able to use each midi out for each mega drum installed? I'd like to be able to send the full trigger signal to one module, rather than three signals to three modules.

MegaDrum units can be chained, see this discussion. You can chain more than two MegaDrum units and than use just one MIDI I/O port (or MIDI over USB) to have MIDI signals from all units in one cable/port.


Quote:
Thanks for any help and advise,
Ray

You're welcome. To let others see answers it is better to ask these questions in the forum.

[elrules]

I want to make mine with at least 48 - 72 triggers. I cannot see myself constructing a midi board and would need to buy one fully made and ready to install. What would you suggest? Can a large one be made?

48 triggers?? velocity sensitive? only with two megadrums, and for the money that cost, you can buy a 49 keys MIDI keyboard with sliders and wheels!! The triggers are closer to each other but they can be also used to play the piano