Hello. I found myself in quite a fix a little while back when I came across the article on how to make cheap drum triggers, and I am badly in need of a drumset.

In the article it stated that to get your sound output (using midi) you must link the drum triggers (which are just piezo, or small microphones inside a drum pad) to a drum module which will take the triggers and produce the sound.

I looked up drum modules, and they are way out of my price range (I can buy the drumset for that price).

I then came across the parallel port, and an idea popped in, what if I could use the parallel port as the drum trigger inputs and then write a program (java) for the pc to play a sound when each of the triggers are triggered and a signal comes in.

I just want to know what you think of this, is it even possible to do? Will there be some kind of latency problem?

Thanks all for reading the rather, unusual post.

well I don't think you can connect a pizeo element to a digital input as it generates current. you would need something like a transistor as a switch. how many pad's are you talking about? It's been a while since I used anything with a parallel port but I don't think it had very many inputs. If it was me I would use some thing like this:

http://www.instructables.com/ex/i/40...E506/?ALLSTEPS

Then it could have more inputs and a cool usb wire. and I'm not sure but you might even be able to find existing software that would alow you to control a software midi synth with your keyboard. you might not have to write anything.

EDIT:
found one midikb:

http://helgo.net/simon/midikb/

It looks like you can set it to use any note with any key. then you'd have a cool usb drumkit that could use any midi synth. Now I might want to build something like this where did you get the article on cheap drum triggers?

Hmmmm, you know, the usb keyboard thing is a really good idea. I wonder if I can get it to work with one of the old PS/2 keyboard I have.

I am only planning to put about 4-5 drums (symbals included) so using serial/parallel port shouldn't be a problem. I wrote a java program which can detect when a input is triggered in the serial port.

Soooo.....if I send each piezo through a rectifier and then use that to activate a transistor as a switch and connect that circuit through the input pin and ground on the serial port, it just might work....right?

I will then try the excellent suggestion of hacking the keyboard. Brillant idea

You may have already come across this, but here's the link I was talking about
http://www.electronicdrums.com/pads/pads2.htm

Thanks for everything.

That sounds like it would work. I did something similar to that once with a parallel port, although not with drums. Prolly cost a few bucks to get some breadboards/wires/transistors/etc from radioshack. Also, get one of those little thingies that you can plug into the parallel or serial port that has pin imputs (I think they're origionally designed for jumpers), it makes it alot easier to wire the parallel/serial port into a breadboard. The hardest part about it is the wires like to jump out... so once you get the layout and figure out how it all works and how you want it wired up, you may want to solder it onto a PC board or something... I was never very good at that. :X

a ps2 keyboard would work but if your computer keyboard is also ps2 you wouldn't be able to use them at the same time (technically you are not supposed to plug or unplug ps2 devices without shutting the computer down.) I think your idea is spot on for only a few pads and should work quite well. as I'm a bassist and not a drummer I have no use for this exact project but I will probably build some kind of usb-keyboard midi device, and I wouldn't have had the idea if not for your post; so thank you.

Thanks very much to all who have posted here.

I will try out both methods and post here my results on each to help others trying to do the same thing.

I've taken apart my ps/2 keyboard and since my main one is usb their both working simultaneously. I've just tried connecting two of the contacts from the chip inside the keyboard, and I can type letters.

I'm now going to attempt to hook that up to the drumset using either a piezo, or some kind of contact/plate system.

Thanks everybody for your help.

Drum triggers using contact plate system successful.

Hello all, I've tested the contact plate method. Which consists of something like this.

A biscuit tin lid (The round kind a little less than a foot in diameter). Two pieces of conductive metal (I got mine from the metal sliding pieces of floppies). Take the floppy piece and cut it down the middle, so you have two sections.

Attach a wire to one section of the floppy metal and the other end of the wire to the usb keyboard pin (that mod is shown in the article above). Now, tape that piece of metal by the wire to the top of the tin lid.

Take the other piece and secure it to the base (whatever is under the tin lid). Attach a wire to that and the other end to the other pin on the keyboard you want.

When you take apart your keyboard you should find little rubber squishy things under the keys which are used to make them spring back up. Take a few of these and put the tin lid on them (metal piece side facing downwards). This should be on top of the other metal piece.

Now obtain a software which plays drum sounds when keys are pressed. I use Pyro's drum set which you can get from here
http://www.hitsquad.com/smm/programs/KeyboardDrums/

Now, tap your plate so that the two metal pieces touch, causing the circuit to be made and the equivalent of pressing a key. Pyro's drumset should now pick this up and play a sound. You can reassign the sound to whatever key you want.

If it doesn't work make sure the metal pieces and indeed contacting when you press the plate. Check all other connections, in particular the ones on the usb keyboard.

This needs great improvement which I'm working on (needs frame, better positioning, etc.) but you've got yourself a basic drum pad.

Enjoy!

Cool I'm glad you got it working. I would personally avoid the tape, but I'm the type who solders just about anything. Re-using the "little rubber squishy things under the keys" is a very good idea; one that I probably wouldn't have had.

Thanks for the reply johnson_steve.

This post is more about the usb keyboard module than the drum triggers themselves.
I found it much easier to just take a piece of paper, and put it on the pins, then using a pen mark the pins on the paper.

Then get your wires and tape them to the paper according to your marking. Just place the paper on top of the chip so that the wires are touching the contacts. Everything should then be in order, no soldering, no gluing, and probably nothing touching each other.

Thanks all.

Hello all.

I've attemped to try out the serial port method.
I can't seem to get the connection to be made properly. I think I'm wiring it wrong.

Does anybody know how to connect a current to the serial port as an input.
The above it what I've been doing. I'm quite sure this is wrong though. I searched all over the internet but could not find any sources on how to input data, only output.

I'm assuming that inside the serial port chip there is a connection between CTS port and Ground, but it isn't behaving that way.

Any help would be appreciated.
Thanks.

You can not use the CTS signal in this fashion. RS-232 logic levels are high = +12 and low = -12. As stated before you can damage parallel and serial ports easily trying to pull to much current.

The cheap method would be to use a relay. Connect an open contact of the relay to RTS and CTS. Connect your circuit to the relay coil and ground. Use a relay that can handle the output voltage of your circuit. Your software can then monitor the state of CTS.

Hello, I just tried what you said and it works, so problem solved.

Just out of curiousity, why won't it work when I connect the + terminal of a 12v power supply to CTS pin and the - of the terminal to the ground pin.

Isn't that how modems etc. communicate with the pc? How do they do it?

Thanks for solving the problem