Hi, I'm a singer/guitarist who has an idea which I need help to put into practice! I'd like to have a unit operated by (perhaps) 4 foot-switches that produce 4 different drum / cymbal sounds. The problem is that I can't find an appropriate set-up; I don't want a unit that can be programmed to produce riffs, just simply one that will sound a high-hat when pedal 1 is depressed, a crash-cymbal on number 2 etc. Can someone wiser than me please help?! Thanks, in anticipation, Dave.
Normally, that would be done with [u]MIDI[/u]. MIDI is a computer-music interface and file standard. For example, you can play a MIDI keyboard/instrument, capture the MIDI information (notes, timing, and "loudness") into a computer, and then you can play virtual instruments. Most background music you hear in movies is now MIDI instead of a real orchestra.
You can also connect a MIDI instrument to a computer (or another MIDI instrument/synthesizer) to play virtual instruments in real-time. Sometimes you can get latency (delay) when playing in real-time through the computer, so that might not be the best way to do it, but some people get the latency down to acceptable levels.
You can also send the MIDI data out to a MIDI instrument (typically a keyboard) and the computer can play the instrument.
The original MIDI spec required a special connection, but now you can use USB.
[[u]Electronic drums[/u]](http://en.wikipedia.org/wiki/MIDI\) include both a MIDI controller with a MIDI output, and a drum synthesizer with an audio output for connection to an amplifier (or headphones, etc.).
You could build MIDI drum controller with the Arduino, but I'm not sure if the Arduino is the best thing for making a MIDI synthesizer/instrument that makes the actual sound. It could be done (with an added audio shield), but I just have no clue if it's the best way to do it.
I'd like to have a unit operated by (perhaps) 4 foot-switches...
It would be better to use some sort of sensor that can sense how hard you hit the pedal (Piezo transducers are often used with drums). In MIDI this is called "velocity" and it's related to how hard you hit the drum, cymbal, keyboard, etc.
Your soundcard has a synthesizer built-in so you can download and play MIDI files. But, if you want to make an actual MIDI instrument or if you want to change the virtual instruments or record & edit MIDI files, you'll need special software for that.