I want to trigger my self made instruments from my pd-patch. The patch itself is quite cpu consuming so I need a simple way of doing this.
Is it possible to address 5V pulses to a midi port? Or do I have to go through the pduino-thing? Or another solution?

I am thankful for any replies.
/daniel

Yes, yes and yes.

It sounds like you are comfortable with electronics to some degree, so I'd suggest getting yourself a teensy microcontroller.
Teensy's are smaller than arduinos, but have the added benefit of a usb controller that can be reconfigured as a native MIDI device.
You will need a level shifter of some kind, as the 3.3v pins on the teensy won't give you the voltage/current you need, I'd recommend a darlington array like ULN2803.