I am looking to handle more pins from Pure Data and could not find a way to do so.
I have tried myself and made quite some google-ing and still couldn't have a solution.

Attached is my edited sketch. The changes I made are in the "pd sending digital outs" --> "pd generate digital outs messages". I have changed the message "digital 1 $1" to "digital 24 $1" (accidentally burned my #1 pin). However, I only could send a HIGH signal to pin #24 when I activate the trigger box. When I de-activate the trigger box, it does not send a LOW signal (tested this with a LED). The weird thing, to me, is that when I trigger the pulse inputs for all, it can be switched on and off accordingly. In an occasion, I got it work but since then I couldn't duplicate it. I find this extremely weird. (I have tried it many many times and a lot of different cases occurred, even tried switching my USB ports)

Would you be able to point out my mistakes and let me know what should I do to get it right? Any advice will be very much appreciated.

p/s: Pardon for my English. I am not native English speaker.

http://www.pdpatchrepo.info/hurleur/arduinomega-test-experimental.pd

@umduh said:

I've had similar trouble getting pins 24 to 33 to work with pduino on the arduino mega. I have found, however, that pins 34 to 53 can be activated. You just need to add in some more [inlet] and [digital 34 $1( etc, in the same window where you edited pin one to be pin 24. Doing so automatically creates new inlets on the [pd generate digital out messages] object.
I've uploaded a rough example that includes pins 34 and 53. I hope that helps.

Hi umduh, thanks for sharing. So 24-33 is bound not to work? I recalled when I tried higher pins and yield mix results as well. Maybe I didn't document it well and didn't find out the pattern. Anyway, I managed to make do with limited pins from 0 to 23 (burned another 4 out before the final presentation), still barely okay for 20 pins to work. LOL!