Hey. I have just finished making the instructions for the first working version. They are admitedly not very good at the moment, but I will be working on them some through the weekend so that they will hopefully be better before the end of the Halloween 2023 competition.
The sole example on the GitHub is of a 'demonic woman screaming'. I will try to get some more up there quickly included the requested pennywise laugh.
I will also be making a more proper schematic than the fritzing version, so that hopefully more documentation will make it all better.
You can use any audio processor but I used Audacity.
Step one:
Click Audio Set Up -> Select Audio Settings
In audio settings change project sample rate to 8000hz.
Step two:
Export it as an MP3 and force export to mono
3
Use an Audio Encoder made by High-Low Tech to create the Arduino variable
Found towards the bottom of this article http://highlowtech.org/?p=1963. That article is also a great resource for making projects like this so I would recommend reading the whole thing.
Copy the output of that encoder and paste it into the variable sample[] PROGMEM on line 4 of the program.