problem motion detection + midi

I noticed that after a few different uploads the device will start to act oddly ( aka bits of older code will still be there but merged with the new ones?)

That'd odd - I guess maybe you had managed to save to flash so it runs all the time - but that's a bit dangerous so it's buried in the settings, or maybe you wrote to .boot0 or similar - this might help: https://www.espruino.com/Saving

Writing to certain files means that you can have code that runs all the time, even after a reset.

However require("Storage").eraseAll();reset() will clear everything out and refresh the device making it completely clean, whatever came before :)