You can use multiple files. All the other .h, .ino and .cpp files in the same folder will show up in tabs in the IDE. The little arrow at the right end of the tab bar will let you create a new tab.
You can use multiple files. All the other .h, .ino and .cpp files in the same folder will show up in tabs in the IDE. The little arrow at the right end of the tab bar will let you create a new tab.