The "free", open source, lib files for Arduino are great unless you have different hardware or want to do something differently. For example, the keypad lib is for a 3 X 3 keypad whereas I have a 4 X 4. To modify this, or any other open source lib file, I'll need a C compiler. Years ago, I had a couple that ran on windows but not anymore. What would be a simple, cheap, compiler that I could use to modify lib files? Thanks, Gary
