Be careful with digital 13. It gets strobed by the bootloader. The resistor will keep you from driving large loads, but you can use it as an input or a logic level output. You just won't get more than a few milliamps through it.
Be careful with digital 13. It gets strobed by the bootloader. The resistor will keep you from driving large loads, but you can use it as an input or a logic level output. You just won't get more than a few milliamps through it.