Suggestion: Progressive Pin definition from int, const int to MACRO.

[agy-why]

Dear SparkFun,

In the tutorial DistanceSensor the pin are defined for the first time as const int, instead of int. I think it is a great opportunity to introduce constants.

However I found that such values like pin ID may not need a variable and I believe can be solved via a MACRO definition since the latter do not require memory space.

As a results I could imagine introducing const int in the second project and #define XXX_PIN YY in the third project. The advantage being a smooth learning curve and introducing the challenges of memory management in embedded systems.

Thank you for your work, and your contributions to the open hardware community,

I wish you a nice day,

Yori