To start with: choice of software license is purely your decision, and I am not challenging that. However, I would like to point out that CC-BY-SA is explicitly incompatible with the GPL, and therefore with all GPLv3-licensed Arduino libraries (see https://www.gnu.org/licenses/license-list.html#ccby). As a practical matter, it means that no-one can distribute compiled sketches (e.g. flashed onto embedded Arduino devices) which use both this library and any GPLed library. It is probably worth documenting this fact, ,assuming you want to keep the CC-BY-SA license. Dual-licensing this library with a GPL-compatible license would be a solution, but would lose the attribution requirement which may be important to you.