How to power Arduino with VIN?

Here’s the short, safe guide to powering an Arduino via VIN. 1) What VIN is (and isn’t) VIN feeds the board’s 5 V linear regulator. Use it when your source is \> 6 V and < ~20 V. Recommended: 7–12 V (sweet spot: 7–9 V to reduce heat). Do NOT put 5...