Protecting Motes .... or not bother?

[gregcope]

Hi,

So I have fried one of my MoteinoMegas as I accidentally sent 14V down a pin on vehicle powered project when an enable pin is next to a vehicle VCC pin (14V).  Trying to debug an issue I touched both pins with a multimeter probe.

Is it worth isolating pins (optocoupler?) to protect or is this just a stupid one off?

Or maybe another question is when to isolate?

Thanks.

[LukaQ]

Depending on environment used, you might go for optocoupler, resistor + diode to VDD, resistor + zener to GND... just to name a few. You have some options. Optos would be where your moteino ground is not the same as "on the other side" or you could expect large differences between what you measure and you input pin. You could do mix options from above for different pins.