Proposal: Update The Use Of attachInterrupt In README.md

[ptoshkov]

Hello,

Thanks for the great project.

In the README there is an example using attachInterrupt without checking the pin with digitalPinToInterrupt.

Proposal:
Change
attachInterrupt(0, irqHandler, FALLING);
to
attachInterrupt(digitalPinToInterrupt(0), irqHandler, FALLING);

[autowp]

Thinks -1 result must be properly handled with error message

[ptoshkov]

After looking at the implementation of digitalPinToInterrupt I see what you mean. I don't know why they use this function without checking the output in the Arduino examples.