Arduino Sensor Shield V5 0 Manual -

In some nights, when the workshop lights dimmed and the moon was a thin coin in the sky, Jonah swore he could hear a soft, almost inaudible hum — as if the shield were humming a tune of its own. Perhaps it was only the fan, or the distant rush of rain. Or perhaps, in the way that tools sometimes keep the echo of every hand that worked them, it remembered the voices it had answered and kept a tiny, faithful tune: ready, connected, alive.