Newbie, I'm afraid, though I'm not doing badly so far.
I've built a digital speedo with an arduino and some LED displays. It picks up pulses from a hall-effect device I've stuck by the drive train of my truck. Currently, the output of the device (which handily bounces between 0 and 5v) is connected straight to an input pin on the arduino, but I'm concerned that because the wire runs near the high-voltage ignition cables for the engine, it may pick up some spikey noisy stuff - is there a basic way I can protect my arduino from trouble?
Many thanks
h