Protection from automotive spikes

[hrc]

I've got a project that I may end up using in a car, so being that the alternator can give some rather nasty spikes, what have others done to protect the microcontroller and associated circuits from damage? Zeners? MOV's? Transorbs? RL circuit? Isolated DC/DC module?

 

[Comcokid]

There have been a few threads dealing with this issue. thread240-100040
thread240-98170

The first issue is what voltage your project uses and how much current does it need?