Hi
Does anyone have a circuit or must-do's for an opto-isolator circuit for an Arduino. I want to connect three long wires, from weather instruments, to my Arduino. We have a lot of lightning storms in our area so I must protect the Arduino and GSM module from EMF Spikes.
Any ideas, circuits, suggestions?
Best regards
Andre
Use an appropriate Transorb or a Varistor from each conductor to earth ground.
EDIT: Do some research on "surge withstand capability" "SWC"
A small opto isolator isn't going to save you from lightning. It should protect from all the
pickup induced on the wires, but provide a good earthing stake outside the building directly
bonded to the wire.
Lightning jumps many feet at a time (stepped leader), you have to provide a solid
alternate route to ground for the current and perhaps a metre or more of isolation to
have a chance against a direct hit to the cabling:
Using a length of optical fibre / lightpipe to isolate, bright LED at one end, good photo
transistor at the other (you can get black plastic coated light pipe to keep ambient light out) - its like an opto-isolator but can be several metres long.
I suspect someone has already investigated such a lightning-proof opto-isolation set-up
before, google around maybe?
Do your three long wires carry analog or digital signals ?
