Diagram for an Opto Isolator to stamp2 as an input?

Archiver

Does anyone have an example of using an Opto isolator
before the stamp2 as an input. The voltage coming in
will be 12 vdc. The prox will be looking at the rear axle on
my StampCar. The Prox is powered by 10 to 30Vdc so
I thought I would use power from drive batteries to power
the Prox. Now the problem is protecting the stamp from
the higher Voltage with the Opto isolator

As always, All responses will be appreciated

TIA
Kim

Archiver

In this case connect your input voltage to thru an appropriate current
limiting resistor to the anode of the opto LED. The cathode goes to the
'Prox' ground. On the other side(assuming NPN transistor output) connect
emitter to STAMP ground, collector to an i/o pin(set for input) with a pull-up
resistor.
When 12V is applied the i/o pin will go low.
>
> Does anyone have an example of using an Opto isolator
> before the stamp2 as an input. The voltage coming in
> will be 12 vdc. The prox will be looking at the rear axle on
> my StampCar. The Prox is powered by 10 to 30Vdc so
> I thought I would use power from drive batteries to power
> the Prox. Now the problem is protecting the stamp from
> the higher Voltage with the Opto isolator
>
> As always, All responses will be appreciated
>
> TIA
> Kim
>