Arduino - RoboRIO Question

[Alan Anderson]

[Disclaimer: I cannot find a schematic to the Spike internals. What I say here is from many-years-old memory and not guaranteed.]

The Spike inputs are not logic level signals. They actually provide power to an optical isolator. The current is supposed to be limited to 40 ma; I do not know what voltage that ends up corresponding to.

The roboRIO Relay outputs have a 40k resistor to ground, so there is no need for a pulldown on the Arduino inputs.