PNP versus NPN sensors

[Kevin Sevcik]

Originally Posted by Ether

Could a simple (and quite inexpensive) NPN transistor be made to work?

I'm hesitant about that without my Art of Electronics to remind me about transistor fundamentals. I think that's alright, but you should have high values for the resistors. Probably dividing down till the base voltage is less than 3.3V. If I remember correctly, an NPN has a diode from base to collector which would be forward biased if you drive the base with more than 3.3V. Which I think would be bad, or atleast wouldn't work properly.

Originally Posted by adciv

The roborio is not the digital side car. Per specs, the DIO ports can take up to 16v. They were designed with being able to take 12v in mind.

That's fascinating information, where did you find it? The RoboRIO specs that I looked at when formulating my answers stated 5.25V max for the logic high of the DIOs, with no mention of a max voltage. The analog IO is listed as +-16V protection, but there's no reason to assume that carries over to the DIO.