IO Sensors

I'm trying to learn more about the IO ports on the Hub. I see they are there and I assume that I could hook stuff up to them to detect something, but I don't know what. I've also not been able to track down any documentation.



Could someone help point me to documentation on this? I saw someone say look at the wiki, but I haven't found where on the wiki this is addressed so a specific page would be helpful.



Thank you!

Devices that can be used for detecting/sensing anything as inputs can only be digital. Same applies for the outputs to which you can connect your devices as triggers