I love to play with existing Gadgeteer modules and build prototypes for all sorts of projects in short time - by just plugging them in.
But in reality, most of the sensors I have come across for sensing the real world has been withOUT the beloved Gadgeteer plug - which then kind of stops the project.
I know that many of you fantastic guys in this community are just hooking up a few wires, a pull-up resistor and a few custom interrupt event handlers, and then you are moving on.
I am not really a hardware guy, and I think it would be really fantastic with some best practices or quick advice for the ones that wants to try out some sensors that has simple digital I/O of some kind.
Types of input you could start to cover is PNP, NPN, relay which should be really easy to do. But not for me!
I agree the info at this site is somewhat short of the electronics of things for interfacing gadgets to the gadgeteer. I believe it’s expected the end user already has the basic knowledge of electronics interfacing to then work with firmware interfacing that is supported here more. I find though also it doesn’t hurt to ask any question here because all it takes is someone to at least point in the right direction to the answer of your question. Google is your best friend also when it comes to figuring things out for anything.
To answer your request:
NPN and PNP are transistor types. Do a google search for “how to use a transistor”
For a relay interface, going to this link should get you going: Basic Transistor Circuits
Google "ttl(transistor transistor logic) relay interface circuit for more results
It’s really important to ge the basics in electronics as that will help you enormously.
I use this book Make: Electronics, 3rd Edition - Print which has been great. I still refer back to it all the time…