The Help Center defines a few on-topic subjects:
If you have a questions that addresses a specific Raspberry Pi topic, then this is the right Stack Exchange site for you!
For the most part this includes:
- Raspberry Pi hardware, including GPIO and other related electronics.
- Raspberry Pi peripherals
- Software that runs on the Raspberry Pi
- Operating Systems built for the Raspberry Pi
Suppose I have a question on how to wire a specific component, but that component is not specific to the Raspberry Pi (even though the Pi is being used to control it). Is such a question on-topic?
Example:
How do I connect a PIR motion sensor to the Raspberry Pi?
This isn't an example out of thin air; you can assume that some tutorials have been worked through unsuccessfully.