My project is to build a raspberry based emergency button for use at home (if someone feels unwell, for example).
I would like to use the raspberry pi as a receiver of a signal sent by a (short-range?) radio transmitter (on a press of the button) for further processing. I imagine it would be similar to how car remote key entry systems work.
I have a hard time figuring out what hardware to use as the sender and the receiver. Many articles I found are about FM radio but I think that is not what I need, or is it?
Hope someone can give me a step-by-guide on how to go about this, hopefully including some information what hardware exactly I need.
Thanks very much!