A couple of questions about the Raspberry Pi. How to properly organize all connections?

Question

Raspberry Pi

Good afternoon. I want to use this single-payer to control the "Smart Home" system.
But how to get it right.
For example, there are temperature sensors. As far as I understand, all external devices are controlled via GPIO.
Is there any limitation on the length of the conductor from the sensor to the computer. I want to put the Raspberry Pi itself in the hallway, and place the sensor, one in the room and the second outside the window.
But do not buy one Raspberry Pi for each sensor :)
How to connect all this? The same applies to other sensors of which there are a lot for him. All the examples that I saw on the Internet are shown so that the sensors lie next to the "raspberry" itself.

Answer 1

Of course have. For ordinary conductors, this is usually up to 2 meters - anything further may experience problems with stability, depending on the surrounding electromagnetic background
. Radio Beacon" you need to use something specialized
we.easyelectronics.ru/khomin/modbus-rtu-dlya-chayn...
Sensors must be built on microcontrollers and transmit information using the selected protocol.