Distance between Arduino and sensors

Hallo to everyone.
I'm sorry if my question is too stupid but I'm just starting, so...

I want to play with Arduino sensors and I want to put some sensors (illumination, temperature and moisture) in my home and garden, my question is how long can be the cables?
There is a formula to calculate how much the signal will degrade?

Very grateful for every help!


There is a formula to calculate how much the signal will degrade?


is how long can be the cables?

It depends entirely on the sensor.
Look at sensor that uses the 1 wire bus, that is good for that sort of thing.

I am not an expert so treat that with care:

If you are using a resistivity sensor like temperature you can use a 4 wire-connection (at least in german we call it so). Two wires are connected to a constant current source and with the other two wires you do measure the current drop across the sensor. Use an op-amp circuit with very high input impedance (e.g INA114). So the length should not matter (the current along the sensor is constant).

The longer the cables the more noise you might get from external radiation. So you might want to use shielded cables. Or/and use a filter (low pass).

Another Option is to either use an external AD-converter close to the Sensor or an IC which converts in in discrete time signals (forgot the name of it) which as de facto also an AD-conversion

And do not be desperate if Grumpy_Mike does not give you much information. Sometimes less is better.

Thank's guys!