i have a question regarding cable length for a pushbutton in a home automation project.

I would like to have some light switches (regular switches from home shops) connected to my arduino - so 5v - and have that signal back to my arduino next to the electrical core of the house. My question is how long can i go with a good quality shielded cable with the 5v output from Arduino (or another source) to the switch (and back to my arduino.

Thank you for your answers.



  • \$\begingroup\$ What length are you trying to achieve? 10m, 50m? \$\endgroup\$ – Wesley Lee Apr 3 '16 at 16:14
  • \$\begingroup\$ i'd say something like 20-25m max from the arduino to the switch (and back of course) \$\endgroup\$ – Tim Apr 3 '16 at 18:34

Well, if the shielded cable is 22AWG, the resistance/meter is about 0.053 ohms. Multiplied by thirty is 1.59 ohms. Assuming the HUGE input draw of the I/O pin of 1mA, the voltage drop accross the circuit would be 1.59R x 0.001A. This would be a drop of 0.00159V. You should be fine running the cable for 30 meters and beyond :)


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