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For my proyect, I need to conect my NodeMCU to a servo motor as well as a push button, the thing is, the distance from the NodeMCU and both components has to have a distance of around 6.10 meters (or 20.0131 feet), I dont know if it is possible to do this connection, I worry if the pwm signal or the voltage would drop by the time it reached either component. I havent been able to try this because I dont have long enough cables to do the connections. In the case that it would be possible, what type of cable should I use and should I add something extra to the circuit to make it work better? Thanks.

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  • use the long wire for the pushbutton part of the circuit ... use it to activate the LED of an opto-isolator .... basically, pressing the button lights an LED at the arduino ... you can use a battery to run the opto-isolator or use power from the arduino ... adjust the LED series resistor to obtain a good signal
    – jsotola
    Nov 12 '20 at 19:09
  • you could use additional nodeMCUs, they are cheap and wireless.
    – dandavis
    Nov 13 '20 at 23:50
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A push button won't be a problem. That is a very simple change in resistance from open circuit to a few ohms. You just need a low enough resistance to force the voltage coming through weak internal pullup resistor down to ground. It looks like 22 gauge wire has about 52.7 ohms / 1000 meters.

I don't think 6 meters of 22 gauge wire will be a problem for a 5V PWM signal either. If it's a very electrically noisy environment you might want to use shielded or twisted pair cable, but it seems unlikely that would be needed.

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I would suggest a pull up resistor forcing at least 1 mA or more of current through the switch contact. This helps keep the switch contact clean if it is not rated for dry switching. Then from the junction of the pull up resistor put a 20 - 100K resistor in series with your input pin. You can also add a 100nF cap between the input and ground to kill noise. This forms a low pass filter and denounces some of the switch noise. The other wire to the switch will be ground. I did this a lot with 12/24VDC control systems. If you do several inputs check your currents and be sure you do not over power the Arduino. This will forward bias the top input protection diode pushing current into the Arduino VCC. The inputs are typically rated at 20mA but check to be sure yours is rated properly.

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