Arduino - Potentiometer Triggers Servo Motor
In a previous tutorial, We have learned how to rotate servo motor according to the potentiometer's output value. In this tutorial, We are going to learn how to:
- If the potentiometer's analog value is greater than a threshold, rotate servo motor to 90 degree
- If the potentiometer's analog value is lower than a threshold, rotate servo motor back to 0 degree.
- If the potentiometer's output voltage is greater than a threshold, rotate servo motor to 90 degree
- If the potentiometer's output voltage is lower than a threshold, rotate servo motor back to 0 degree.
Hardware Required
1 | × | Arduino UNO or Genuino UNO | |
1 | × | USB 2.0 cable type A/B | |
1 | × | Potentiometer | |
1 | × | Servo Motor | |
1 | × | Jumper Wires | |
1 | × | (Optional) 9V Power Adapter for Arduino | |
1 | × | (Optional) Screw Terminal Block Shield for Arduino |
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About Servo Motor and Potentiometer
If you do not know about servo motor and potentiometer (pinout, how it works, how to program ...), learn about them in the following tutorials:
Wiring Diagram

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Arduino Code - Analog Threshold
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-potentiometer-triggers-servo-motor
*/
#include <Servo.h>
// constants won't change
const int POTENTIOMETER_PIN = A0; // Arduino pin connected to Potentiometer pin
const int SERVO_PIN = 9; // Arduino pin connected to Servo Motor's pin
const int ANALOG_THRESHOLD = 500;
Servo servo; // create servo object to control a servo
void setup() {
servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object
servo.write(0);
}
void loop() {
int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin
if(analogValue > ANALOG_THRESHOLD)
servo.write(90); // rotate servo motor to 90 degree
else
servo.write(0); // rotate servo motor to 0 degree
}
Quick Steps
- Connect Arduino to PC via USB cable
- Open Arduino IDE, select the right board and port
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to Arduino
- Rotate the potentiometer
- See the change of servo motor
Arduino Code - Voltage Threshold
Potentiometer's analog value is converted to voltage value, and then compared to voltage threshold to triggers servo motor
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-potentiometer-triggers-servo-motor
*/
#include <Servo.h>
// constants won't change
const int POTENTIOMETER_PIN = A0; // Arduino pin connected to Potentiometer pin
const int SERVO_PIN = 9; // Arduino pin connected to Servo Motor's pin
const float VOLTAGE_THRESHOLD = 2.5; // Voltages
Servo servo; // create servo object to control a servo
void setup() {
servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object
servo.write(0);
}
void loop() {
int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin
float voltage = floatMap(analogValue, 0, 1023, 0, 5); // Rescale to potentiometer's voltage
if(voltage > VOLTAGE_THRESHOLD)
servo.write(90); // rotate servo motor to 90 degree
else
servo.write(0); // rotate servo motor to 0 degree
}
float floatMap(float x, float in_min, float in_max, float out_min, float out_max) {
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
Video Tutorial
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Potentiometer and Servo Motor on Commercial Products
Function References
The Best Arduino Starter Kit
See Also
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