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/*
Controlling a servo position using a potentiometer (variable resistor)
by Michal Rinott <http://people.interaction-ivrea.it/m.rinott>
modified on 8 Nov 2013
by Scott Fitzgerald
modified for the ESP32 on March 2017
by John Bennett
see http://www.arduino.cc/en/Tutorial/Knob for a description of the original code
* Different servos require different pulse widths to vary servo angle, but the range is
* an approximately 500-2500 microsecond pulse every 20ms (50Hz). In general, hobbyist servos
* sweep 180 degrees, so the lowest number in the published range for a particular servo
* represents an angle of 0 degrees, the middle of the range represents 90 degrees, and the top
* of the range represents 180 degrees. So for example, if the range is 1000us to 2000us,
* 1000us would equal an angle of 0, 1500us would equal 90 degrees, and 2000us would equal 1800
* degrees.
*
* Circuit: (using an ESP32 Thing from Sparkfun)
* Servo motors have three wires: power, ground, and signal. The power wire is typically red,
* the ground wire is typically black or brown, and the signal wire is typically yellow,
* orange or white. Since the ESP32 can supply limited current at only 3.3V, and servos draw
* considerable power, we will connect servo power to the VBat pin of the ESP32 (located
* near the USB connector). THIS IS ONLY APPROPRIATE FOR SMALL SERVOS.
*
* We could also connect servo power to a separate external
* power source (as long as we connect all of the grounds (ESP32, servo, and external power).
* In this example, we just connect ESP32 ground to servo ground. The servo signal pins
* connect to any available GPIO pins on the ESP32 (in this example, we use pin 18.
*
* In this example, we assume a Tower Pro SG90 small servo connected to VBat.
* The published min and max for this servo are 500 and 2400, respectively.
* These values actually drive the servos a little past 0 and 180, so
* if you are particular, adjust the min and max values to match your needs.
*/
// Include the ESP32 Arduino Servo Library instead of the original Arduino Servo Library
#include <ESP32Servo.h>
Servo myservo; // create servo object to control a servo
// Possible PWM GPIO pins on the ESP32: 0(used by on-board button),2,4,5(used by on-board LED),12-19,21-23,25-27,32-33
// Possible PWM GPIO pins on the ESP32-S2: 0(used by on-board button),1-17,18(used by on-board LED),19-21,26,33-42
// Possible PWM GPIO pins on the ESP32-S3: 0(used by on-board button),1-21,35-45,47,48(used by on-board LED)
// Possible PWM GPIO pins on the ESP32-C3: 0(used by on-board button),1-7,8(used by on-board LED),9-10,18-21
int servoPin = 18; // GPIO pin used to connect the servo control (digital out)
// Possible ADC pins on the ESP32: 0,2,4,12-15,32-39; 34-39 are recommended for analog input
// Possible ADC pins on the ESP32-S2: 1-20 are recommended for analog input
#if defined(CONFIG_IDF_TARGET_ESP32S2) || defined(CONFIG_IDF_TARGET_ESP32S3)
int potPin = 10; // GPIO pin used to connect the potentiometer (analog in)
#elif defined(CONFIG_IDF_TARGET_ESP32C3)
int potPin = 4; // GPIO pin used to connect the potentiometer (analog in)
#else
int potPin = 34; // GPIO pin used to connect the potentiometer (analog in)
#endif
int ADC_Max = 4096; // This is the default ADC max value on the ESP32 (12 bit ADC width);
// this width can be set (in low-level oode) from 9-12 bits, for a
// a range of max values of 512-4096
int val; // variable to read the value from the analog pin
void setup()
{
// Allow allocation of all timers
ESP32PWM::allocateTimer(0);
ESP32PWM::allocateTimer(1);
ESP32PWM::allocateTimer(2);
ESP32PWM::allocateTimer(3);
myservo.setPeriodHertz(50);// Standard 50hz servo
myservo.attach(servoPin, 500, 2400); // attaches the servo on pin 18 to the servo object
// using SG90 servo min/max of 500us and 2400us
// for MG995 large servo, use 1000us and 2000us,
// which are the defaults, so this line could be
// "myservo.attach(servoPin);"
}
void loop() {
val = analogRead(potPin); // read the value of the potentiometer (value between 0 and 1023)
val = map(val, 0, ADC_Max, 0, 180); // scale it to use it with the servo (value between 0 and 180)
myservo.write(val); // set the servo position according to the scaled value
delay(200); // wait for the servo to get there
}
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