import servo
import machine

SERVO_PIN = 23
POT_PIN = 34

def main():
    pot = machine.ADC(machine.Pin(POT_PIN))
    s = servo.Servo(machine.Pin(SERVO_PIN))
    print("running...")
    while True:
        speed = pot.read()
        # create 'dead zone' at bottom of throw
        if speed < 100:
            speed = 0
        s.write(speed/4096 * 180)
        machine.idle()

if __name__ == "__main__":
    main()

main.py

diagram.json

import machine
import math

class Servo:
    def __init__(self,pin_id,min_us=544.0,max_us=2400.0,min_deg=0.0,max_deg=180.0,freq=50):
        self.pwm = machine.PWM(machine.Pin(pin_id))
        self.pwm.freq(freq)
        self.current_us = 0.0
        self._slope = (min_us-max_us)/(math.radians(min_deg)-math.radians(max_deg))
        self._offset = min_us
        
    def write(self,deg):
        self.write_rad(math.radians(deg))

    def read(self):
        return math.degrees(self.read_rad())
        
    def write_rad(self,rad):
        self.write_us(rad*self._slope+self._offset)
    
    def read_rad(self):
        return (self.current_us-self._offset)/self._slope
        
    def write_us(self,us):
        self.current_us=us
        self.pwm.duty_ns(int(self.current_us*1000.0))
    
    def read_us(self):
        return self.current_us

    def off(self):
        self.pwm.duty_ns(0)
