RPi Servo SG90 https://www.youtube.com/watch?v=ddlDgUymbxc

servo_sg90.py

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BOARD)
GPIO.setup(7,GPIO.OUT)

# https://www.youtube.com/watch?v=ddlDgUymbxc
# SG90 angle and pulse width
# 0: 0.5 ms
# neutral: 1.5 ms
# 180: 2.5 ms

p = GPIO.PWM(7,50) # 50 Hz
p.start(7.5)       # neutral ((1.5/20) * 100) %

try:
    while True:
        p.ChangeDutyCycle(2.5)  # 0
        time.sleep(1)
        p.ChangeDutyCycle(7.5)  # 90
        time.sleep(1)
        p.ChangeDutyCycle(12.5) # 180
        time.sleep(1)
        p.ChangeDutyCycle(7.5)  # 90
        time.sleep(1)

except KeyboardInterrupt:
    p.stop()
    GPIO.cleanup()