servo motor controlling

Question

I found a code script in this website generated by a user called 'Hackaholic' but when run it is not working.

It gives me the chance to enter an angle but the servomotor is not moving.

Someone suggested to write this line of code (dutycycle = ((angle/180.0) + 1.0) * 5.0) but I do not know where to replace it in the code below.

import time

import RPi.GPIO as gpio

gpio.setwarnings(False)

gpio.setmode(gpio.BOARD)

gpio.setup(7,gpio.OUT)

pwm = gpio.PWM(7,100)

pwm.start(2.5)

def change(k):

    pwm.ChangeDutyCycle(k)

    time.sleep(1)

try:

    while True:

        k = float(raw_input("enter angle: "))

        k = (1+(float(k)/180))/20

        change(k)

except KeyboardInterrupt:

    pwm.stop()

    gpio.cleanup()

    exit

Answer 1

A couple of points.

1. Servos mostly respond to 50Hz signals, not the 100Hz you are using. I would change pwm = gpio.PWM(7,100) to pwm = gpio.PWM(7, 50).
2. You are a factor of 100 out in the values sent to the dutycycle function, it expects a percentage in the range 0-100. Try changing change(k) to change(100.0*k).