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# Simple demo of of the PCA9685 PWM servo/LED controller library.
# This will move channel 0 from min to max position repeatedly.
# I have modified the example code to work with ESC specifically on RC cars.
# Author: Udayan Kumar (original author: Tony DiCola)
# License: Public Domain
# Be sure to secure the car before testing it.
# I generally put it upside down on a small but thick book.
from __future__ import division
import time
# Import the PCA9685 module.
import Adafruit_PCA9685
# Uncomment to enable debug output.
#import logging
#logging.basicConfig(level=logging.DEBUG)
# Initialise the PCA9685 using the default address (0x40).
#pwm = Adafruit_PCA9685.PCA9685()
# Alternatively specify a different address and/or bus:
pwm = Adafruit_PCA9685.PCA9685(address=0x40, busnum=0)
# Configure min and max servo pulse lengths
servo_min = 250 # Min pulse length out of 4096
servo_max = 350 # Max pulse length out of 4096
pulse_freq = 50
# TODO: Change this value to the channel your motor is connected on ADC.
channel = 0
# Helper function to make setting a servo pulse width simpler.
def set_servo_pulse(channel, pulse):
pulse_length = 1000000 # 1,000,000 us per second
pulse_length //= pulse_freq # 60 Hz
print('{0}us per period'.format(pulse_length))
pulse_length //= 4096 # 12 bits of resolution
print('{0}us per bit'.format(pulse_length))
pulse *= 1000
pulse //= pulse_length
pwm.set_pwm(channel, 0, pulse)
# Set frequency to 60hz, good for servos.
pwm.set_pwm_freq(pulse_freq)
print('Moving servo on channel 0, press Ctrl-C to quit...')
while True:
# Move servo on channel O between extremes.
pwm.set_pwm(channel, 0, servo_min)
time.sleep(1)
pwm.set_pwm(channel, 0, servo_max)
time.sleep(1)