Raspberry Pi LESSON 28. Controlling a Servo with Raspberry Pi and Python

In this lesson we present a simple step-by-step tutorial on controlling a servo with the Raspberry Pi. The lesson shows how to accurately achieve any desired position.

Full lesson details at:

[mbv]

6 years later and this is still a great tutorial. Thank you Paul

[martinlewis]

I'm jumping back and forth between the newer Python tutorials and these. Lots of fun. Thanks again!

[Lecon]

Today I decided that I would get into Raspberry Pi and I thought i'd do a search and came upon this lesson. I used to have fun with turbo languages and was pretty upset when MSDOS went away. I haven't done any code since 99. This may be the beginning of a new hobby for me. Thank you.

[albireo]

Paul: Thank you for the great video!
Guys: I added Python code to display DutyCycle values onscreen and to make a clean departure on Ctrl-X. The code below is calibrated for my particular servo.

# Python code for Raspberry Pi: Rotate servo horn from 0 to 180 degrees; 180 to 0 degrees forever (Ctrl-X to stop)
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM) # That is BCM pin number
servoPin=18
GPIO.setup(servoPin, GPIO.OUT)
pwm=GPIO.PWM(servoPin, 50) # BCM pin 18 at 50Hz frequency
pwm.start(2) # DutyCycle 2 is "full-left" position (0 degrees, if you will) on my servo

try:
while(1):
for i in range(0, 180):
DC=1./18.*(i)+2
pwm.ChangeDutyCycle(DC)
print("A:DutyCycle: %s" % DC) # Display DC values onscreen
time.sleep(.01)
for i in range(180, 0, -1):
DC=1/18.*i+2
pwm.ChangeDutyCycle(DC)
print('\033[1;36mB:DutyCycle: %s\033[1;m' % DC) # Display cyan-colored DC values onscreen
time.sleep(.01)
except KeyboardInterrupt: # Clean departure on Ctrl-X
pwm.stop() # Stop the servo
GPIO.cleanup() # Housekeeping :)

[berndklee]

Thank you so so much for your videos! There are so many others, but either they're only 2 minutes long (which is clearly not enough to explain such a complex thing), or they take about an hour, but do not manage to explain it anyway! And this is why I normally don't watch those videos from the beginning to the end, but YOUR Videos are simply worth the time! I owe you a lot, thank you 👍 Greetings from Germany! 👋

[johncgibson]

Your PWM library is very good and stable. I have seen other people's programming that the servo arm is always twitching. Your servo control is very precise and no twitching at all.

[resrussia]

Thanks for an excellent video on controlling servo motors. As a result of your video, my comfort working with the RPi and servo motors has increased tremendously. Keep up the good work.

[adamc]

This lesson helps me understand how to start coding small things its awesome. You knowledge helps a lot . Big Up

[Tyrad]

thank you for these tutorials. still incredibly helpful and relevant 4+ years later

[MartinJohnstone]

Awesome clarification of PWM! Man, I've been looking for a lesson like this! Very clear and concise, I checked out lesson 27 - great clarification! Thank you!

[rajcodes]

Thanks Sir Paul - you have surely add to my insight how to control electronics using software - really appreciated.Your pace allows beginners to understand better and you explain stuff nicely.Thanks so much again - I have a pi but I guess i need to get a servo and a external power supply to try this out.

[shampavmancg]

This was very informative. Thanks.
I've started a project to build my own gimbal for which the PWM explanation and this video will be very helpful..


Thanks

[prathamva]

Thank you for the Amazing tutorial.I wish i had Mathematics Professor like you.The Math logic you used in the program made me to Realize the importance of" Lines and Angles" :)

[jatinmayekar]

Thanks a lot sir!!Wish we had teachers like you

[mikehauk]

I will admit... frustration doesnt come close to how I was feeling...
I sat back and told myself, "your overthinking everything. Let the pi do the work..."
WORKS like a charm!

[erygion]

Wonderful lesson Mr. Mcwhorter, (I love the long ones) all the possibilities with the other lessons makes quite the tool set. Thank you sir. ❤🍇🥧

[aynursunagatullin]

I really liked your explanation especially the formulae, theory and code

[jingyiwu]

Superior!!! All the control that you can imagine for control a servo!!!!

[anarchylabs]

Just to keep a good video going. the 9g servo stats are: full left = 2. mid = 7. full right =12

[Fiskers]

When you calculate "DC" and multiply 1./18. to make it (float) the variable must also be a float, input must be a float also. float(input("text") this is so you multiply Float times Float. See what I mean... Saw this error while running "Thonny Pi IDE" Loved the lesson. John