Interface Servo Motor With Raspberry Pi Pico using MicroPython |

Table of Contents

In this tutorial we are going to control an SG-90 Servo motor with raspberry pi pico board, Servo motors are used in a variety of applications such as RC cars, drones, and robot arms. They are also used in industrial applications such as CNC machines and 3D printers. Servo motors have three wires:

There are many beginners suffering from the basics of the Raspberry Pi Pico Board. So I decided to start a series of articles discussing the basics of Raspberry Pi Pico Projects. Check out our Raspberry Pi Pico Projects Tutorials.

In this tutorial, I’m going to run only one Servo Motor. because the Code is only for one Servo motor. if you want to control multiple Servos motors then you have to change the code. If you understand code you will be able to control multiple servos.

Required Components

Raspberry Pi Pico
Servo motor
Jumper cable

What Is Servo Motor

A servo motor is a rotary actuator that uses feedback to control its angular position. It consists of a motor, a gear train, a control circuit, and a feedback mechanism. The gear train reduces the motor’s speed while increasing its torque. The control circuit monitors the position of the motor shaft and compares it to the desired position. The feedback mechanism adjusts the current to the motor, based on the difference between the two positions.

Schematic Diagram for Servo Motor With Raspberry Pi Pico

The schematic diagram is very easy To control Servo Motor With Raspberry Pi Pico please follow the circuit diagram.

Servo Motor —> Raspberry Pi Pico

PWM Pin —> GP0 Pin
VCC Pin —> 3.3V
GND Pin —> GND Pin

The Servo motor consists of three wires; red, brown, and yellow. Two wires are for VCC and ground and the third one is the data or control pin.

Source Code

To program the Raspberry Pi Pico there is various development Software available (like uPyCraft IDE, Visual Studio Code, Thonny IDE, etc.) I used the Thonny IDE that supports Micropython on the Raspberry Pi Pico.

First setup Thonny IDE for Raspberry Pi Pico:- How to Set Up and Program Raspberry Pi Pico

Open the Thonny IDE once it is successfully installed.
Choose the “for all users” option.
Connect the Raspberry Pi Pico board to your laptop.
To create a new project; go to Files > New.
Connect the Raspberry Pi Pico board to the laptop using a USB cable.
Click on the ‘MicoPython(Raspberry Pi Pico)’ option f
Select the interpreter for raspberry Pi Pico

Copy all the below codes and then save all of the codes on Raspberry Pi Pico Board.

Click on the ‘save’ icon to save the program.
After clicking on the ‘Save’, an option ‘Where to save to? can select any of the ‘Raspberry Pi Pico’ options.
Run the program once it is successfully saved and compiled without any bugs.

myservo.py

from machine import Pin,PWM

class Servo(object):
    def __init__(self, pin: int=15, hz: int=50):
        self._servo = PWM(Pin(pin))
        self._servo.freq(hz)
    
    #duty = 1638 = 0.5ms = 65535/2/(T)(1/50)/2*1000
    def ServoDuty(self, duty): 
        if duty <= 1638:              
            duty = 1638
        if duty >= 8190:
            duty = 8190
        self._servo.duty_u16(duty)
        
    def ServoAngle(self, pos): 
        if pos <= 0:
            pos = 0
        if pos >= 180:
            pos = 180
        pos_buffer = (pos/180) * 6552
        self._servo.duty_u16(int(pos_buffer) + 1638)

    def ServoTime(self, us):
        if us <= 500:
            us = 500
        if us >= 2500:
            us = 2500
        pos_buffer= (us / 1000) * 3276
        self._servo.duty_u16(int(pos_buffer))
        
    def deinit(self):
        self._servo.deinit()

from machine import Pin,PWM

class Servo(object):

def __init__(self, pin: int=15, hz: int=50):

self._servo = PWM(Pin(pin))

self._servo.freq(hz)

#duty = 1638 = 0.5ms = 65535/2/(T)(1/50)/2*1000

def ServoDuty(self, duty):

if duty <= 1638:

duty = 1638

if duty >= 8190:

duty = 8190

self._servo.duty_u16(duty)

def ServoAngle(self, pos):

if pos <= 0:

pos = 0

if pos >= 180:

pos = 180

pos_buffer = (pos/180) * 6552

self._servo.duty_u16(int(pos_buffer) + 1638)

def ServoTime(self, us):

if us <= 500:

us = 500

if us >= 2500:

us = 2500

pos_buffer= (us / 1000) * 3276

self._servo.duty_u16(int(pos_buffer))

def deinit(self):

self._servo.deinit()

main.py

after uploading myservo.py myservo.py it’s time to upload the main code, upload below code and

from myservo import Servo
import time

servo=Servo(15)
servo.ServoAngle(0)
time.sleep_ms(1000)

try:
    while True:       
        for i in range(0, 180, 1):
            servo.ServoAngle(i)
            time.sleep_ms(15)
        for i in range(180, 0, -1):
            servo.ServoAngle(i)
            time.sleep_ms(15)        
except:
    servo.deinit()

from myservo import Servo

import time

servo=Servo(15)

servo.ServoAngle(0)

time.sleep_ms(1000)

try:

while True:

for i in range(0, 180, 1):

servo.ServoAngle(i)

time.sleep_ms(15)

for i in range(180, 0, -1):

servo.ServoAngle(i)

time.sleep_ms(15)

except:

servo.deinit()

Conclusion

When you run the code on the Raspberry Pi pico board, you will see that the servo is rotating from 0 to 180 degrees and 180 to 0 degrees continuously.