Servo Motor Control

Learn how timed pulses represent position. You will wire a servo with a shared ground, generate a 50 Hz PWM signal, convert angles into pulse widths, and avoid common power problems.

Last updated July 15, 2026

Build Time: 40-60 minutes
Estimated Cost: $12-$22
Skill Level: Easy

Raspberry Pi PicoRaspberry Pi PicoPWMServoMotion

Project illustration

A visual reference for this build. Use the parts, wiring, and instruction sections below for exact assembly details.

Recommended for

Middle School
High School
Adult Beginners
Homeschool

Skills

What You'll Learn

Understand pulse width control for hobby servos
Generate PWM with MicroPython
Share ground between control and power circuits
Recognize symptoms of an undersized power source

Preparation

Required Parts

Gather these components before starting the build.

QuantityPartNotes

Qty: 1Raspberry Pi PicoMicroPython installed
Qty: 1SG90 micro servo5 V hobby servo
Qty: 1BreadboardFor power distribution
Qty: 3Jumper wiresSignal
Qty: 1Regulated 5 V supplyRecommended for reliable motion

Wiring

Circuit Diagram

The servo signal wire connects to GP16. Servo power uses regulated 5 V, and the external supply ground must connect to Pico GND.

Circuit overview

Pico servo control circuit. Follow the written connection notes and numbered build steps for exact wiring.

Build

Step-by-Step Instructions

Work through each stage in order and disconnect power before changing the wiring.

1. Connect a common ground

Connect the external 5 V supply ground to both the servo ground and a Pico GND pin. A common reference is required for the control pulse.

2. Wire power and signal

Connect servo power to regulated 5 V and its signal wire to GP16. Check the servo manufacturer’s wire colors before applying power.

3. Upload the sweep program

Run the code with the servo horn unobstructed. It should move through 0, 90, 180, and back to 90 degrees.

4. Calibrate safe limits

If the servo strains near either end, narrow the pulse range in set_angle until motion is smooth and quiet.

Programming

Project Code

Upload servo-sweep.py after completing the circuit.

servo-sweep.pypython

from machine import Pin, PWM
from time import sleep

servo = PWM(Pin(16))
servo.freq(50)

def set_angle(angle):
    pulse_us = 500 + (angle / 180) * 2000
    duty = int(pulse_us * 65535 / 20000)
    servo.duty_u16(duty)

while True:
    for angle in (0, 90, 180, 90):
        set_angle(angle)
        sleep(1)