This tutorial shows you how to wire and program a servo motor with Raspberry Pi Pico using PWM (Pulse Width Modulation) in the Wokwi simulator. Perfect for robotics, automation, and mechanical control projects!
What is a Servo Motor?
A servo motor is a rotary actuator that allows precise control of angular position (usually 0° to 180°). Unlike regular DC motors, servos can move to and hold a specific angle, making them ideal for robotic arms, steering mechanisms, camera gimbals, and more.
Types of Servo Motors
Standard Servo (180° rotation):
- Rotates from 0° to 180°
- Most common type
- Used in this tutorial
Continuous Rotation Servo:
- Rotates continuously like a DC motor
- Speed and direction controlled by PWM
360° Digital Servo:
- Full 360° positioning
- Higher precision and torque
Getting Started with Wokwi
Step 1: Open Wokwi and Create New Project
- Go to https://wokwi.com
- Click "New Project"
- Select "Raspberry Pi Pico" or "Raspberry Pi Pico W" as your board
Step 2: Add Servo Motor Component
Add Servo:
- Click the blue "+" button
- Search for "servo" or "servo motor"
- Select "Servo Motor"
- Click to add it to your workspace
- The default is typically a standard 180° servo
Step 3: Understanding Servo Motor Pins
A standard servo has 3 wires:
| Wire Color | Function | Connection |
|---|---|---|
| Brown/Black | Ground (GND) | Connect to GND on Pico |
| Red | Power (VCC) | Connect to VBUS (5V) on Pico |
| Orange/Yellow/White | Signal (PWM) | Connect to GPIO pin on Pico |
Note: Wire colors may vary by manufacturer:
- Signal: Orange, Yellow, or White
- Power: Red
- Ground: Brown or Black
Step 4: Wire the Circuit in Wokwi
{
"version": 1,
"author": "Gabriel Barrionuevo",
"editor": "wokwi",
"parts": [
{
"type": "board-pi-pico-w",
"id": "pico",
"top": -22.45,
"left": -102.05,
"attrs": { "env": "micropython-20241129-v1.24.1" }
},
{ "type": "wokwi-servo", "id": "servo1", "top": -30.8, "left": 48, "attrs": {} }
],
"connections": [
[ "servo1:GND", "pico:GND.8", "black", [ "h0" ] ],
[ "pico:3V3", "servo1:V+", "green", [ "h0" ] ],
[ "pico:GP15", "servo1:PWM", "green", [ "h0" ] ]
],
"dependencies": {}
}
Based on your diagram, make these connections:
Servo Motor Connections:
- Brown/Black wire (GND) → GND on Raspberry Pi Pico
- Red wire (VCC) → VBUS (5V) on Raspberry Pi Pico
- Orange/Yellow wire (Signal) → GP15 on Raspberry Pi Pico
Wiring Steps:
- Click the GND (brown/black) pin on servo → drag to GND on Pico
- Click the VCC (red) pin on servo → drag to VBUS on Pico
- Click the Signal (orange) pin on servo → drag to GP15 on Pico
Why GP15?
- You can use any GPIO pin that supports PWM
- GP15 is commonly used but GP0-GP28 all support PWM
- The example code uses GP15, but you can change it
Step 5: Understanding Servo Control with PWM
How Servo Motors Work:
Servos are controlled by PWM signals:
- Frequency: 50 Hz (20ms period)
- Pulse Width determines angle:
- 1ms (5% duty) = 0° (minimum angle)
- 1.5ms (7.5% duty) = 90° (center)
- 2ms (10% duty) = 180° (maximum angle)
CODE:
from machine import Pin, PWM
import time
servo = PWM (Pin (15))
servo.freq (50)
while True:
servo.duty_ns (500000)
time. sleep_ms(500)
servo.duty_ns (1500000)
time. sleep_ms(500)
servo.duty_ns (2500000)
time. sleep_ms(500)
servo.duty_ns (1500000)
time. sleep_ms(500)
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