How to Control a Servo Motor

Steps to Control a Servo Motor

1

Open OmniBoard Studio and create a new project.

2

Build the block diagram to sweep the servo from 0° to 180° and back.

Try to build the diagram yourself, or click here to see one solution. ▼

• ● Place a Start block and connect it to a While True block.
• ● Add a Set Servo Angle block set to 0°, followed by a Timer block (e.g. 1000 ms).
• ● Add a second Set Servo Angle block set to 90°, followed by another Timer block.
• ● Add a third Set Servo Angle block set to 180°, followed by a Timer block. The loop will then return to 0° and repeat the sweep.

3

Wire the servo motor to your microcontroller.

• ● A standard servo has three wires: Power (usually red) → connect to 5V, Ground (usually brown or black) → connect to GND, Signal (usually orange or yellow) → connect to a PWM-capable GPIO pin.
• ● Note: if the servo draws too much current, use an external 5V power supply for the servo power wire and share only the ground with the microcontroller.

4

Compile the code and upload it to your microcontroller.

5

Watch the servo arm sweep from 0° to 90° to 180° and back in a continuous loop!

Bonus Information

• Here is simplified MicroPython code for sweeping a servo motor:

import machine
import time

# Servo control on GPIO pin 5 at 50 Hz (standard servo frequency)
pwm = machine.PWM(machine.Pin(5), freq=50)

def set_angle(angle):
    # Convert angle (0-180) to duty cycle (approx 40-115 for ESP32)
    duty = int(40 + (angle / 180) * 75)
    pwm.duty(duty)

while True:
    set_angle(0)    # Move to 0 degrees
    time.sleep(1)
    set_angle(90)   # Move to 90 degrees
    time.sleep(1)
    set_angle(180)  # Move to 180 degrees
    time.sleep(1)
                

• And here is simplified code for Python (Raspberry Pi):

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setup(5, GPIO.OUT)
pwm = GPIO.PWM(5, 50)  # 50 Hz for servo
pwm.start(0)

def set_angle(angle):
    duty = 2 + (angle / 18)  # Convert angle to duty cycle
    pwm.ChangeDutyCycle(duty)

while True:
    set_angle(0)
    time.sleep(1)
    set_angle(90)
    time.sleep(1)
    set_angle(180)
    time.sleep(1)
                

• What is a servo motor?
• A servo motor is a motor with a built-in gearbox and control circuit that lets you precisely set its rotational position. Most hobby servos rotate between 0° and 180°. They are commonly used in robotics, RC vehicles, and automation projects.
• How does a servo receive position commands?
• A servo is controlled by a PWM signal at 50 Hz. The pulse width (typically 1 ms to 2 ms) tells the servo where to go: a 1 ms pulse moves it to 0°, a 1.5 ms pulse moves it to 90°, and a 2 ms pulse moves it to 180°.