🌡️ Raspberry Pi – Sensors & Motor Control (2025 Hands-On Guide for GPIO Projects)

---

🧲 Introduction – Control the Physical World with Sensors & Motors

Interfacing sensors and motors with Raspberry Pi brings your projects to life. From measuring temperature to controlling servo motors, this guide shows you how to connect, power, and program essential hardware components using Raspberry Pi’s GPIO.

🎯 In this guide, you’ll learn:

• How to connect and read data from sensors
• How to control DC motors, servos, and relays
• Sample Python code using GPIO and gpiozero
• Real-world examples: motion detection, automation, robotics

---

🧰 Components Required

🧪 Component	🔧 Quantity
Temperature Sensor (e.g., DHT11/22)	1
Ultrasonic Sensor (HC-SR04)	1
DC Motor / Servo Motor	1 or more
L298N Motor Driver Module	1
Raspberry Pi + Breadboard	1
Jumper Wires & Power Supply	As needed

✅ Optional: External 5V power source for motors

---

🌡️ Reading Sensors – DHT11/22 Example

✅ Wiring:

Sensor Pin	Connects To
VCC	3.3V (Pin 1)
GND	GND (Pin 6)
DATA	GPIO4 (Pin 7)

✅ Install Library:

pip3 install Adafruit_DHT

✅ Python Code:

import Adafruit_DHT

sensor = Adafruit_DHT.DHT22
pin = 4  # GPIO4

humidity, temperature = Adafruit_DHT.read_retry(sensor, pin)

if humidity is not None and temperature is not None:
    print(f'Temp: {temperature:.1f}°C, Humidity: {humidity:.1f}%')
else:
    print('Failed to read sensor')

✅ Use this setup to monitor room temperature or trigger fans.

---

📏 Distance Sensor – HC-SR04 (Ultrasonic)

✅ Wiring:

Pin	Connects To
VCC	5V (Pin 2)
GND	GND (Pin 6)
TRIG	GPIO23 (Pin 16)
ECHO	GPIO24 (Pin 18)

✅ Python Code:

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
TRIG = 23
ECHO = 24

GPIO.setup(TRIG, GPIO.OUT)
GPIO.setup(ECHO, GPIO.IN)

GPIO.output(TRIG, False)
time.sleep(2)

GPIO.output(TRIG, True)
time.sleep(0.00001)
GPIO.output(TRIG, False)

while GPIO.input(ECHO) == 0:
    pulse_start = time.time()

while GPIO.input(ECHO) == 1:
    pulse_end = time.time()

pulse_duration = pulse_end - pulse_start
distance = pulse_duration * 17150
distance = round(distance, 2)

print(f"Distance: {distance} cm")
GPIO.cleanup()

🧠 Great for robotics, obstacle detection, and automation triggers.

---

🔧 Motor Control with L298N Driver

✅ Connect L298N to Raspberry Pi:

L298N Pin	Connects To
IN1	GPIO17 (Pin 11)
IN2	GPIO18 (Pin 12)
ENA	Jumper or GPIO PWM
VCC	External 9V battery
GND	Raspberry Pi GND

✅ Python Code:

import RPi.GPIO as GPIO
import time

IN1 = 17
IN2 = 18

GPIO.setmode(GPIO.BCM)
GPIO.setup(IN1, GPIO.OUT)
GPIO.setup(IN2, GPIO.OUT)

# Motor Forward
GPIO.output(IN1, GPIO.HIGH)
GPIO.output(IN2, GPIO.LOW)
time.sleep(2)

# Motor Reverse
GPIO.output(IN1, GPIO.LOW)
GPIO.output(IN2, GPIO.HIGH)
time.sleep(2)

GPIO.cleanup()

✅ This controls direction. Use PWM for speed control.

---

🌀 Servo Motor Control

✅ Connect Servo:

Servo Wire	Connects To
VCC	5V (Pin 2)
GND	GND (Pin 6)
Signal	GPIO17 (Pin 11)

✅ Python Code:

from gpiozero import Servo
from time import sleep

servo = Servo(17)

while True:
    servo.min()
    sleep(1)
    servo.max()
    sleep(1)

✅ Ideal for robotic arms, pan/tilt cams, and automation projects.

---

🧪 Sensor + Motor Use Cases

🤖 Project Idea	📝 Description
Temperature-Controlled Fan	Sensor triggers motor when temp exceeds limit
Motion Detector Alarm	Ultrasonic or PIR sensor triggers buzzer/motor
Smart Curtain Opener	Servo adjusts curtain via light sensor input
Obstacle Avoidance Car	Ultrasonic sensor controls motor directions

---

📌 Summary – Recap & Next Steps

Interfacing sensors and motors makes Raspberry Pi a powerful tool for real-world interaction. With GPIO, Python, and a few components, you can automate, detect, and move things intelligently.

🔍 Key takeaways:

• Use GPIO to connect sensors like DHT22, HC-SR04, etc.
• Control DC motors or servos using motor drivers and Python
• Combine input (sensors) and output (motors) for dynamic projects
• Use libraries like gpiozero, RPi.GPIO, Adafruit_DHT for ease

⚙️ Real-world relevance: Perfect for home automation, smart farming, robotics, and interactive systems.

---

❓ FAQs – Raspberry Pi Sensors & Motors

❓ Do I need an external power source for motors?

✅ Yes, for DC motors and servos, it’s best to use a separate 5–12V supply to avoid stressing the Pi.

---

❓ Can I read multiple sensors at once?

✅ Yes. Just assign each sensor to a different GPIO pin and manage them with Python loops or threads.

---

❓ Is it safe to connect a 5V sensor to GPIO?

✅ Only if it outputs 3.3V logic or uses a voltage divider or logic level converter.

---

❓ What’s the difference between PWM and GPIO output?

✅ GPIO output is on/off, while PWM can simulate analog values (e.g., motor speed, servo angle).

---

❓ Which library is best for GPIO motor control?

✅ Use RPi.GPIO for full control or gpiozero for beginner-friendly syntax.

---

Share Now :