Raspberry Pi - Ultrasonic Sensor - LCD
This tutorial instructs you how to use Raspberry Pi to obtain the distance from an ultrasonic sensor and display it on an LCD I2C.
Hardware Preparation
| 1 | × | Raspberry Pi 4 Model B | |
| 1 | × | LCD I2C | |
| 1 | × | Ultrasonic Sensor | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) Screw Terminal Adapter for Raspberry Pi |
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Overview of Ultrasonic Sensor and LCD
If you are unfamiliar with ultrasonic sensor and LCD (including pinout, how it works, and how to program), the following tutorials can help you learn:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Raspberry Pi Code
Detailed Instructions
- Make sure you have Raspbian or any other Raspberry Pi compatible operating system installed on your Pi.
- Make sure your Raspberry Pi is connected to the same local network as your PC.
- Make sure your Raspberry Pi is connected to the internet if you need to install some libraries.
- If this is the first time you use Raspberry Pi, See how to set up the Raspberry Pi
- Connect your PC to the Raspberry Pi via SSH using the built-in SSH client on Linux and macOS or PuTTY on Windows. See to how connect your PC to Raspberry Pi via SSH.
- Make sure you have the RPi.GPIO library installed. If not, install it using the following command:
sudo apt-get update
sudo apt-get install python3-rpi.gpio
- Prior to utilizing the LCD I2C with a Raspberry Pi, we need to enable I2C interface on Raspberry Pi. See How to enable I2C interface on Raspberry Pi
- Install the LCD I2C library by running the following command:
pip install lcddriver
- Create a Python script file ultrasonic_lcd.py and add the following code:
# This Raspberry Pi code was developed by newbiely.com
# This Raspberry Pi code is made available for public use without any restriction
# For comprehensive instructions and wiring diagrams, please visit:
# https://newbiely.com/tutorials/raspberry-pi/raspberry-pi-ultrasonic-sensor-lcd
from gpiozero import DistanceSensor
from lcddriver import lcd
from time import sleep
# GPIO pins for ultrasonic sensor
TRIGGER_PIN = 16
ECHO_PIN = 20
# I2C address 0x27, 16 columns, 2 rows
LCD = lcd()
# Create ultrasonic sensor instance
ultrasonic_sensor = DistanceSensor(trigger=TRIGGER_PIN, echo=ECHO_PIN)
def display_distance(distance):
LCD.lcd_clear()
LCD.lcd_display_string(f"Distance: {distance:.2f} m", 1)
try:
while True:
distance = ultrasonic_sensor.distance
display_distance(distance)
sleep(0.5) # Sleep for 500 milliseconds
except KeyboardInterrupt:
pass
finally:
LCD.lcd_clear()
- Save the file and run the Python script by executing the following command in the terminal:
python3 ultrasonic_lcd.py
The script runs in an infinite loop continuously until you press Ctrl + C in the terminal.
Code Explanation
Check out the line-by-line explanation contained in the comments of the source code!
※ NOTE THAT:
- If the LCD is not displaying anything, take a look at Troubleshooting on LCD I2C.
- The code provided is for educational purposes. The ultrasonic sensor is very sensitive to noise, so if you plan to use it in a real-world application, you should filter the noise from the ultrasonic sensor. See how to filter noise for ultrasonic sensor for more information.