Arduino MicroPython LCD I2C
This guide shows you how to use an Arduino with a 16x2 LCD I2C using MicroPython. You will learn:
- How to connect an LCD I2C to an Arduino
- How to write MicroPython code for Arduino to display text on the LCD I2C
- How to write MicroPython code for Arduino to display numbers on the LCD I2C
- How to write MicroPython code for Arduino to display custom characters on the LCD I2C
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables.
Additionally, some of these links are for products from our own brand, DIYables.
Overview of LCD I2C 16x2
The 16x2 LCD I2C is a screen with 16 columns and 2 rows. It has an I2C interface and comes with a potentiometer to adjust the screen's contrast.
Pinout
The LCD I2C uses an I2C interface and includes 4 pins.
- GND pin: connect to GND (0 volts).
- VCC pin: connect to VCC for power (5 volts).
- SDA pin: transfers I2C data signal.
- SCL pin: transfers I2C clock signal.
LCD Coordinate
The LCD I2C 16x2 includes 16 columns and 2 rows. The numbering of both columns and rows begins from 0.
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
| LCD I2C | Arduino Giga |
|---|---|
| VCC | Vin 5V |
| GND | GND |
| SDA | D9 |
| SCL | D8 |
Arduino MicroPython Code
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-lcd-i2c
"""
from machine import I2C, Pin
from DIYables_MicroPython_LCD_I2C import LCD_I2C
import utime
# The I2C address of your LCD (Update if different)
I2C_ADDR = 0x27 # Use the address found using the I2C scanner
# Define the number of rows and columns on your LCD
LCD_ROWS = 2
LCD_COLS = 16
# Initialize I2C
i2c = I2C(1) # Arduino Giga R1 WiFi I2C1 pins: SCL-D8, SDA-D9
# Initialize LCD
lcd = LCD_I2C(i2c, I2C_ADDR, LCD_ROWS, LCD_COLS)
# Setup function
lcd.backlight_on()
lcd.clear()
# Main loop function
while True:
lcd.clear()
lcd.set_cursor(3, 0) # Move the cursor to column 3, row 0 (first row)
lcd.print("DIYables")
lcd.set_cursor(0, 1) # Move the cursor to column 0, row 1 (second row)
lcd.print("www.diyables.io")
utime.sleep(2)
lcd.clear()
lcd.set_cursor(0, 0) # Move to the beginning of the first row
lcd.print("Int: ")
lcd.print(str(1234)) # Print integer
lcd.set_cursor(0, 1) # Move to the beginning of the second row
lcd.print("Float: ")
lcd.print(str(56.78)) # Print float
utime.sleep(2)
Detailed Instructions
Here’s instructions on how to run the above MicroPython code on Arduino with Thonny IDE:
- Make sure Thonny IDE is installed on your computer.
- Make sure MicroPython firmware is installed on your Arduino board.
- If you are new to Arduino with MicroPython, see the Getting Started with Arduino and MicroPython.
- Connect the LCD I2C display to the Arduino according to the provided diagram.
- Connect the Arduino board to your computer with a USB cable.
- Open Thonny IDE and go to Tools Options.
- Under the Interpreter tab, select MicroPython (generic) from the dropdown menu.
- Select the COM port corresponding to your Arduino board (e.g., COM33 on Windows or /dev/ttyACM0 on Linux).
- Navigate to the Tools Manage packages on the Thonny IDE.
- Search “DIYables-MicroPython-LCD-I2C”, then find the LCD I2C library created by DIYables.
- Click on DIYables-MicroPython-LCD-I2C, then click Install button to install LCD I2C library.
- Copy the provided Arduino MicroPython code and paste it into Thonny's editor.
- Save the MicroPython code to your Arduino by:
- Clicking the Save button or pressing Ctrl+S.
- In the save dialog, choose MicroPython device and name the file main.py.
- Click the green Run button (or press F5) to execute the code.
- Check out the result on the LCD display.
Do More with LCD
Displaying Custom Character on LCD
To display special characters or symbols (like a heart or an angry bird) on an LCD, you need to use a character generator because the lcd.print() function can only show standard ASCII characters.
The 16x2 LCD can display 32 characters, with 16 positions per line over 2 lines. Each character is made up of 40 pixels, arranged in 8 rows and 5 columns.
The character generator makes a character (40 pixels). You just need to follow these steps:
Click on each pixel to select/deselect
Copy below custom character code
Replace the heart in the below code
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-lcd-i2c
"""
from machine import I2C, Pin
from DIYables_MicroPython_LCD_I2C import LCD_I2C
import utime
# The I2C address of your LCD (Update if different)
I2C_ADDR = 0x27
# Define the number of rows and columns on your LCD
LCD_ROWS = 2
LCD_COLS = 16
# Initialize I2C
i2c = I2C(1) # Arduino Giga R1 WiFi I2C1 pins: SCL-D8, SDA-D9
# Initialize LCD
lcd = LCD_I2C(i2c, I2C_ADDR, LCD_ROWS, LCD_COLS)
# Define custom character 0 (heart shape)
heart = [
0b00000,
0b01010,
0b11111,
0b11111,
0b01110,
0b00100,
0b00000,
0b00000
]
# Create the custom character at location 0
lcd.custom_char(0, heart)
# Display the custom character
lcd.print("Custom Char: ")
lcd.print_custom_char(0) # Display the custom character stored at location 0
Result shown on the screen:
Displaying Multiple custom characters on LCD
We can create up to 8 special characters (from 0 to 7). Here is how to make and show three of these characters.
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-lcd-i2c
"""
from machine import I2C, Pin
from DIYables_MicroPython_LCD_I2C import LCD_I2C
import utime
# The I2C address of your LCD (Update if different)
I2C_ADDR = 0x27
# Define the number of rows and columns on your LCD
LCD_ROWS = 2
LCD_COLS = 16
# Initialize I2C
i2c = I2C(1) # Arduino Giga R1 WiFi I2C1 pins: SCL-D8, SDA-D9
# Initialize LCD
lcd = LCD_I2C(i2c, I2C_ADDR, LCD_ROWS, LCD_COLS)
# Define custom character 0 (heart shape)
heart = [
0b00000,
0b01010,
0b11111,
0b11111,
0b01110,
0b00100,
0b00000,
0b00000
]
# Define custom character 1 (arrow pointing upwards)
arrow_up = [
0b00100,
0b01110,
0b11111,
0b00100,
0b00100,
0b00100,
0b00100,
0b00100
]
# Define custom character 2 (arrow pointing downwards)
arrow_down = [
0b00100,
0b00100,
0b00100,
0b00100,
0b00100,
0b11111,
0b01110,
0b00100
]
# Create the custom character at location 0
lcd.custom_char(0, heart)
lcd.custom_char(1, arrow_up)
lcd.custom_char(2, arrow_down)
# Display the custom character
lcd.set_cursor(0, 0) # Move the cursor to column 0, row 0 (first row)
lcd.print_custom_char(0) # Display the custom character stored at location 0
lcd.set_cursor(5, 0) # Move the cursor to column 5, row 0 (first row)
lcd.print_custom_char(1) # Display the custom character stored at location 0
lcd.set_cursor(10, 0) # Move the cursor to column 10, row 0 (first row)
lcd.print_custom_char(2) # Display the custom character stored at location 0
Result shown on LCD screen:
Summary: How to Use Custom Characters on an LCD
- Create binary code: Use the provided tool to generate the binary code for your custom character.
- Write down the code: Copy the binary code from the tool.
heart = [
0b00000,
0b01010,
0b11111,
0b11111,
0b01110,
0b00100,
0b00000,
0b00000
]
- Create a custom character and position it at a number from 0 to 7
lcd.custom_char(0, heart)
- Show a custom symbol on the LCD display.
lcd.print_custom_char(0) # Display the custom character stored at location 0
Troubleshooting on LCD I2C
If you're having trouble displaying text on your LCD I2C screen, try these steps:
- Adjust the brightness: Turn the potentiometer on the back of the LCD to change the brightness.
- Check the I2C address: The I2C address may differ between manufacturers. Common addresses are 0x27 and 0x3F. Try these addresses to see if they work. If not, run the I2C scanner code on the Arduino to find the correct I2C address.
"""
This Arduino MicroPython script was developed by newbiely.com
This Arduino MicroPython script is made available for public use without any restriction
For comprehensive instructions and wiring diagrams, please visit:
https://newbiely.com/tutorials/arduino-micropython/arduino-micropython-lcd-i2c
"""
from machine import I2C, Pin
import utime
i2c = I2C(1)
print('Scanning I2C bus...')
devices = i2c.scan()
if len(devices) == 0:
print("No I2C devices found")
else:
print('I2C devices found:',len(devices))
for device in devices:
print("Decimal address: ",device," | Hex address: ",hex(device))
utime.sleep(2)
The result shown in the Shell at the bottom of Thonny:
Shell x
>>> %Run -c $EDITOR_CONTENT
MPY: soft reboot
Scanning I2C bus...
I2C devices found: 1
Decimal address: 39 | Hex address: 0x27
MicroPython (generic) • Giga Virtual Comm Port in FS Mode @ COM33 ≡