lcd display python free sample

This repository contains all the code for interfacing with a 16x2 character I2C liquid-crystal display (LCD). This accompanies my Youtube tutorial: Raspberry Pi - Mini LCD Display Tutorial.

During the installation, pay attention to any messages about python and python3 usage, as they inform which version you should use to interface with the LCD driver. For example:

It is possible to define in CG RAM memory up to 8 custom characters. These characters can be prompted on LCD the same way as any characters from the characters table. Codes for the custom characters are unique and as follows:

For example, the hex code of the symbol ö is 0xEF, and so this symbol could be printed on the second row of the display by using the {0xEF} placeholder, as follows:

If you want to combine placeholder to write a symbol {0xFF} with the native Python placeholder {0} for inserting dome data into text, escape the non-native placeholders. Here is an example:

Once you are done editing a demo_*.py file or writing your own Python script, follow the instructions on this section to run the script in the background. First, however, ensure that the script (e.g., script.py) has at least permission to be executed, as follows:

If you plan on using an LCD with your Raspberry Pi, there’s a good chance you’ll need to program it in Python at some point. Python is probably the most popular programming language for coding on the Raspberry Pi, and many of the projects and examples you’ll find are written in Python.

In this tutorial, I’ll show you how to connect your LCD and program it in Python, using the RPLCD library. I’ll start with showing you how to connect it in either 8 bit mode or 4 bit mode. Then I’ll explain how to install the library, and provide examples for printing and positioning text, clearing the screen, and controlling the cursor. I’ll also give you examples for scrolling text, creating custom characters, printing data from a sensor, and displaying the date, time, and IP address of your Pi.

You can also connect the LCD via I2C, which uses only two wires, but it requires some extra hardware. Check out our article, How to Setup an I2C LCD on the Raspberry Pi to see how.

There are two ways to connect the LCD to your Raspberry Pi – in 4 bit mode or 8 bit mode. 4 bit mode uses 6 GPIO pins, while 8 bit mode uses 10. Since it uses up less pins, 4 bit mode is the most common method, but I’ll explain how to set up and program the LCD both ways.

Each character and command is sent to the LCD as a byte (8 bits) of data. In 8 bit mode, the byte is sent all at once through 8 data wires, one bit per wire. In 4 bit mode, the byte is split into two sets of 4 bits – the upper bits and lower bits, which are sent one after the other over 4 data wires.

Theoretically, 8 bit mode transfers data about twice as fast as 4 bit mode, since the entire byte is sent all at once. However, the LCD driver takes a relatively long time to process the data, so no matter which mode is being used, we don’t really notice a difference in data transfer speed between 8 bit and 4 bit modes.

If this is your first time writing and running a Python program, you might want to read How to Write and Run a Python Program on the Raspberry Pi, which will explain everything you need to know to run the examples below.

The RPLCD library can be installed from the Python Package Index, or PIP. It might already be installed on your Pi, but if not, enter this at the command prompt to install it:

The example programs below use the Raspberry Pi’s physical pin numbers, not the BCM or GPIO numbers. I’m assuming you have your LCD connected the way it is in the diagrams above, but I’ll show you how to change the pin connections if you need to.

Let’s start with a simple program that will display “Hello world!” on the LCD. If you have a different sized LCD than the 16×2 I’m using (like a 20×4), change the number of columns and rows in line 2 of the code. cols= sets the number of columns, and rows= sets the number of rows. You can also change the pins used for the LCD’s RS, E, and data pins. The data pins are set as pins_data=[D0, D1, D2, D3, D4, D5, D6, D7].

The text can be positioned anywhere on the screen using lcd.cursor_pos = (ROW, COLUMN). The rows are numbered starting from zero, so the top row is row 0, and the bottom row is row 1. Similarly, the columns are numbered starting at zero, so for a 16×2 LCD the columns are numbered 0 to 15. For example, the code below places “Hello world!” starting at the bottom row, fourth column:

The RPLCD library provides several functions for controlling the cursor. You can have a block cursor, an underline cursor, or a blinking cursor. Use the following functions to set the cursor:

Text will automatically wrap to the next line if the length of the text is greater than the column length of your LCD. You can also control where the text string breaks to the next line by inserting \n\r where you want the break to occur. The code below will print “Hello” to the top row, and “world!” to the bottom row.

This program will print the IP address of your ethernet connection to the LCD. To print the IP of your WiFi connection, just change eth0 in line 19 to wlan0:

Each character on the LCD is an array of 5×8 of pixels. You can create any pattern or character you can think of, and display it on the screen as a custom character. Check out this website for an interactive tool that creates the bit array used to define custom characters.

First we define the character in lines 4 to 12 of the code below. Then we use the function lcd.create_char(0-7, NAME) to store the character in the LCD’s CGRAM memory. Up to 8 (0-7) characters can be stored at a time. To print the custom character, we use lcd.write_string(unichr(0)), where the number in unichr() is the memory location (0-7) defined in lcd.create_char().

To demonstrate how to print data from a sensor, here’s a program that displays the temperature from a DS18B20 Digital Temperature Sensor. There is some set up to do before you can get this to work on the Raspberry Pi, so check out our tutorial on the DS18B20 to see how.

In general, you take the input variable from your sensor and convert it to an integer to perform any calculations. Then convert the result to a string, and output the string to the display using lcd.write_string(sensor_data()):

Well, that about covers most of what you’ll need to get started programming your LCD with Python. Try combining the programs to get some interesting effects. You can display data from multiple sensors by printing and clearing the screen or positioning the text. You can also make fun animations by scrolling custom characters.

In the previous project of the Raspberry Pi Series, I have shown you how to blink an LED using Raspberry Pi and Python Program. Moving forward in the series, in this project, I’ll show you the interfacing 16×2 LCD with Raspberry Pi.

In this project, you can see all the steps for Interfacing a 16×2 LCD with Raspberry Pi like circuit diagram, components, working, Python Program and explanation of the code.

Even though the Raspberry Pi computer is capable of doing many tasks, it doesn’t have a display for implementing it in simple projects. A 16×2 Alphanumeric Character LCD Display is a very important types of display for displaying some basic and vital information.

A 16×2 LCD is one of the most popular display modules among hobbyists, students and even electronics professionals. It supports 16 characters per row and has two such rows. Almost all the 16×2 LCD Display Modules that are available in the market are based on the Hitachi’s HD44780 LCD Controller.

The pin description in the above table shows that a 16×2 LCD has 8 data pins. Using these data pins, we can configure the 16×2 LCD in either 8 – bit mode or 4 – bit mode. I’ll show the circuit diagram for both the modes.

In 8 – bit mode, all the 8 data pins i.e. D0 to D7 are used for transferring data. This type of connection requires more pins on the Raspberry Pi. Hence, we have opted for 4 – bit mode of LCD. The circuit diagram (with Fritzing parts) is shown below.

The following image shows the wiring diagram of the featured circuit of this project i.e. LCD in 4 – bit mode. In this mode, only 4 data pins i.e. D4 to D7 of the LCD are used.

NOTE: In this project, we have used the 4 – bit mode of the 16×2 LCD display. The Python code explained here is also related to this configuration. Slight modifications are needed in the Python Program if the circuit is configured in 8 – bit mode.

The design of the circuit for Interfacing 16×2 LCD with Raspberry Pi is very simple. First, connect pins 1 and 16 of the LCD to GND and pins 2 and 15 to 5V supply.

Then connect a 10KΩ Potentiometer to pin 3 of the LCD, which is the contrast adjust pin. The three control pins of the LCD i.e. RS (Pin 4), RW (Pin 5) and E (Pin 6) are connected to GPIO Pin 7 (Physical Pin 26), GND and GPIO Pin 8 (Physical Pin 24).

Now, the data pins of the LCD. Since we are configuring the LCD in 4 – bit mode, we need only 4 data pins (D4 to D7). D4 of LCD is connected to GPIO25 (Physical Pin 22), D5 to GPIO24 (Physical Pin 18), D6 to GPIO24 (Physical Pin 16) and D7 to GPIO18 (Physical Pin 12).

The working of project for Interfacing 16×2 LCD with Raspberry Pi is very simple. After making the connections as per the circuit diagram, login to your Raspberry Pi using SSH Client like Putty in Windows.

I’ve created a folder named “Python_Progs” on the desktop of the Raspberry Pi. So, I’ll be saving my Python Program for Interfacing 16 x 2 LCD with Raspberry Pi in this folder.

Using “cd” commands in the terminal, change to this directory. After that, open an empty Python file with name “lcdPi.py” using the following command in the terminal.

Now, copy the above code and paste it in the editor. It is important to properly use the Tab characters as they help in grouping the instructions in Python.

Save the file and close the editor. To test the code, type the following command in the terminal. If everything is fine with your connections and Python Program, you should be able to see the text on the 16×2 LCD.

First, I’ve imported the RPi.GPIO Python Package as GPIO (here after called as GPIO Package) and sleep from time package. Then, I have assigned the pin for LCD i.e. RS, E, D4, D5, D6 and D7. The numbering scheme I followed is GPIO or BCM Scheme.

Finally, using some own functions like lcd_init, lcd_string, lcd_display, etc. I’ve transmitted the data to be printed from the Raspberry Pi to the 16×2 LCD Module.

By interfacing 16×2 LCD with Raspberry Pi, we can have a simple display option for our raspberry Pi which can display some basic information like Date, Time, Status of a GPIO Pin, etc.

Many simple and complex application of Raspberry Pi like weather station, temperature control, robotic vehicles, etc. needs this small 16×2 LCD Display.

This is a new Pi Pico display from Waveshare with many more pixels. It is a 2inch LCD display module, designed for Raspberry Pi Pico, with an embedded ST7789VW driver, 65K RGB colours, 320x240 pixels and an SPI interface. A Pi Pico can be plugged into the rear of the screen for very easy connection without any soldering. It sports 4 simple button switches for user input. It is bright, colourful and easy to program. The makers supply an example program (see below), which includes the display driver, making it very easy to get started. The manufacturer"s wiki can be found at:

ExecStart is the command (or set of commands) used to start our program. Notice that we are using absolute paths to the version of Python we want as well as the location of our program.

Under [Service], we specify some environment variables. We want to connect to our primary display (this assumes only one display is connected to our Pi), so we set DISPLAY to :0, and we tell our application where to find the necessary credentials to use the X windows system with XAUTHORITY. ExecStart is the command we want to run (starting our Python clock program, in this case).

Reboot with sudo reboot to verify that your program works. You should see your Python clock program running after you have logged into your graphical desktop.

This starts a new bash shell, runs your program, and redirects the output (stdout) to a new clock.log text file. The 2>&1 command says that any errors (stderr) should also be redirected (written to) the same log file. Any output (e.g. from Python print() commands) or errors will then be saved to clock.log. You can view the log with the following command (note that you might need to stop the service and program before viewing the log):

Because your systemd unit file will likely run before .bashrc can alias the command python to Python 3, you might need to explicitly call the python3 command. To do that, just make sure that your call to Python is an absolute file location, for example, /usr/bin/python3.

For some services, like our clock.service example, you will need to stop the service before stopping the program. That"s because even if you stop the program (e.g. our Python GUI clock), the service will simply restart it 10 seconds later! To stop a service, enter the following command:

ps -ax tells Linux to list out all the currently processes. We send that output to grep, which allows us to search for the keyword "python" (feel free to change it to the name of your program). Find the process ID (PID) number to the left of the listed process, and use the kill command to terminate that process:

These displays all plug directly into the pins of your Pico and are programmed in the same way but require slightly different driver code, supplied by Waveshare via their Wiki pages.

All these displays need some memory in the Pico, a "buffer", to hold the data to be displayed on the screen. As the number of pixels increases so does the size of this buffer requirement and the space available for code decreases. As the pixel size gets smaller the basic text gets progressively harder the read as it is so small.

For this tutorial we are going to use the 1.44” 128x128 display as it provides a good compromise between basic text size, number of pixels on the display for graphics, buffer size, input buttons and price. The code is easily converted to run on the other displays.

This is simple – just push the Pico’s pins into the socket on the rear of the display and use the USB cable to connect it to your computer. Make sure you have it the right way round - the USB end is marked on the bottom of the board. Once Thonny has been installed we are ready to go.

The first line initialises the display using the driver code at the start of the program. It calls the display device LCD, but we could call it something different – but using LCD makes typing code easier!

All of these Waveshare displays use 16-bit colour codes to mix colours by varying the brightness ratios of red, green and blue in each pixel. As human eyes are more sensitive to green light, an extra bit is given to the green component. This code is called RGB565 with 5 bits for red and blue and 6 bits for green.

At this point we ported the code to work on the other four displays and found that they use a slightly different system - the blue and red bits have been swapped over:

To make things easy we are providing minimum setup programs for each of the 5 boards. Each program includes the correct screen driver, sets up the buttons and joystick, if available, and includes the correct version of the colour(R, G ,B) function. It also displays a 3-line colour check at the start.

Each program contains the screen driver code, sets up the buttons/joystick and sets the width and height variables correctly, loads the essential libraries, defines the colour(R, G, B) and clear(c) procedures. It then displays some colour checking text.

2.Near the centre of the screen, on a dark grey background, display your name, in red, and post/zip code, in cyan. Indent the post code by 10 pixels more than your name.

At this point we need to separate the Pico and the display. We need access to some of the GPIO pins to attach three 10 K 0hm potentiometers. You could press the Pico into a breadboard or, more conveniently use a Pico Decker, which has all the Pico pins neatly numbered and named. The circuit is shown in the diagram.

If your display has buttons, you will not need the extra one here. Connect up the SPI, power and button pins from your display (the product page/Wiki page for your particular display will show the pinout).

Turn all three pots in turn and check that the range of each is 0 – 255. The 1.44” display is 128 x 128 so we added these lines just above the loop and updated the loop.

This article was written by Tony Goodhew. Tony is a retired teacher of computing who starting writing code back in 1968 when it was called programming - he started with FORTRAN IV on an IBM 1130! An active Raspberry Pi community member, his main interests now are coding in MicroPython, travelling and photography.

I was searching for the 16x2 LCD Interfacing with Raspberry Pi and found that there are not many Instructions About interfacing the simple Connection anywhere in the Community Blogs Hence, I decided to create a small instruction to interface the LCD with Raspberry Pi using Adafruit CharLCD Library.

To interface the LCD with Raspberry Pi we need to install The Circuit Python and CharLCD Library.Firstly, you need to install the circuit python Libraries. The following Link shows How to Install Circuit Python On the raspberry pi platform

As soon as we have this API key, we can move to the hardware configuration and connect the LCD screen to our Raspberry Pi. You should turn the Raspberry Pi off while you make the wire connection.

This hardware connection will make the LCD screen be on full brightness and full contrast. The brightness level is not a problem, but contrast is because we won’t be able to see the characters on the screen.

At this point, we can turn on our Raspberry Pi and we should see the LCD screen alive. With the help of variable resistance we should be able to control the contrast.

In a new folder, run the command npm init -y to set up a new npm package, followed by the command npm install lcd node-fetch to install these 2 necessary dependencies.lcd will be used to communicate with the LCD Screen

Writing on the screen is a piece of cake using the lcd module. This library acts as a layer of abstraction over how we communicate with the device. In this way we don’t need to micro-manage each command individually.

The keys cols and rows represent the number of columns and rows of our LCD display. 16x2 is the one I used in this example. If your LCD has just 8 columns and 1 row, then replace 16 and 2 with your values.

At this point, you can use this function and print something on your display. writeToLcd(0,0,"Hello World") should print the message Hello World on the first row starting from the first column.

ClimaCell provides a lot of weather data information, but also air quality and pollen, fire and other information. The data is vast, but keep in mind that your LCD screen only has 16 columns and 2 rows – that’s just 32 characters.

To print the time in the upper right corner, we must first calculate the starting column so that the text fits snugly. For this we can use the next formula total columns number minus text to display length

The LCD setting is asynchronous, so we must use the method lcd.on() provided by the related library, so we know when the LCD has been initialized and is ready to be used.

Another best practice in embedded systems is to close and free the resources that you use. That’s why we use the SIGNINT event to close the LCD screen when the program is stopped. Other events like this one include:SIGUSR1 and SIGUSR2 - to catch "kill pid” like nodemon restart

From this point you can customize your new device however you want. If you find this weather data important for you (or any other data from ClimaCell, like air pollution, pollen, fire index or road risk), you can create a custom case to put the Raspberry Pi and the LCD display in it. Then after you added a battery you can place the device in your house.

displays ‘text’ starting at grid (x, y) where the grid is made of cells 8 pixels wide and 10 pixels tall such that the EV3 display is 22 columns wide and 12 rows tall. The size of the grid cells does not depend on the size of the chosen font. There is no fixed-width font available which has dimensions that match the grid cell size and therefore I recommend that you avoid using this function and that you stick to using text_pixels() instead. Even if a font were available that matches the grid cell dimensions it would be a very small font (size 10, meaning 10 pixels tall) and would be very hard to read.

The script makes use of a standard Python functionwrap(text, width) whichwraps the single paragraph in text(a string) so every line is at most widthcharacters long. It returns a listof output lines i.e. a list of strings. For example