raspberry pi lcd display gpio free sample

If you only use 4bit data then with the Register Select and enable pins you only need 6 gpio. You will have to connect read/write to ground rather a gpio pin.

Hello and thank you very much for your feedback: unfortunately I"m a total newbye about GPIO and LCD screens, so I could not understand the first part of your answer.

So that is a HDD44780 compatible LCD which is what I assumed you were talking about it clearly states only 6 digital lines required, so that"s 6 gpio the pi gpio being digital.

Now there are lots and lots of examples on line https://www.google.com/search?q=16x2+lc ... =firefox-b of how to use this type of lcd with the pi you are just going to have to modify which ever example you choose to follow to use the free gpio you have.

it also works with python2 and 3 as long as you install it for which ever version of python you intend to use, it also has the option for you to choose which gpio pins you want to use for which functions ( remember I said 4bit data then with the Register Select and enable pins you only need 6 gpio ).

you might benefit from installing it using one of the examples so you get to understand how it works, of course you will have remove the vga add on first then once you understand you can change the gpio used to the ones you have free once the vga add on is installed.

I"ve seen some LCD2USB boards that, of course, are supported by LCDproc and should make everything easier, nevertheless I"d really like to find a (solderless) solution to exploit that unused pins on the VGA hat.

So, aside from LCD2USB boards, I wonder which connection board (I2C?) is OK to connect the LCD display to the pins of the VGA hat (I prefer a solderless solution so I"d like to buy display + connection board yet assembled).

If you intend to use specific software then I suggest you contact the writer of the software to see if it can be configured to drive the LCD using only the gpio pins you have free.

As the software seems to be written to use usb, serial and parallel ports for connecting to the LCD you may find you will not be able to use it with the limited gpio you have free.

In addition it provides hardware timed PWM suitable for servos, LEDs, and motors and samples/timestamps GPIOs 0-31 up to 1 million times per second (default 200 thousand).

This more advanced library includes a GPIOFile and GPIOMem class. The GPIOMem requires compiling Mike McCauley"s bcm2835 library above in to a shared object.

This example uses the WiringPi Ruby Gem: http://pi.gadgetoid.co.uk/post/015-wiringpi-now-with-serial which you can install on your Pi with "gem install wiringpi"

SPI access requires being root, whereas GPIO access can be done as any user, as the underlying bcm2835 library (which must be installed) can use the /dev/gpiomem interface.

In addition it provides hardware timed PWM suitable for servos, LEDs, and motors and samples/timestamps gpios 0-31 up to 1 million times per second (default 200 thousand).

support I²C 23017 8/16/32/64/128 GPIO, I²C TMP102 Temp sensor, I²C RTC DS1307, I²C ADC ADS1015, I²C PWM, I²C EEPROM 24c32, I²C BMP085 Barometric Pressure/Temperature/Altitude Sensor, GPIO input/output, DC motor, Relay, I²C 16x16 LED matrix, I²C 24x16 Matrix, 84x48 pixels LCD, 16x2 character LCD, 20x4 character LCD, 1-Wire 18B20 Temp Sensor, Ultra Sonic distance sensor, available from

Generic interface for GPIO or other I/O operations. The package allows user modules to be easily added and loaded, to interface with any I/O device. The code is written in Python and uses the scratchpy Python package to interface with Scratch.

The package is also documented in Issues 20 and 22 of The MagPi. RpiScratchIO is the basis of a new BrickPi Scratch handler, which is documented in Issue 23 of The MagPi.

This uses the Java library available at https://github.com/jkransen/framboos. It does not depend on (or use) the wiringPi driver, but uses the same numbering scheme. Instead it uses the default driver under /sys/class/gpio that ships with the distro, so it works out of the box. Any Java application that controls GPIO must be run as root.

This uses the Java Webapp available at https://bitbucket.org/sbub/raspberry-pi-gpio-web-control/overview. You can control your GPIO over the Internet. Any Java application that controls GPIO must be run as root.

For operating system versions prior to the raspbian Jessie release, the export and unexport of pins must be done as root. Since the raspbian Jessie release the pi user is a member of the group "gpio" and so control of the GPIO no longer requires a change to the root user. With Jessie, if using a script as in the code below, you"ll need to put a "sleep 1" command in between your "export" and "direction" commands to allow time for the operating system to set up the GPIO number specific direction file.

The GPIO pins are accessible from Lazarus without any third-party software. This is performed by means of the BaseUnix unit that is part of every distribution of Lazarus and Free Pascal or by invoking Unix shell commands with fpsystem. The following example uses GPIO pin 17 as output port. It is assumed that you created a form named GPIO17ToggleBox with a TToggleBox and a TMemo named LogMemo (optional, for logging purposes). The program has to be executed with root privileges.

It is a new BASIC featuring modern looping constructs, switch statements, named procedures and functions as well as graphics (Cartesian and turtle), file handling and more. It also supports the Pi"s on-board GPIO without needing to be run as root. (You do not need any special setup routines either)

The control words cannot be loaded directly into the 32 bit ARM registers with 32 bit addresses, as bwBASIC has no POKE and PEEK commands and other versions of BASIC only handle 8 bit registers with 16 bit addresses with these commands. So the GPIO pins need to be exported so that they exist in a file structure which can be accessed from basic with the OPEN command (ref 2).

Whilst bwbasic can accommodate shell commands, and we can store a set of these commands (eg. to export a number of GPIO pins at the outset) as numbered statements in a file that can be loaded with the basic command LOAD "filename" and RUN (ref 2), the shell commands have to run as a separate file, as they cannot be run from within, as part of a basic program.

Program to set 2 pins as outputs and 1 pin as input and to read the input turning on two different combinations of the two outputs (ie output 0,1 or 1,0) depending on the state of the input (1 or 0).

WebIOPi allows to control each GPIO with a simple web interface that can be used with any browser. Available in PHP and Python, they both require root access, but the Python version serves HTTP itself. Each GPIO pin can be set up as input or output and its LOW/HIGH stae can be changed. WebIOPi is fully customizable, so it can be used for home remote control. It also works over Internet. UART/SPI/I²C support will be added later. See code examples above.

In this tutorial we"ll take you through how to connect a 16x2 LCD display up to your Raspberry Pi using GPIO pins. Being able to display a message on the LCD is not only very cool but can be pretty useful too, for example in this tutorial we"ll cover how to get your LCD display to display the IP address of your raspberry Pi.

For this exercise we are going to control the LCD display using 4-bit mode. Whilst is is possible to connect to it in other ways using I2C or the UART this is the most direct method. In order to control the display in this way will we need to use 6 pins on the GPIO port, 4 data pins and 2 control pins.

Register Select – This toggles the Lcd display between two modes, Command mode (high) and Data mode (low). Command mode gives a Instruction to the LCD. Example – “Clear the display” , “Move cursor to home” etc and Data tells the LCD to display characters.

In order for the LCD to work we will wire the circuit up in a fashion similar to the diagram above, but hold off connecting everything together for now! The list below tells you exactly what the pins on the LCD connect to:

Begin assembling the circuit by inserting the Adafruit cobbler into the breadboard. Remember to straddle the cobbler over the centre of the breadboard so that no two pin is in the same row. Next insert the LCD display into the breadboard. Connect the 5V and GND pins from the cobbler to the top of breadboard and also connect Pins 1, 2, 15 on the LCD and 16 to their respective power rails. Your circuit should look similar to the picture below:

Connect the GPIO ribbon cable from the cobbler to the Pi, if everything is working correctly the back light on the LCD should turn on like on the picture above. If it doesn"t work check everything is wired up correctly

Next wire up the potentiometer. The middle pin of the potentiometer is connected to Pin 3 on the LCD display and the other two pins are connected to ground and 5V (it doesn"t matter which way round). Check the potentiometer is working by twisting the nob until you see boxes appear in the first line of the display like in the picture below:

In order to utilize the GPIO pins within Python you will need to Install the GPIO python library. Instructions on how to install the GPIO Python library can be found here.

To get the Python code to run the LCD display we are going to "grab" it from adafruit using GitHub. Make sure your Rasp berry Pi is connected to internet and we"ll use the git command to clone the python code. Run the following commands in the terminal to download the files.

Now we can test the display is working and it is wired up correctly. One of the files we downloaded Adafruit_CharLCD.py contains python class for LCD display control. It also contains a small piece of code so when the program is run it will display a message on the LCD.

If you are using Version 2 of the Raspberry pi you will need to edit the program slightly since pin #21 has now been changed to pin #27. Open the file Adafruit_CharLCD.py with Python or use nano  Adafruit_CharLCD.py command to edit the program within the terminal. Go to line 57 of the code and replace:

Feel free to dive into the code of the program and change what"s displayed on the LCD. To do so open the program to edit like before and scroll to the last line of the code:

Simply change what is  typed in the brackets after lcd.message() to display the text you want.  The command is used to wrap the text onto a new line. A neater way of doing this is to change the last part of the program to look like the following:

This way when you run the program you will be prompted by "type your message here" to enter a message via your keyboard, which will then be displayed on the LCD. This was done by defining a new variable "message" that is equal to the command raw_input(), which allows the user to manually enter text. The part within the brackets of the raw_input() command is simply printed on the computer screen to prompt you what to write.

Getting the LCD display to display some text of your choosing is cool but not that useful. Running the program Adafruit_CharLCD_IPclock_example.py will display the date/time and the IP address of the Pi on the LCD. The program calls upon the methods from the previous program Adafruit_CharLCD.py. Feel free to open the program to look at the coding. To do so open the program in python or use the command sudo nano Adafruit_CharLCD_IPclock_example.pyin the terminal.

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.

Alternatively, you can use any VNC Viewer software like RealVNC. (NOTE: I’ve used RealVNC Software for accessing the Raspberry Pi’s Desktop on my personal computer).

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.

The 3.5 inch LCD Display is directly pluggable into a Raspberry Pi and perfectly fits various Pi models from B+ to Raspberry Pi 3B+. It is a brilliant alternative for an HDMI monitor. When set up, it behaves as a human-machine interface enabling the user to prototype with the Raspberry Pi device anywhere at any time.

Obliterate the contents of flash. An example of a NO_FLASH binary (UF2 loaded directly into SRAM and runs in-place there). A useful utility to drag and drop onto your Pico if the need arises.

Runs the lwip-contrib/apps/ping test app under FreeRTOS in NO_SYS=0 (i.e. full FreeRTOS integration) mode. The test app uses the lwIP \em socket API in this case.

An LED blink with the pico_bootsel_via_double_reset library linked. This enters the USB bootloader when it detects the system being reset twice in quick succession, which is useful for boards with a reset button but no BOOTSEL button.

A copy of the TinyUSB device example with the same name, but with a CMakeLists.txt which demonstrates how to add a dependency on the TinyUSB device libraries with the Raspberry Pi Pico SDK

A window will pop up with different tabs to adjust settings. What we are interested is the Interfaces tab. Click on the tab and select Enable for SPI. At this point, you can enable additional interfaces depending on your project needs. Click on the OK button to save.

We recommend restarting your Pi to ensure that the changes to take effect. Click on the Pi Start Menu > Preferences > Shutdown. Since we just need to restart, click on the Restart button.

These represent SPI devices on chip enable pins 0 and 1, respectively. These pins are hardwired within the Pi. Ordinarily, this means the interface supports at most two peripherals, but there are cases where multiple devices can be daisy-chained, sharing a single chip enable signal.

The Serial 7-Segment display is particularly useful for testing serial interfaces, because it can accept command from a UART, SPI, or I2C. Make sure to solder header pins on the 7-segment display before wiring.

Which generates an executable spitest. When we run ./spitest, it will exercise each of the segments of the display. It illuminates a segment in each digit for 5 seconds, before moving to the next segment. It takes about 40 seconds overall.

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).

Unfortunately with systemd, we cannot tell exactly when the X system will start, and we cannot necessarily guarantee that a user will be logged in (unless you have enabled auto-login with sudo raspi-config). To account for this, we will brute force our program to restart (with Restart) every 10 seconds (with RestartSec) if it fails or exits. KillMode tells systemd to kill off any processes associated with our program if the service fails (or exits), and TimeoutSec=infinity means that we don"t ever want to stop trying to execute our program.

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:

Note that stopping the service should send a stop command (SIGTERM--terminate signal) to your program. In most cases, this should stop the service and your program. If your program does not stop, see below on stopping your program.

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:

Add any 16x2 or 20x4 LCD-screen with a Hitachi HD44780 controller using either a port expander connected through I2c or just wire through GPIO 4 or 8 bit.

1 LCD-screen Hitachi HD44780 controller (PCF8574, or MCP23008 or MCP23017) with an I2c port expander. Or just wire through GPIO 4 or 8 bit. We recommend using a LCD-screen with an I2c port expander as it uses less wire (only 4) and is faster and more stable.

If your LCD has a PCF8574T chip from Texas Instruments, its default I2C address is 0x27Hex. If your LCD has a PCF8574AT chip from NXP semiconductors, its default I2C address is 0x3FHex. So your LCD probably has an I2C address 0x27Hex or 0x3FHex.

Since the Raspberry Pi GPIO only handle 3.3v, it will therefore be a good idea to use a I2C-safe Bi-directional Logic Level Converter so you don’t fryed your pi.

R2: Potentiometers: 10K Ohms. Controls the contrast and brightness of the LCD. Using a simple voltage divider with a potentiometer, we can make fine adjustments to the contrast.

If your display is equipped with an IC2 module, it’s not that difficult to connect an LCD display to a Raspberry Pi. Learn with this tutorial how to connect and to program an 1602 LCD with a Raspberry Pi.

There are many types of LCD displays. In this tutorial we are using the popular and affordable 1602 LCD. The LCD has an IC2 module soldered on it (see the pictures below). If your LCD is of the same type, but has a different size, it won’t be a problem to continue with this tutorial. You’ll just have to correct some parameters in the Python script. But if it is from a different type or it has no I2C module, you better look for another tutorial.Prepare the hardware

– First, you need to have a Raspberry Pi running on the latest version of Raspberry Pi OS. This version includes “Thonny”. We’ll use this user-friendly IDE to write our Python code. If you’re not familiar with Python or with Thonny or GPIO-pins, I suggest to have a look at our tutorials “How to write your first Python program on the Raspberry Pi” and/or “How to use the Raspberry Pi GPIO pins” to have a quick introduction.

In this tutorial we are using the popular and quite basic 16×2 or 1602 LCD. It can display 16 characters per line on 2 lines. Each character is made from a matrix with 5×7 dots. It is equipped with a backlight for easy reading. Besides sending text, thanks to specific commands, we can give instructions to the display, as to switch on/off the backlight for example.

The display we use in this tutorial is equipped with a I2C-module (black part on the picture below). I2C is a communication protocol which allows an easier connection between the display and the Raspberry Pi. Indeed, instead of having to wire all the pins on the top of the screen, we only have to connect the display with 4 wires to our Raspberry Pi.

Each I2C device has its own I2C address. Often this address is hard-wired in the device and will vary from manufacturer to manufacturer. If you don’t know the address of your I2C device, connect the device to your Raspberry Pi (see the next step). Then, open a terminal window and enter following command :

If you bought one of our kits, the hexadecimal address of the LCD is ‘0x27’. We will need the I2C address from the display to insert it in our Python code.

Be careful ! Before starting to connect wires on the GPIO pins of your Raspberry Pi, make sure you properly shut down the Pi and removed the power cable from the board!

To avoid extensive and complicated code writing, libraries are often used. For our LCD, we will also be using a library. We found the most appropriate library at GitHub from Dave Hylands . As these files from this quite specific library don’t come automatically with Python, we have to install them ourselves.

So, before writing the code, we’ll have to upload the files to our Raspberry Pi. You can download a ZIP-folder containing the 2 files to be installed here.

Download and unzip the files. If you did this operation on your computer, upload the files to your Raspberry Pi. And if you don’t know how to do that, have a look at our tutorial ‘How to transfer files between Raspberry Pi and PC‘. Make sure you upload them in the same folder as the new file we will create for our main code. And don’t change the filenames of the library of course.

And before running the script, it’s important to adjust the contrast of your LCD. If the contrast isn’t adjusted well, it’s possible you don’t see appearing anything. You can adjust it by turning with a small screwdriver at the blue potentiometer at the back of your LCD (see the pictures here above). Make sure the backlight of the display is on to see the result. If the LCD’s contrast is adjusted right, you can just see the darker rectangles for the characters appear.

Besides the commands we used in the last lines of our script, there are more possibilities to communicate with the LCD. If you want to learn more about, have a look at this Github webpage.