lcd screen circuit diagram in stock

We come across Liquid Crystal Display (LCD) displays everywhere around us. Computers, calculators, television sets, mobile phones, digital watches use some kind of display to display the time.

An LCD screen is an electronic display module that uses liquid crystal to produce a visible image. The 16×2 LCD display is a very basic module commonly used in DIYs and circuits. The 16×2 translates o a display 16 characters per line in 2 such lines. In this LCD each character is displayed in a 5×7 pixel matrix.

Contrast adjustment; the best way is to use a variable resistor such as a potentiometer. The output of the potentiometer is connected to this pin. Rotate the potentiometer knob forward and backwards to adjust the LCD contrast.

A 16X2 LCD has two registers, namely, command and data. The register select is used to switch from one register to other. RS=0 for command register, whereas RS=1 for data register.

Command Register: The command register stores the command instructions given to the LCD. A command is an instruction given to LCD to do a predefined task. Examples like:

Data Register: The data register stores the data to be displayed on the LCD. The data is the ASCII value of the character to be displayed on the LCD. When we send data to LCD it goes to the data register and is processed there. When RS=1, data register is selected.

Generating custom characters on LCD is not very hard. It requires the knowledge about custom generated random access memory (CG-RAM) of LCD and the LCD chip controller. Most LCDs contain Hitachi HD4478 controller.

CG-RAM address starts from 0x40 (Hexadecimal) or 64 in decimal. We can generate custom characters at these addresses. Once we generate our characters at these addresses, we can print them by just sending commands to the LCD. Character addresses and printing commands are below.

LCD modules form a very important in many Arduino based embedded system designs to improve the user interface of the system. Interfacing with Arduino gives the programmer more freedom to customise the code easily. Any cost effective Arduino board, a 16X2 character LCD display, jumper wires and a breadboard are sufficient enough to build the circuit. The interfacing of Arduino to LCD display below.

The combination of an LCD and Arduino yields several projects, the most simple one being LCD to display the LED brightness. All we need for this circuit is an LCD, Arduino, breadboard, a resistor, potentiometer, LED and some jumper cables. The circuit connections are below.

To establish a good communication between human world and machine world, display units play an important role. And so they are an important part of embedded systems. Display units - big or small, work on the same basic principle. Besides complex display units like graphic displays and 3D dispays, one must know working with simple displays like 16x1 and 16x2 units. The 16x1 display unit will have 16 characters and are in one line. The 16x2 LCD will have 32 characters in total 16in 1st line and another 16 in 2nd line. Here one must understand that in each character there are 5x10=50 pixels so to display one character all 50 pixels must work together. But we need not to worry about that because there is another controller (HD44780) in the display unit which does the job of controlling the pixels. (you can see it in LCD unit, it is the black eye at the back ).

In this tutorial, we are going to interface a 16x2 LCD with ARDUINO UNO. Unlike normal development boards interfacing an LCD to an ARDUINO is quite easy. Here we don’t have to worry about data sending and receiving. We just have to define the pin numbers and it will be ready to display data on LCD.

Note:We updated this tutorial and added some more additional information along with a step-by-step guide to interface 16x2 LCD withArduino. You can follow the below link for an updated tutorial.

In 16x2 LCD there are 16 pins over all if there is a back light, if there is no back light there will be 14 pins. One can power or leave the back light pins. Now in the 14 pins there are 8 data pins (7-14 or D0-D7), 2 power supply pins (1&2 or VSS&VDD or GND&+5v), 3rd pin for contrast control (VEE-controls how thick the characters should be shown), and 3 control pins (RS&RW&E).

In the circuit, you can observe I have only took two control pins, this gives the flexibility. The contrast bit and READ/WRITE are not often used so they can be shorted to ground. This puts LCD in highest contrast and read mode. We just need to control ENABLE and RS pins to send characters and data accordingly.

The ARDUINO IDE allows the user to use LCD in 4 bit mode. This type of communication enables the user to decrease the pin usage on ARDUINO, unlike other the ARDUINO need not to be programmed separately for using it in 4 it mode because by default the ARDUINO is set up to communicate in 4 bit mode. In the circuit you can see we have used 4bit communication (D4-D7).

First we need to enable the header file (‘#include ’), this header file has instructions written in it, which enables the user to interface an LCD to UNO in 4 bit mode without any fuzz. With this header file we need not have to send data to LCD bit by bit, this will all be taken care of and we don’t have to write a program for sending data or a command to LCD bit by bit.

Second we need to tell the board which type of LCD we are using here. Since we have so many different types of LCD (like 20x4, 16x2, 16x1 etc.). Here we are going to interface a 16x2 LCD to the UNO so we get ‘lcd.begin(16, 2);’. For 16x1 we get ‘lcd.begin(16, 1);’.

In this instruction we are going to tell the board where we connected the pins. The pins which are connected need to be represented in order as “RS, En, D4, D5, D6, D7”. These pins are to be represented correctly. Since we have connected  RS to PIN0 and so on as show in the circuit diagram, we represent the pin number to board as “LiquidCrystal lcd(0, 1, 8, 9, 10, 11);”. The data which needs to be displayed in LCD should be written as “ cd.print("hello, world!");”. With this command the LCD displays ‘hello, world!’.

In this Arduino tutorial we will learn how to connect and use an LCD (Liquid Crystal Display)with Arduino. LCD displays like these are very popular and broadly used in many electronics projects because they are great for displaying simple information, like sensors data, while being very affordable.

You can watch the following video or read the written tutorial below. It includes everything you need to know about using an LCD character display with Arduino, such as, LCD pinout, wiring diagram and several example codes.

An LCD character display is a unique type of display that can only output individual ASCII characters with fixed size. Using these individual characters then we can form a text.

The number of the rectangular areas define the size of the LCD. The most popular LCD is the 16×2 LCD, which has two rows with 16 rectangular areas or characters. Of course, there are other sizes like 16×1, 16×4, 20×4 and so on, but they all work on the same principle. Also, these LCDs can have different background and text color.

Next, The RSpin or register select pin is used for selecting whether we will send commands or data to the LCD. For example if the RS pin is set on low state or zero volts, then we are sending commands to the LCD like: set the cursor to a specific location, clear the display, turn off the display and so on. And when RS pin is set on High state or 5 volts we are sending data or characters to the LCD.

Next comes the R/W pin which selects the mode whether we will read or write to the LCD. Here the write mode is obvious and it is used for writing or sending commands and data to the LCD. The read mode is used by the LCD itself when executing the program which we don’t have a need to discuss about it in this tutorial.

After all we don’t have to worry much about how the LCD works, as the Liquid Crystal Library takes care for almost everything. From the Arduino’s official website you can find and see the functions of the library which enable easy use of the LCD. We can use the Library in 4 or 8 bit mode. In this tutorial we will use it in 4 bit mode, or we will just use 4 of the 8 data pins.

We will use just 6 digital input pins from the Arduino Board. The LCD’s registers from D4 to D7 will be connected to Arduino’s digital pins from 4 to 7. The Enable pin will be connected to pin number 2 and the RS pin will be connected to pin number 1. The R/W pin will be connected to Ground and theVo pin will be connected to the potentiometer middle pin.

We can adjust the contrast of the LCD by adjusting the voltage input at the Vo pin. We are using a potentiometer because in that way we can easily fine tune the contrast, by adjusting input voltage from 0 to 5V.

Yes, in case we don’t have a potentiometer, we can still adjust the LCD contrast by using a voltage divider made out of two resistors. Using the voltage divider we need to set the voltage value between 0 and 5V in order to get a good contrast on the display. I found that voltage of around 1V worked worked great for my LCD. I used 1K and 220 ohm resistor to get a good contrast.

There’s also another way of adjusting the LCD contrast, and that’s by supplying a PWM signal from the Arduino to the Vo pin of the LCD. We can connect the Vo pin to any Arduino PWM capable pin, and in the setup section, we can use the following line of code:

It will generate PWM signal at pin D11, with value of 100 out of 255, which translated into voltage from 0 to 5V, it will be around 2V input at the Vo LCD pin.

First thing we need to do is it insert the Liquid Crystal Library. We can do that like this: Sketch > Include Library > Liquid Crystal. Then we have to create an LC object. The parameters of this object should be the numbers of the Digital Input pins of the Arduino Board respectively to the LCD’s pins as follow: (RS, Enable, D4, D5, D6, D7). In the setup we have to initialize the interface to the LCD and specify the dimensions of the display using the begin()function.

The cursor() function is used for displaying underscore cursor and the noCursor() function for turning off. Using the clear() function we can clear the LCD screen.

So, we have covered pretty much everything we need to know about using an LCD with Arduino. These LCD Character displays are really handy for displaying information for many electronics project. In the examples above I used 16×2 LCD, but the same working principle applies for any other size of these character displays.

In this tutorial, I’ll explain how to set up an LCD on an Arduino and show you all the different ways you can program it. I’ll show you how to print text, scroll text, make custom characters, blink text, and position text. They’re great for any project that outputs data, and they can make your project a lot more interesting and interactive.

The display I’m using is a 16×2 LCD display that I bought for about $5. You may be wondering why it’s called a 16×2 LCD. The part 16×2 means that the LCD has 2 lines, and can display 16 characters per line. Therefore, a 16×2 LCD screen can display up to 32 characters at once. It is possible to display more than 32 characters with scrolling though.

The code in this article is written for LCD’s that use the standard Hitachi HD44780 driver. If your LCD has 16 pins, then it probably has the Hitachi HD44780 driver. These displays can be wired in either 4 bit mode or 8 bit mode. Wiring the LCD in 4 bit mode is usually preferred since it uses four less wires than 8 bit mode. In practice, there isn’t a noticeable difference in performance between the two modes. In this tutorial, I’ll connect the LCD in 4 bit mode.

BONUS: I made a quick start guide for this tutorial that you can download and go back to later if you can’t set this up right now. It covers all of the steps, diagrams, and code you need to get started.

Here’s a diagram of the pins on the LCD I’m using. The connections from each pin to the Arduino will be the same, but your pins might be arranged differently on the LCD. Be sure to check the datasheet or look for labels on your particular LCD:

Also, you might need to solder a 16 pin header to your LCD before connecting it to a breadboard. Follow the diagram below to wire the LCD to your Arduino:

The resistor in the diagram above sets the backlight brightness. A typical value is 220 Ohms, but other values will work too. Smaller resistors will make the backlight brighter.

Now we’re ready to get into the programming! I’ll go over more interesting things you can do in a moment, but for now lets just run a simple test program. This program will print “hello, world!” to the screen. Enter this code into the Arduino IDE and upload it to the board:

There are 19 different functions in the LiquidCrystal library available for us to use. These functions do things like change the position of the text, move text across the screen, or make the display turn on or off. What follows is a short description of each function, and how to use it in a program.

TheLiquidCrystal() function sets the pins the Arduino uses to connect to the LCD. You can use any of the Arduino’s digital pins to control the LCD. Just put the Arduino pin numbers inside the parentheses in this order:

This function sets the dimensions of the LCD. It needs to be placed before any other LiquidCrystal function in the void setup() section of the program. The number of rows and columns are specified as lcd.begin(columns, rows). For a 16×2 LCD, you would use lcd.begin(16, 2), and for a 20×4 LCD you would use lcd.begin(20, 4).

This function clears any text or data already displayed on the LCD. If you use lcd.clear() with lcd.print() and the delay() function in the void loop() section, you can make a simple blinking text program:

This function places the cursor in the upper left hand corner of the screen, and prints any subsequent text from that position. For example, this code replaces the first three letters of “hello world!” with X’s:

Similar, but more useful than lcd.home() is lcd.setCursor(). This function places the cursor (and any printed text) at any position on the screen. It can be used in the void setup() or void loop() section of your program.

The cursor position is defined with lcd.setCursor(column, row). The column and row coordinates start from zero (0-15 and 0-1 respectively). For example, using lcd.setCursor(2, 1) in the void setup() section of the “hello, world!” program above prints “hello, world!” to the lower line and shifts it to the right two spaces:

You can use this function to write different types of data to the LCD, for example the reading from a temperature sensor, or the coordinates from a GPS module. You can also use it to print custom characters that you create yourself (more on this below). Use lcd.write() in the void setup() or void loop() section of your program.

The function lcd.noCursor() turns the cursor off. lcd.cursor() and lcd.noCursor() can be used together in the void loop() section to make a blinking cursor similar to what you see in many text input fields:

Cursors can be placed anywhere on the screen with the lcd.setCursor() function. This code places a blinking cursor directly below the exclamation point in “hello, world!”:

This function creates a block style cursor that blinks on and off at approximately 500 milliseconds per cycle. Use it in the void loop() section. The function lcd.noBlink() disables the blinking block cursor.

This function turns on any text or cursors that have been printed to the LCD screen. The function lcd.noDisplay() turns off any text or cursors printed to the LCD, without clearing it from the LCD’s memory.

This function takes anything printed to the LCD and moves it to the left. It should be used in the void loop() section with a delay command following it. The function will move the text 40 spaces to the left before it loops back to the first character. This code moves the “hello, world!” text to the left, at a rate of one second per character:

Like the lcd.scrollDisplay() functions, the text can be up to 40 characters in length before repeating. At first glance, this function seems less useful than the lcd.scrollDisplay() functions, but it can be very useful for creating animations with custom characters.

lcd.noAutoscroll() turns the lcd.autoscroll() function off. Use this function before or after lcd.autoscroll() in the void loop() section to create sequences of scrolling text or animations.

This function sets the direction that text is printed to the screen. The default mode is from left to right using the command lcd.leftToRight(), but you may find some cases where it’s useful to output text in the reverse direction:

This code prints the “hello, world!” text as “!dlrow ,olleh”. Unless you specify the placement of the cursor with lcd.setCursor(), the text will print from the (0, 1) position and only the first character of the string will be visible.

This command allows you to create your own custom characters. Each character of a 16×2 LCD has a 5 pixel width and an 8 pixel height. Up to 8 different custom characters can be defined in a single program. To design your own characters, you’ll need to make a binary matrix of your custom character from an LCD character generator or map it yourself. This code creates a degree symbol (°):

This project is about connecting a screen from a laptop to the RIoTboard. For a full introduction, see part 1 by clicking here, it goes into more detail about this project. This part 2 covers the circuit and powering up the display.

The RIoTboard has a low-voltage differential signalling (LVDS) connector that sends data at very high speed (hundreds of MHz) in a serial form to an LCD display panel. The LCD display panel is responsible for deserializing the data back into a parallel format that the LCD display driver can understand. The advantage of this is that very few wires are required to transmit video from the RIoTboard to the LCD panel.

So, all that needs to be done is to connect up wires from the LVDS connector up to the LCD panel of choice. The LCD panel will require a certain voltage supply to operate. The backlight - often an LED backlight or a cold-cathode fluorescent lamp (CCFL) - will also require power. The particular LCD panel I used had a CCFL backlight and these require quite a high voltage (hundreds of volts) so an off-the-shelf inverter was used to generate this voltage. LED backlights require a far lower voltage.

The photo below shows the entire project, with everything taped to the back of the LCD panel to temporarily test everything out. The RIoTboard can be seen on the left (red board). Bottom-right is the main board I created which generates the required voltages to drive the LCD panel and the backlight.

There’s not much to the circuit except power supplies (on the board marked ‘Main Board’ in the photo above. The RIoTboard LVDS interface directly connects to the LCD display. The Main Board contains two main power supplies; one to drive the panel, and another for the backlight. The two voltages will vary depending on the panel chosen.

In order to have some flexibility, adjustable DC-DC converters were used so that they can be set to the desired voltages to suit different LCD panels. The DC-DC converters were off-the-shelf Texas Instruments (TI) modules, PTH04000WAH(step-down converter to drive the LCD panel) and PTN04050CAH(step-up to drive the backlight).

The LCD panel I used required 3.3V to function, and a 12-24V supply to drive the inverter to create the high voltage (HV) supply (>600V) for the cold cathode fluorescent lamp (CCFL). No inverter is needed for LED backlight panels.

The circuit for the two power supplies is shown below. The DC-DC converter U1 is used to generate a 3.3V supply to drive the LCD panel. U4 is used to step-up from 5V input up to 15V to drive the CCFL inverter which generates >600V. Different voltages can be set as can be seen in the table in the circuit diagram below (it depends on what input voltage the inverter requires), and the diagram shows the voltage set to 6V. In order to set to 15V, R12 should be 68 ohms, and R13 is not fitted.

The circuit has lots of ‘do not fit’ resistor locations that can be experimented with if it is desired to run the entire circuit and the RIoTboard from a single supply source.

The printed circuit board (PCB) that was created is shown below (the files are attached below so you can order your own from any PCB manufacturer). The board was designed to be cut into several pieces. The main board contains the two DC-DC converter modules and all associated circuitry. There is space for a variable resistor in case one is needed for dimming some displays.

The right side of the board is used to create some ‘breakout boards’. This is because it can be tricky making connections to the small connector on the LCD panel, and the mini LVDS connector on the RIoTboard. Therefore these small breakout boards are used to help with the connectivity.

There is also a small breakout board for a ‘digitizer’. This is because the LCD panel I selected has a Wacom digitizer covering the screen, for pen input. I wanted to attempt to use that with the RIoTboard too (I have not attempted it yet).

In theory many LCD panels should work. It was decided to select a slightly older panel with a reasonable resolution of 1024x768. Higher resolutions may require extremely high speed LVDS signalling and the wiring could get very critical.

More on that later, but it is probably easier to solder these wires on first (the wires are discussed next), and then solder the breakout board onto the LCD panel connector to end up with the result seen in the photograph above.

LVDS signalling is carried over pairs of wires. The communication from the RIoTboard to the LCD panel is carried over four pairs of wires. The cable is fairly critical. One option is to try Ethernet cable however in the end I decided to use the internals of a SATA cable. The photo below shows the insides of the cable with the plastic insulator stripped off. The cable has two pairs of wires. The outer screen and braid was removed, leaving just the twisted pairs with inner screen intact.

Once the connections were made, the copper ground wire was twisted around all the pairs to keep the screens all at the same voltage, and to keep a tidy bundle.

The RIoTboard uses a mini HDMI socket for LVDS signalling. A breakout board was created and soldered to a mini HDMI plug as shown here. This requires the printed circuit board thickness to be 0.8mm instead of the more usual 1.6mm.

The main board contains the two DC-DC converters mentioned earlier. The photo below shows what it looks like, assembled and taped onto the LCD panel. There is not a lot to the main board.

The particular LCD panel that I used had a CCFL backlight instead of an LED backlight. This meant that I needed an inverter to get from 15V to >600V. I purchased a cheap inverter (less than £3) from ebay (search for “5-28V 5mm Ultra-thin High Voltage Universal LCD Inverter for Laptop”). Here it is taped onto the LCD panel:

The 5V supply to the main board can now be connected up. Then, power up the RIoTboard. You should see an Android startup screen launch. Plug in a mouse, and you should be able to unlock the screen and begin using Android.

The information here will allow an LCD panel to be interfaced to the RIoTboard successfully. The next step is to create an enclosure to house it, so that the temporary wood stand can be finally discarded.

The main board also has space to connect up the digitizer portion of the LCD panel to the RIoTboard, so that pen capability can be enabled. That’s for another day too.

The full circuit diagram, parts list with order codes and plot (Gerber) files for the PCB are attached. The PCB files can be sent to any PCB manufacturer. Just specify that a 0.8mm thickness PCB is required.

Printing “Hello, world!” is usually the first thing that programming tutorials will have you do in a new language. This guide starts by blinking an LED, but now we’re going to print out real text using a Liquid Crystal Display (LCD).

Character LCDs are designed to show a grid of letters, numbers and a few special characters. This makes them great for printing data and showing values. When current is applied to this special kind of crystal, it turns opaque. This is used in a lot of calculators, watches and simple displays. Adding an LCD to your project will make it super portable and allow you to integrate up to 32 characters (16 x 2) of information.

Pin 3 on the LCD controls the contrast and brightness of the LCD. Using a simple voltage divider with a potentiometer, the contrast can be adjusted. As you rotate the knob on the potentiometer, you should notice that the screen will get brighter or darker and that the characters become more visible or less visible. The contrast of LCDs is highly dependent on factors such as temperature and the voltage used to power it. Thus, external contrast knobs are needed for displays that cannot automatically account for temperature and voltage changes.

If you look closely at the characters on the LCD, you will notice that they are actually made up of lots of little squares. These little squares are called pixels. The size of displays is often represented in pixels. Pixels make up character space, which is the number of pixels in which a character can exist.

Pay special attention to the component’s markings indicating how to place it on the breadboard. Polarized components can only be connected to a circuit in one direction.

The LCD has 16 pins, and it is polarized. The pins are numbered from left to right, 1 through 16. The LCD utilizes an extremely common parallel interface LCD driver chip from Hitachi called the HD44780. Thankfully, the Arduino community has developed a library to handle a great deal of the software-to-hardware interface. Below is a list of each of the pins on the LCD.

“Begin” the LCD. This sets the dimensions of the LCD that you are working with (16 x 2). It needs to be called before any other commands from the LCD library are used.

Move the cursor to the first space of the lower line lcd.setCursor(0,1);, then print the number of seconds that have passed since the RedBoard was last reset.

LiquidCrystal LCD_name(RS_pin, enable_pin, d4, d5, d6, d7);As with servos, you need to create an LCD object and give it a name (you can make more than one). The numbers in the brackets are pins on the RedBoard that connect to specific pins on the LCD.

lcd.setCursor(0,0);Move the cursor to a point on the 16x2 grid of characters. Text that you write to the LCD will start from the cursor. This line is starting back at position (0,0).

Count button pressesBy adding a button to the circuit, you can count the number of times the button was pressed or have the button change what the LCD is displaying. There could be many pages of information.

The screen is blank or flickeringAdjust the contrast by twisting the potentiometer. If it’s incorrectly adjusted, you won’t be able to read the text. Also, check the potentiometer, and make sure it"s connected correctly.

Rectangles in first rowIf you see 16 rectangles (like “█”) on the first row, it may be due to the jumper wires being loose on the breadboard. This is normal and can happen with other LCDs wired in parallel with a microcontroller. Make sure that the wires are fully inserted into the breadboard, then try pressing the reset button and adjusting the contrast using the potentiometer.

Still not working?Jumper wires unfortunately can go "bad" from getting bent too much. The copper wire inside can break, leaving an open connection in your circuit. If you are certain that your circuit is wired correctly and that your code is error-free and uploaded but you are still encountering issues, try replacing one or more of the jumper wires for the component that is not working.

Here’s a diagram of the pins on the LCD I’m using. The connections from each pin to the Arduino will be the same, but your pins might be arranged differently on the LCD. Be sure to check the datasheet or look for labels on your particular LCD:

Also, you might need to solder a 16 pin header to your LCD before connecting it to a breadboard. Follow the diagram below to wire the LCD to your Arduino:

The resistor in the diagram above sets the backlight brightness. A typical value is 220 Ohms, but other values will work too. Smaller resistors will make the backlight brighter.

This tutorial includes everything you need to know about controlling a character LCD with Arduino. I have included a wiring diagram and many example codes. These displays are great for displaying sensor data or text and they are also fairly cheap.

As you will see, you need quite a lot of connections to control these displays. I therefore like to use them with an I2C interface module mounted on the back. With this I2C module, you only need two connections to control the LCD. Check out the tutorial below if you want to use an I2C module as well:

These LCDs are available in many different sizes (16×2 1602, 20×4 2004, 16×1 etc.), but they all use the same HD44780 parallel interface LCD controller chip from Hitachi. This means you can easily swap them. You will only need to change the size specifications in your Arduino code.

For more information, you can check out the datasheets below. The 16×2 and 20×4 datasheets include the dimensions of the LCD and in the HD44780 datasheet you can find more information about the Hitachi LCD driver.

Most LCDs have a built-in series resistor for the LED backlight. You should find it on the back of the LCD connected to pin 15 (Anode). If your display doesn’t include a resistor, you will need to add one between 5 V and pin 15. It should be safe to use a 220Ω resistor, but this value might make your display a bit dim. You can check the datasheet for the maximum current rating of the backlight and use this to select an appropriate resistor value.

After you have wired up the LCD, you will need to adjust the contrast of the display. This is done by turning the 10 kΩ potentiometer clockwise or counterclockwise.

Plug in the USB connector of the Arduino to power the LCD. You should see the backlight light up. Now rotate the potentiometer until one (16×2 LCD) or 2 rows (20×4 LCD) of rectangles appear.

In order to control the LCD and display characters, you will need to add a few extra connections. Check the wiring diagram below and the pinout table from the introduction of this article.

We will be using the LCD in 4-bit mode, this means you don’t need to connect anything to D0-D3. The R/W pin is connected to ground, this will pull the pin LOW and set the LCD to WRITE mode.

To control the LCD we will be using the LiquidCrystal library. This library should come pre-installed with the Arduino IDE. You can find it by going to Sketch > Include Library > LiquidCrystal.

The example code below shows you how to display a message on the LCD. Next, I will show you how the code works and how you can use the other functions of the LiquidCrystal library.

After including the library, the next step is to create a new instance of the LiquidCrystal class. The is done with the function LiquidCrystal(rs, enable, d4, d5, d6, d7). As parameters we use the Arduino pins to which we connected the display. Note that we have called the display ‘lcd’. You can give it a different name if you want like ‘menu_display’. You will need to change ‘lcd’ to the new name in the rest of the sketch.

In the loop() the cursor is set to the third column and first row of the LCD with lcd.setCursor(2,0). Note that counting starts at 0, and the first argument specifies the column. If you do not specify the cursor position, the text will be printed at the default home position (0,0) if the display is empty, or behind the last printed character.

Next, the string ‘Hello World!’ is printed with lcd.print("Hello World!"). Note that you need to place quotation marks (” “) around the text. When you want to print numbers or variables, no quotation marks are necessary.

Clears the LCD screen and positions the cursor in the upper-left corner (first row and first column) of the display. You can use this function to display different words in a loop.

This function turns off any text or cursors printed to the LCD. The text/data is not cleared from the LCD memory. This means it will be shown again when the function display() is called.

This function turns on automatic scrolling of the LCD. This causes each character output to the display to push previous characters over by one space. If the current text direction is left-to-right (the default), the display scrolls to the left; if the current direction is right-to-left, the display scrolls to the right. This has the effect of outputting each new character to the same location on the LCD.

The following example sketch enables automatic scrolling and prints the character 0 to 9 at the position (16,0) of the LCD. Change this to (20,0) for a 20×4 LCD.

With the function createChar() it is possible to create and display custom characters on the LCD. This is especially useful if you want to display a character that is not part of the standard ASCII character set.

Technical info: LCDs that are based on the Hitachi HD44780 LCD controller have two types of memories: CGROM and CGRAM (Character Generator ROM and RAM). CGROM generates all the 5 x 8 dot character patterns from the standard 8-bit character codes. CGRAM can generate user-defined character patterns.

/* Example sketch to create and display custom characters on character LCD with Arduino and LiquidCrystal library. For more info see www.www.makerguides.com */

After including the library and creating the LCD object, the custom character arrays are defined. Each array consists of 8 bytes, 1 byte for each row. In this example 8 custom characters are created.

In this article I have shown you how to use an alphanumeric LCD with Arduino. I hope you found it useful and informative. If you did, please share it with a friend that also likes electronics and making things!

I would love to know what projects you plan on building (or have already built) with these LCDs. If you have any questions, suggestions, or if you think that things are missing in this tutorial, please leave a comment down below.

In this experiment, we will be building on the previous experiment by adding an LCD screen and writing a script to display the temperature sensor data on it. If you start thinking about how to run this in the background, we have something planned for that too!

The LCD screen is a 16x2 display, meaning it has 2 rows of 16 columns (characters). It has an LED backlight to illuminate the display even in the dark!

These screens are typically controlled by many parallel data lines, usually 11 or so. However, the one in your kit has additional circuitry that implements control of the screen with the I2C protocol, so you only need to use two data lines to control the screen!

I2C (Inter-Integrated Circuit), sometimes called IIC or Two-Wire Interface, is a serial interface used to quickly and easily connect multiple devices to controllers and processors such as the Omega2. Examples of I2C devices include:

To get this experiment up and running, we’ll be using the same temperature sensor circuit from the previous experiment, but we’ll also be connecting the I2C display to the Omega so we can display the temperature on it. The code we write will tie the two together, but the build will borrow heavily from the previous experiment.

The main sensor circuit is exactly the same as the previous experiment. If you’ve already taken it apart, no worries, just wire it back up exactly as before and you’ll be ready for the next step!

All done! If everything is connected properly, the LCD should light up with a bright green background and a row of black boxes on the top row. If it doesn’t light up, check that the jumper on the back of the LCD is firmly connected to the LED pins hanging off the side.

Wouldn’t it be nice if something could run the script for us every minute to actually update the LCD? We will get there in a bit, but for now, let’s take a look at how the code works.

In the code, we specifically use two main functions of the library: the constructor and i2c.write(). The constructor creates an I2C device object with the given address. The i2c.write() function then writes a list of bytes to the device’s address (without specifying the memory location on the device). The LCD display requires specific commands in order to activate its different write modes which the lcdDriver class wraps up nicely, making our final execution script quite compact.

Here we’re using two objects of different classes to accomplish our goal, TemperatureSensor and Lcd. If we had other devices we wanted to include in this experiment, we can write more class definitions and load them using the import statement.

To briefly explain, the asterisks (*) mean ‘for all instances’. The position of the asterisk corresponds to ‘minute’, ‘hour’, ‘date’, ‘month’, and ‘year’ in order from left to right. The path at the end is the script or command you want to run. Basically, this line tells cron to run the STK09-temperatureLCD.py script once a minute.

Do you want your Arduino projects to display status messages or sensor readings? Then these LCD displays can be a perfect fit. They are extremely common and fast way to add a readable interface to your project.

This tutorial will help you get up and running with not only 16×2 Character LCD, but any Character LCD (16×4, 16×1, 20×4 etc.) that is based on Hitachi’s LCD Controller Chip – HD44780.

When current is applied to these crystals, they become opaque, blocking the backlight that resides behind the screen. As a result that particular area will be dark compared to the others. And this is how the characters are displayed on the screen.

True to their name, these LCDs are ideal for displaying only text/characters. A 16×2 character LCD, for example, has an LED backlight and can display 32 ASCII characters in two rows of 16 characters each.

The good news is that all of these displays are ‘swappable’, which means if you build your project with one you can just unplug it and use another size/color LCD of your choice. Your code will have to change a bit but at least the wiring remains the same!

Vo (LCD Contrast) controls the contrast and brightness of the LCD. Using a simple voltage divider with a potentiometer, we can make fine adjustments to the contrast.

RS (Register Select) pin is set to LOW when sending commands to the LCD (such as setting the cursor to a specific location, clearing the display, etc.) and HIGH when sending data to the LCD. Basically this pin is used to separate the command from the data.

R/W (Read/Write) pin allows you to read data from the LCD or write data to the LCD. Since we are only using this LCD as an output device, we are going to set this pin LOW. This forces it into WRITE mode.

E (Enable) pin is used to enable the display. When this pin is set to LOW, the LCD does not care what is happening on the R/W, RS, and data bus lines. When this pin is set to HIGH, the LCD processes the incoming data.

Now we will power the LCD. The LCD has two separate power connections; One for the LCD (pin 1 and pin 2) and the other for the LCD backlight (pin 15 and pin 16). Connect pins 1 and 16 of the LCD to GND and 2 and 15 to 5V.

Most LCDs have a built-in series resistor for the LED backlight. You’ll find this near pin 15 on the back of the LCD. If your LCD does not include such a resistor or you are not sure if your LCD has one, you will need to add one between 5V and pin 15. It is safe to use a 220 ohm resistor, although a value this high may make the backlight a bit dim. For better results you can check the datasheet for maximum backlight current and select a suitable resistor value.

Next we will make the connection for pin 3 on the LCD which controls the contrast and brightness of the display. To adjust the contrast we will connect a 10K potentiometer between 5V and GND and connect the potentiometer’s center pin (wiper) to pin 3 on the LCD.

That’s it. Now turn on the Arduino. You will see the backlight lit up. Now as you turn the knob on the potentiometer, you will start to see the first row of rectangles. If that happens, Congratulations! Your LCD is working fine.

Let’s finish connecting the LCD to the Arduino. We have already made the connections to power the LCD, now all we have to do is make the necessary connections for communication.

We know that there are 8 data pins that carry data to the display. However, HD44780 based LCDs are designed in such a way that we can communicate with the LCD using only 4 data pins (4-bit mode) instead of 8 (8-bit mode). This saves us 4 pins!

The sketch begins by including the LiquidCrystal library. The Arduino community has a library called LiquidCrystal which makes programming of LCD modules less difficult. You can find more information about the library on Arduino’s official website.

First we create a LiquidCrystal object. This object uses 6 parameters and specifies which Arduino pins are connected to the LCD’s RS, EN, and four data pins.

In the ‘setup’ we call two functions. The first function is begin(). It is used to specify the dimensions (number of columns and rows) of the display. If you are using a 16×2 character LCD, pass the 16 and 2; If you’re using a 20×4 LCD, pass 20 and 4. You got the point!

After that we set the cursor position to the second row by calling the function setCursor(). The cursor position specifies the location where you want the new text to be displayed on the LCD. The upper left corner is assumed to be col=0, row=0.

There are some useful functions you can use with LiquidCrystal objects. Some of them are listed below:lcd.home() function is used to position the cursor in the upper-left of the LCD without clearing the display.

lcd.scrollDisplayRight() function scrolls the contents of the display one space to the right. If you want the text to scroll continuously, you have to use this function inside a for loop.

lcd.scrollDisplayLeft() function scrolls the contents of the display one space to the left. Similar to above function, use this inside a for loop for continuous scrolling.

If you find the characters on the display dull and boring, you can create your own custom characters (glyphs) and symbols for your LCD. They are extremely useful when you want to display a character that is not part of the standard ASCII character set.

CGROM is used to store all permanent fonts that are displayed using their ASCII codes. For example, if we send 0x41 to the LCD, the letter ‘A’ will be printed on the display.

CGRAM is another memory used to store user defined characters. This RAM is limited to 64 bytes. For a 5×8 pixel based LCD, only 8 user-defined characters can be stored in CGRAM. And for 5×10 pixel based LCD only 4 user-defined characters can be stored.