arduino lcd display no text supplier

Thank you everyone for all your help! I thought I should post the finished product in case someone in the future has the same problem. You were all right, I"d counted in from the right on my board, not realising there were 18 connectors instead of 16 like on non-RGB boards, so my wiring was all kaput.

I appreciate your help in getting my LCD to display text, I have tried to watch tutorials and I don"t understand where I went wrong and was directed to this community, hoping someone can help.

just displays black boxes on lines 1 and 3 (at the highest level of contrast) and nothing other wise. It should display hello world on the first line and time in seconds since it started on the second line.This is how i have the pins wired:

I am attempting to get my lcd up and running to print out a simple hello world. I am able to get the display to turn on, but whenever I upload the program to the board it will not display text. I have attached pictures of my wiring on the breadboard and on the Arduino, picture of the lcd being on, the code I am running, and a link to the schematic I used.

EDIT: Sorry guys, I thought I changed my picture format. This should be viewable now!! Also, When I initially turn it on it will display boxes on half of the screen that will slowly fade, almost as if it is "dying" unsure if thats useful.

But as others have commented the Original Poster needs to edit the question to add more details about what has been connected to what and example code that proves that when the controller code changes a signal that change reaches the LCD module.

In this project we will only be using a LCD, Arduino uno, jumper wires to display text on the LCD. We will use the digital pin 6 to control the contrast value of the LCD. The function to display text on the lcd will be | lcd.print (“Your text here”) |

In this blog, we are going to display text in an LCD display Using Arduino UNO. Display units play an important role in establishing good communication between the human and machine worlds. And so they are a big part of embedded systems. In the previous blog, I explained only How to connect the LCD display to Arduino.

The 16×2 LCD will have a total of 32 characters 16 in 1st line and a further 16 in 2nd line. In  16×2  LCD  there are 16 pins overall if there is a backlight, 14 pins if there is no backlight In each character there are 50 pixels.

Now let’s build the circuit. A circuit layout can be described in several ways. For this project ( How To Connect LCD 16×2 Display ToArduino ), we are using a physical layout diagram similar to the one shown in the above figure 2.

We write all main programs in the main section as you see we use the setCursor() function which is used for setting the location at which text written to the LCD will be displayed. We also used the Lcd.begin() function which means we initialize the LCD screen of 16×2 (16×2 LCD means 16 characters can be shown per line and 2 of those lines exist).

Liquid Crystal displays or LCDs have been used in electronics equipment since the late 1970s.   LCD displays have the advantage of consuming very little current And they are ideal for your Arduino projects.

In this article and in the accompanying video I’ll show you how easy it is to add an LCD display to your next Arduino design. I’ll also show you a very popular Arduino Shield that has a keypad which you can use in your projects as well.

Today LCD displays are used in a variety of items from test equipment to televisions. They’re inexpensive and versatile, this makes them ideal for all sorts of designs.

LCD displays do not emit light. Instead they block the passage of light, like little windows which open and shut the let light through. The liquid crystals used inside LCD displays are sandwiched between two layers of polarized material. By changing the orientation of the liquid crystals they allow light to pass or they block the light entirely.

Because transmissive LCD displays (the type we will be using) work by blocking light they require a backlight. Several methods have been used to create back lights including electroluminescent panels and fluorescent tubes.   these days the most common form of backlight is an LED, in fact so-called LED televisions are usually just LCD screens with an LED backlight system.

Another type of LCD display, the passive-matrix display, does not require a backlight, it works using reflected light. This type of display is often found in digital watches.

The principles of liquid crystals were discovered in the late 1880s but work on Modern LCD displays did not begin until the mid-1960s. a number of patents were filed in the early 1970s and in 1973 the Sharp Corporation introduced LCD displays for calculators.

The first color LCD displays were developed in the early 1980s but production units were not commonly available until the mid-1990s. By the late 1990s LCD displays were quite common.

A number of LCD displays are available for experimenters. These low-cost monochrome displays are ideal for use with microcontrollers like the Arduino and micro computers like the Raspberry Pi.

These displays are available in a number of different configurations. The part number for the display generally relates to the number of rows and columns in the display.

Common display configurations include 16 x 2, 16 x 4 and 20 x 4.  All of these displays are used in a virtually identical fashion the only difference being the number of columns and rows they have.

The LCD1602 display module is a very popular and inexpensive LCD display.  It is available in a number of different colors such as blue yellow and green and can easily be connected to an Arduino or Raspberry Pi.

In operation data is sent down the parallel data lines for the display. There are two types of data that can be sent to the display. The first type of data are the ASCII characters which are to be displayed on the display. The other type of data are the control characters that are used to activate the various display functions.

Brightness– This is the input for the brightness control voltage, which varies between 0 and 5 volts to control the display brightness. On some modules this pin is labeled V0.

Because the LCD module uses a parallel data input it requires 8 connections to the host microcontroller for the data alone. Add that to the other control pins and it consumes a lot of connections.  On an Arduino Uno half of the I/O pins would be taken up by the display, which can be problematic if you want to use the I/O pins for other input or output devices.

In 4-wire mode the data is sent a half a byte at a time, thus requiring only 4 data connections. The upper half of the data input (D4 to D7) is used while the other pins are not connected to anything.

We will begin our experiments by hooking up the LCD1602 to an Arduino Uno and running a few of the example sketches included with the Arduino IDE.  This will allow you to get familiar with the display without needing to write any code.

We need to hookup our LCD display to our Arduino. The display can use any of the Arduino digital I/O pins as it has no special requirements, but if you hook it up as I’ve illustrated here you can run the example sketches without needing to make any modifications.

In addition to the LCD1602 display ands the Arduino Uno you will need a 10K trimpot ot potentiometer, this is used a s a brightness control for the display. You’ll also need a 220 ohm resistor to drop the voltage for the displays LED backlight.

The Arduino IDE includestheLiquidCrystallibraryand this library has a number of example sketches. I’ll go over three of them here but you can also try the other ones.

The sketch starts with a number of credits and a description of the required hardware hookup. You’ll note that this is the same hookup you just performed on your Arduino and LCD module.

We then initialize an object that we call “lcd” using the pinouts of the LCD display. If you decide to hook up your display to different pins then you’ll need to modify this section.

In the beginning of the loop we set our cursor to the first position in the second row. Note that the row numbers start with zero so the second row is row 1.

That ends the loop, so we start back at the top of the loop and repeat. The result will be a counter on the second line that counts seconds from the htime the Arduino was last reset.

Load the sketch up to your Arduino and observe your display. If you don’t see anything try adjusting the brightness control that you wired to the display.

The second example we will try isthe Scroll sketch. Scrolling is a useful technique when you can’t get your text to fit on one line of the LCD display.

In the loop the code demonstrates the use of thescrollDisplayLeftandscrollDisplayRightfunctions.  As their names imply they move the text in a left or right direction.

Finally the last counter moves the text 16 positions to the left again, which will restore it back to the center of the display. The loop then repeats itself.

Custom characters are useful when you want to display a character that is not part of the standard 127-character ASCII character set. Thi scan be useful for creating custom displays for your project.

A character on the display is formed in a 5 x 8 matrix of blocks so you need to define your custom character within that matrix. To define the character you’ll use thecreateCharfunctionof the LiquidCrystal library.  You are limited to defining a maximum of eight characters.

The Custom Character demonstration requires one additional component to be wired to the Arduino, a potentiometer (10K or greater) wired up to deliver a variable voltage to analog input pin A0.

As with the previous sketches we examined this one starts by loading theLiquidCrystallibrary and defining an object calledlcdwith the connection information for the display.  It then moves on to define the custom characters.

The last two arrays,amsUpandarmsDowndefine the shape of a little “stickman”, or “stickperson” if you want to be politically correct! This is done to show how we can animate a character on the display.

Finally the setup routine ends by printing a line to the first row of the LCD display. The line makes use of two of the custom characters, the “heart” and the “smiley”.

We begin by reading the value of the voltage on pin A0 using the ArduinoanalogReadfunction. As the Arduino has a 10-bit analog to digital converter this will result in a reading ranging from 0 to 1023.

We then use an Arduinomapfunction to convert this reading into a range from 200 to 1000. This value is then assigned to an integer calleddelayTime, which as its name implies represents a time delay period.

One thing you may have noticed about using the LCD display module with the Arduino is that it consumes a lot of connections. Even in 4-wire mode there are still a total of seven connections made to the Arduino digital I/O pins. As an Arduino Uno has only 14 digital I/O pins that’s half of them used up for the display.

In other cases you would need to resort to using some of the analog pins as digital pins or even moving up to an Arduino Mega which has many more I/O pins.

But there is another solution. Use the I2C bus adapter for the LCD display and connect using I2C.  This only consumes two I/O pins and they aren’t even part of the set of digital I/O pins.

The I2C or IIC bus is theInter Integrated Circuitbus. It was developed by Philips Semiconductors in 1982 for use in the television industry.  The idea was to allow the integrated circuits in televisions to “talk” to one another using a standard bus.

The bus has evolved to be used as an ideal method of communicating between microcontrollers, integrated circuits, sensors and micro computers.  You can use it to allow multiple Arduinos to talk to each other, to interface numerous sensors and output devices or to facilitate communications between a Raspberry Pi and one or more Arduinos.

Power– This can be either 5 Volts or 3.3 volts, depending upon the application. Note that there are many precautions that must be observed if you are interfacing a 3.3 volt and 5 volt I2C device on the same bus.

In I2C communications there is the concept of Master and Slave devices. There can be multiples of each but there can only be one Master at any given moment. In most Arduino applications one Arduino is designated Master permanently while the other Arduinos and peripherals are the Slaves.

The I2C Adapter for the LCD display is a tiny circuit board with 16 male header pins soldered to it. These pins are meant to be connected directly to the 16-pin connection on the LCD1602 display (or onto other displays that use the same connection scheme).

The device also has a 4-pin connector for connection to the I2C bus. In addition there is a small trimpot on the board, this is the LCD display brightness control.

Most of these devices have three jumpers or solder pads to set the I2C address. This may need to be changed if you are using multiple devices on the same I2C bus or if the device conflicts with another I2C device.

Most Arduino Unos also have some dedicated pins for I2C, these are internally connected to A4 and A5 and are usually located above the 14 digital I/O pins.  Some models of the Uno have additional I2C connectors as well.

Note how much easier it is to use the I2C connection, which does not consume any of the Arduino Unos 14 digital I/O pins. Since A4 and A5 are being used for the I2C bus they can’t be used as analog inputs in this configuration.

Not all I2C adapters have the same I2C address, Most have address 0x20 but some use address 0x27 or 0x3F. You can change the address of your adapter by shorting some of the solder pads on the board.

If you don’t know the address you’ll need to find it out before you can run the sketches I’m about to show you. Fortunately there is a simple way of doing this, thanks to the great work of Nick Gammon.

Load this sketch into your Arduino then open your serial monitor. You’ll see the I2C address of your I2C LCD display adapter. You can then make note of this address and use it in the sketches we’ll be looking at now.

In order to run the subsequent sketches you’ll need to install another library. This is theNewLiquidCrystallibrarywhich, as its name implies, is an improved version of the LiquidCrystal library packaged with your Arduino IDE.

Remember that you’ll need to know the address of your I2C adapter before you run this sketch, so if you don’t know it go back and run Nick Gammon’s I2C Scanner first.

The sketch starts by loading the ArduinoWirelibrary. This is the Arduino library that facilitates communications over I2C and it’s part of your Arduino IDE installation.

On the next line we define the connections to the LCD display module from the I2C Adapter,. Note that these are NOT the connections from the Arduino, they are the connections used by the chip on the adapter itself.

In setup we set the size of the display and then print “Hello world!” on the first line in the first position.  After a short delay we print “How are you?” on the second line.

The first demo flashes the backlight on and off four times by alternating the use of thebacklightandnobacklightfunctions.  When we are done we turn the backlight on again.

The next demo uses theautoscrollfunction to scroll some text.  We first print the text “Scroll demo – “ and then implement a counter to count from 0 to 9 while scrolling the text.

Load the sketch and run it on your Arduino. If you can’t get it to work check out the address and connection information to be sure you have it right.

We need to make a minor wiring adjustment to the hookup with our I2C adapter, specifically we will need to add a DHT22 temperature and humidity sensor into the circuit. The wiring is shown here:

As you can see the DHT22 is connected with its output tied to pin 7 of the Arduino. The other two connections are 5 volts and ground. Note that pin 3 of the DHT22 is not used.

This sketch also makes use of theDHTlibrary from Adafruit. We used this library in a previous article, “Using the HC-SR04 Ultrasonic Distance Sensor with Arduino” so you may want to take a look at that one in order to get it installed.

The key thing to note is that this library is dependant upon another Adafruit library, theirUnified Sensorlibrary. Both can be installed using the Library Manager in your Arduino IDE.

The sketch is similar to our demo sketch in that it creates an “lcd” object with the I2C and display connection information.  It also defines a couple of parameters for the DHT22 sensor, as well as some floating variables to hold the temperature and humidity values.

Note that this displays the temperature in Celsius. If you want to change this to Fahrenheit its a simple matter of using some math. The formula( temp * 1.8 ) + 32will convert the results to Fahrenheit.

So far we have used the LCD1602 display module for all of our experiments. For our final demonstration we’ll switch to a popular Arduino shield that contains a LCD1602 along with some push buttons.

The LCD Keypad Shield is available from several different manufacturers. The device fits onto an Arduino Uno or an Arduino Mega and simplifies adding an LCD display to your project.

The Reset button is simply connected to the Arduino Reset pin and works just like the Reset button on the Arduino itself. This is common on many shields as the shields physically cover the Reset button.

Instead the buttons are connected to a resistor array that acts as a voltage divider. The entire array is connected to the Arduino’s analog A0 pin.  One pin for five push buttons.

Note that the LCD is being used in 4-wire mode. The LCD itself is the same one used on the LCD1602 module, so all of the code for that module will work with the LCD Keypad Shield as well.

Now that you know how the LCD Keypad module works and which Arduino pins it uses all that remains is to install it onto your Arduino and load the demo sketch.

One thing – once the shield is installed on the Arduino you won’t have easy access to the unused I/O pins to connect any sensors or output devices you may want to use (although the demo sketch doesn’t need anything else connected).  There are a couple of ways to get around this:

Use a shield that exposes the pins for prototyping before you install the LCD Keypad shield. In the video associated with this article I use a “Screw Shield” that brings all of the Arduino I/O pins out to a series of screw connectors. There are other similar shields. Using one of these shields is the easiest way to work with the LCD Keypad shield, as well as other Arduino shields.

The sketch begins by including theLiquidCrystallibrary. You can use the original one or the one includes with theNewLiquidCrystallibrary.  We then set up an object with the LCD connections, note that these are just hard-coded as they won’t change.

Next we define a number of constants, one for each of the push buttons. Note that nothing is defined for the Reset button as it simply mimics the Arduino Reset button, however a constant is defined for the “none” condition.

After that we define a function calledread_LCD_buttons().  This function reads the value on analog port A0 and returns an integer corresponding to the button integers we defined earlier. Note that the function adds approximately 50 to each of the manufacturers specified values to account for intolerances in the resistors in the voltage divider.

We start the loop by placing the cursor 9 spaces over on the second line. We then use themillisfunction to display a counter that counts the time since the Arduino was reset. This is to test the Reset button.

We then call ourread_LCD_buttons()function and use it to display the value of the push button, right before the counter. Then we end the loop and do it again.

Load the code onto the Arduino and run it. You should see the value of each button as you press it, along with a counter that increments each second. If you press Reset the counter should reset itself back to zero.

As you can see LCD displays are pretty simple to use thanks to the availability of some excellent libraries for the Arduino.  As these displays are also very inexpensive they will make an ideal addition to many of your Arduino projects.

And finally the LCD Keypad Shield is a convenient method of adding both a display and a simple keypad to your project, no wiring or soldering required.

I"m using LCD for the first time and I"m unable to make it work. It lights the background but it does not show any text. I tried three times from the beginning, each time with a different tutorial, and none of the solutions worked. Is there any mistake in my wiring that I do not see?

If you’ve ever tried to connect an LCD display to an Arduino, you might have noticed that it consumes a lot of pins on the Arduino. Even in 4-bit mode, the Arduino still requires a total of seven connections – which is half of the Arduino’s available digital I/O pins.

The solution is to use an I2C LCD display. It consumes only two I/O pins that are not even part of the set of digital I/O pins and can be shared with other I2C devices as well.

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.

If you look closely you can see tiny rectangles for each character on the display and the pixels that make up a character. Each of these rectangles is a grid of 5×8 pixels.

At the heart of the adapter is an 8-bit I/O expander chip – PCF8574. This chip converts the I2C data from an Arduino into the parallel data required for an LCD display.

If you are using multiple devices on the same I2C bus, you may need to set a different I2C address for the LCD adapter so that it does not conflict with another I2C device.

An important point here is that several companies manufacture the same PCF8574 chip, Texas Instruments and NXP Semiconductors, to name a few. And the I2C address of your LCD depends on the chip manufacturer.

So your LCD probably has a default I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it.

Connecting an I2C LCD is much easier than connecting a standard LCD. You only need to connect 4 pins instead of 12. Start by connecting the VCC pin to the 5V output on the Arduino and GND to ground.

Now we are left with the pins which are used for I2C communication. Note that each Arduino board has different I2C pins that must be connected accordingly. On Arduino boards with the R3 layout, the SDA (data line) and SCL (clock line) are on the pin headers close to the AREF pin. They are also known as A5 (SCL) and A4 (SDA).

After wiring up the LCD you’ll need to adjust the contrast of the display. On the I2C module you will find a potentiometer that you can rotate with a small screwdriver.

Plug in the Arduino’s USB connector to power the LCD. 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.

To drive an I2C LCD you must first install a library called LiquidCrystal_I2C. This library is an enhanced version of the LiquidCrystal library that comes with your Arduino IDE.

The I2C address of your LCD depends on the manufacturer, as mentioned earlier. If your LCD has a Texas Instruments’ PCF8574 chip, its default I2C address is 0x27Hex. If your LCD has NXP Semiconductors’ PCF8574 chip, its default I2C address is 0x3FHex.

So your LCD probably has I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it. Luckily there’s an easy way to do this, thanks to the Nick Gammon.

But, before you proceed to upload the sketch, you need to make a small change to make it work for you. You must pass the I2C address of your LCD and the dimensions of the display to the constructor of the LiquidCrystal_I2C class. 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!

First of all an object of LiquidCrystal_I2C class is created. This object takes three parameters LiquidCrystal_I2C(address, columns, rows). This is where you need to enter the address you found earlier, and the dimensions of the display.

In ‘setup’ we call three functions. The first function is init(). It initializes the LCD object. The second function is clear(). This clears the LCD screen and moves the cursor to the top left corner. And third, the backlight() function turns on the LCD backlight.

After that we set the cursor position to the third column of the first row by calling the function lcd.setCursor(2, 0). 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_I2C 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.

Creating custom characters has never been easier! We have created a small application called Custom Character Generator. Can you see the blue grid below? You can click on any 5×8 pixel to set/clear that particular pixel. And as you click, the code for the character is generated next to the grid. This code can be used directly in your Arduino sketch.

After the library is included and the LCD object is created, custom character arrays are defined. The array consists of 8 bytes, each byte representing a row of a 5×8 LED matrix. In this sketch, eight custom characters have been created.

This tutorial shows how to use the I2C LCD (Liquid Crystal Display) with the ESP32 using Arduino IDE. We’ll show you how to wire the display, install the library and try sample code to write text on the LCD: static text, and scroll long messages. You can also use this guide with the ESP8266.

Additionally, it comes with a built-in potentiometer you can use to adjust the contrast between the background and the characters on the LCD. On a “regular” LCD you need to add a potentiometer to the circuit to adjust the contrast.

Before displaying text on the LCD, you need to find the LCD I2C address. With the LCD properly wired to the ESP32, upload the following I2C Scanner sketch.

After uploading the code, open the Serial Monitor at a baud rate of 115200. Press the ESP32 EN button. The I2C address should be displayed in the Serial Monitor.

Displaying static text on the LCD is very simple. All you have to do is select where you want the characters to be displayed on the screen, and then send the message to the display.

The next two lines set the number of columns and rows of your LCD display. If you’re using a display with another size, you should modify those variables.

Then, you need to set the display address, the number of columns and number of rows. You should use the display address you’ve found in the previous step.

To display a message on the screen, first you need to set the cursor to where you want your message to be written. The following line sets the cursor to the first column, first row.

Scrolling text on the LCD is specially useful when you want to display messages longer than 16 characters. The library comes with built-in functions that allows you to scroll text. However, many people experience problems with those functions because:

After reading the previous section, you should be familiar on how this sketch works, so we’ll just take a look at the newly created function: scrollText()

delayTime: delay between each character shifting. Higher delay times will result in slower text shifting, and lower delay times will result in faster text shifting.

The messageToScroll variable is displayed in the second row (1 corresponds to the second row), with a delay time of 250 ms (the GIF image is speed up 1.5x).

In a 16×2 LCD there are 32 blocks where you can display characters. Each block is made out of 5×8 tiny pixels. You can display custom characters by defining the state of each tiny pixel. For that, you can create a byte variable to hold  the state of each pixel.

In summary, in this tutorial we’ve shown you how to use an I2C LCD display with the ESP32/ESP8266 with Arduino IDE: how to display static text, scrolling text and custom characters. This tutorial also works with the Arduino board, you just need to change the pin assignment to use the Arduino I2C pins.

We hope you’ve found this tutorial useful. If you like ESP32 and you want to learn more, we recommend enrolling in Learn ESP32 with Arduino IDE course.

This article includes everything you need to know about using acharacter I2C LCD with Arduino. I have included a wiring diagram and many example codes to help you get started.

In the second half, I will go into more detail on how to display custom characters and how you can use the other functions of the LiquidCrystal_I2C library.

Once you know how to display text and numbers on the LCD, I suggest you take a look at the articles below. In these tutorials, you will learn how to measure and display sensor data on the LCD.

Each rectangle is made up of a grid of 5×8 pixels. Later in this tutorial, I will show you how you can control the individual pixels to display custom characters on the LCD.

They all use the same HD44780 Hitachi LCD controller, so you can easily swap them. You will only need to change the size specifications in your Arduino code.

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

Note that an Arduino Uno with the R3 layout (1.0 pinout) also has the SDA (data line) and SCL (clock line) pin headers close to the AREF pin. Check the table below for more details.

After you have wired up the LCD, you will need to adjust the contrast of the display. On the I2C module, you will find a potentiometer that you can turn with a small screwdriver.

The LiquidCrystal_I2C library works in combination with the Wire.h library which allows you to communicate with I2C devices. This library comes pre-installed with the Arduino IDE.

To install this library, go to Tools > Manage Libraries (Ctrl + Shift + I on Windows) in the Arduino IDE. The Library Manager will open and update the list of installed libraries.

*When using the latest version of the LiquidCrystal_I2C library it is no longer needed to include the wire.h library in your sketch. The other library imports wire.h automatically.

Note that counting starts at 0 and the first argument specifies the column. So lcd.setCursor(2,1) sets the cursor on the third column and the second row.

Next the string ‘Hello World!’ is printed with lcd.print("Hello World!"). Note that you need to place quotation marks (” “) around the text since we are printing a text string.

The example sketch above shows you the basics of displaying text on the LCD. Now we will take a look at the other functions of the LiquidCrystal_I2C library.

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.

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 tutorial, we will learn about scrolling long string of text on a character LCD, which can be tricky. A character LCD module has a small amount of RAM that can store text and supports the continuity of text scrolling across an LCD display. However, this requires a careful design of the embedded program.

In this tutorial, we will flash a long string of text on a character LCD from Arduino and review the different steps and concerns that should be considered.

Displaying long textDisplaying long strings of text on a character LCD is far from straight forward. The reason for this is that the display data RAM of character LCD modules is limited. For example, the display data RAM (DDRAM) of a 16×2 character LCD can store only 80 characters. In a two-line mode, the DDRAM can only store 40 characters per line. This means any attempt to store a text string greater than 40 characters will override the other line.

If you want to display and scroll text greater than 40 characters on a line of 16×2 LCD, the only way to do so is to break the original string into parts and write those parts of the text string to the DDRAM one by one, scrolling each part of the text string.

Another concern is maintaining continuity of the text that’s scrolling through the LCD. If only 40 characters per line can be written to an LCD module at one time, then only 16 characters can be displayed on the LCD at a time. To maintain the continuity of text scrolling across the LCD, some characters from the previous text segment need to be repeated in the next text segment that’s written to the DDRAM.

For example, on a 16×2 character LCD, if the text is scrolled one character per step, 15 characters from the current text segment will need to be repeated in the next text segment that’s written to the DDRAM. For other LCD modules, one less the number of characters per line needs to be repeated in the text segments. The size of the text segment that can be written to the DDRAM at a time depends on the number of characters per line that can be stored in the DDRAM of that LCD module.

So, let’s suppose the following text string has to be scrolled on a line of character LCD: “Quick brown fox jumps over the lazy dog Quick brown fox jumps over the lazy dog Quick brown fox jumps over the lazy dog “

The above string has 120 characters. Since only 40 characters can be written to the DDRAM at one time, 15 characters must be repeated from the previous text segment to maintain the continuity of text on a 16×2 LCD.

To display and scroll the above-given text string of 120 characters on a 16×2 LCD, it’s necessary to break it into five text segments of 40-character lengths (except for the last one) — with 15 (16-1) characters repeating in each consecutive segment. This is because each line displays 16 characters at a time while scrolling one character at a time.

The text segments from 1 to 4 have to be scrolled 24 (40-16) times as 40 characters are written to the DDRAM at a time. These characters are scrolled on a 16-character line while the last text segment should be scrolled however many times is the length of the segment in characters — plus additional padding (spaces) between each repetition of the scroll.

If you’re not adding any padding between the repeated text scroll, the text segment “5” needs to be scrolled 21 times (the length of the segment), or at least five times (21-16) as per choice.

The print() function is used to write textual data to the DDRAM of the character LCD. For scrolling a long text on a character LCD, the text can be broken up, as explained above, and each segment can be written to the DDRAM using the print() function.

It should be noted, however, that for scrolling text on the LCD, S/C, and RL bits of the “cursor or display shift,” the LCD command is set. Visit theto learn about LCD commands.

The scrollDisplayLeft() methodThis function scrolls the content from the display (the text and cursor) one space to the left. It needs no arguments. It simply scrolls the text written to the DDRAM by one space from the current DDRAM address (as in the address counter of the LCD).

The scrollDisplayRight() methodThis function scrolls the content of the display (the text and cursor) one space to the right. It needs no arguments. It simply scrolls the text written to the DDRAM by one space from the current DDRAM address (in the address counter of the LCD).

This function sets the direction of the text on a character LCD from left-to-right. It is the default direction of text. After calling this function, when the characters are written on the DDRAM of LCD, the characters will display from left to right. This function does not affect any previously displayed text. It only affects the text that’s passed to the LCD (via print or write function) after calling it.

This function sets the direction of the text on a character LCD from right-to-left. The default direction of the text is from left-to-right. After calling this function, when characters are written on the DDRAM of LCD, the characters will display from right to left. This function does not affect any previously displayed text. It only affects the text that’s passed to the LCD (via print or write function) after calling it.

The autoscroll() methodThis function serves to auto scroll the text of the LCD. The default direction of the text is from left to right. The direction of scrolling the text can be set using the leftToRight() function or the rightToLeft() function.

On calling this function, the text is scrolled from left-to-right or right-to-left by one space, according to the direction of text. Additionally, this function scrolls the text that’s written in the DDRAM. It does not alter the content of the DDRAM.

The command(), write() and send() methodsAll of the functions used to scroll the display of the character LCD use the command() method. This method is used to pass the LCD commands to the LCD module.

This method also uses another method — send() — to pass commands to the LCD. The command() method is used to pass commands to the LCD while the write() method is used to pass data to the LCD module (to write in the DDRAM).

The recipeIn this recipe, we will scroll long text of strings on a 16×2 character LCD. Two different strings will be scrolled on two lines of the 16×2 LCD.

One of the strings will scroll on the top line of the character LCD and repeatedly display, “EEWORLDONLINE.” The second string will scroll on the bottom line of the 16×2 LCD. It displays all of the websites of the EE Network with WTWH Media LLC.

Components required1. Arduino UNO x12. 16×2 character LCD x13. 10K Pot x14. 330 Ohms Resistor or any low-value resistor x15. Breadboard x16. Male-to-Male Jumper Wires or Connecting Wires

Circuit connectionsThe LCD module used in this project is JHD162A. This is a 16×2 LCD module with 5×8 character dots. The LCD module has a 16-pin interface. The LCD is interfaced with Arduino in a 4-bit mode. The pin 1 (GND) and 16 (LED) of the LCD module are connected to ground. Pin 2 (VCC) is connected to the VCC.

The pin 15 (LED+) of the LCD module is connected to the VCC via a small-value resistor. Pin 3 (VEE) is connected to the variable terminal of a pot while the fixed terminals of the pot are connected to ground and VCC.

The R/W pin is connected to ground because Arduino will only write data to the LCD module. The RS, EN, DB4, DB5, DB6, and DB7 pins of the LCD are connected to pins 13, 11, 7, 6, 5, and 4 of Arduino UNO, respectively. The breadboard is supplied to the common ground and the 5V supply rail from one of the ground pins and the 5V pin of Arduino UNO.

The goal is to display two strings on a 16×2 LCD module. One of the strings just displays the text “EEWORLDONLINE” on line 0 of the LCD. While scrolling on the display, this text must also scroll continuously on line 0. The text is repeated in a long string with two spaces between each repetition of the text.

“eeworldonline.com  edaboard.com  electro-tech-online.com  engineersgarage.com  analogictips.com  connectortips.com  microcontrollertips.com  powerelectronictips.com  sensortips.com  testandmeasurementtips.com  wireandcabletips.com  designfast.com  5gtechnologyworld.com”

After the third line segment, the string segments 1 to 3 begin repeating to enable the repeating text display, “EEWORLDONLINE.” All of the above three text-segments are 40-characters long and need to be scrolled 24 times (40-16) on a line of the 16×2 LCD.

All of the text segments are 40-characters long except the last one because the maximum capacity of the LCD’s DDRAM is 40 characters per line. Each subsequent text segment starts by repeating the last 15 characters of the previous text segment to ensure continuity of the scrolling text on the display.

A total of 15 characters are repeated because each line of the display has 16 characters and on scrolling by one space, the last 15 characters must match with the previous text segment whenever new data is written to the DDRAM. Each text segment is scrolled 24 times (40-16) as there are 40 characters stored on the DDRAM at one time and 16 characters are displayed on a line at a time on the LCD. The last line is scrolled according to the number of characters in it. This means it is scrolled less than 24 times.

The result is a scrolling display on 16×2 LCD that highlights EEWORLDONLINE on line 0 and all of the websites that are a part of the EE network on line 1.

Programming guideThe Arduino sketch starts importing the LiquidCrystal library. Then, an object defined by the variable “lcd” is defined of the LiquidCrystal class.

In the loop() function, the LCD display is first cleared using the clear() method, and the cursor is set at column 0 of the line 0, using the setCursor() method.

The text ” EEWORLDONLINE EEWORLDONLINE EEWORLDO” is printed using the print() method on the “lcd” object. Similarly, the text “”eeworldonline.com engineersgarage.com ” is printed at column 0 of line 1.

Next, a for loop is run in which the entire display is shifted left by using the scrollDisplayLeft() method 24 times. After scrolling the display on the LCD, a delay of 300 milliseconds each time is provided using the delay() function.

Similarly, the other text segments are displayed and scrolled. On line 0, three text segments are repeated continuously until the last trimmed text segment is displayed. On line 1, 11 text segments are displayed and scrolled. The last text segment on both lines is scrolled five times, according to the length of the text segments.

The body of the loop() function keeps repeating itself until Arduino is shutdown. Therefore, both long strings keep scrolling on lines 0 and 1 of the LCD module.

Arduino lacks support for C-style string manipulation functions. Otherwise, the sketch could be reduced to a few lines by storing the entire string to a variable and then trimming the string in each step for passing to the DDRAM of the LCD module. Even if the standard C’s string library might have been supported, the use of the string manipulation function would have increased the footprint of the embedded program.

We come across Liquid Crystal Display (LCD) displays everywhere around us. Computers, calculators, television sets, mobile phones, and 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 a display of 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 backward 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 the command register, whereas RS=1 for the data register.

Command Register: The command register stores the command instructions given to the LCD. A command is an instruction given to an 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, the data register is selected.

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