code for lcd display in arduino for sale
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An LCD (Liquid Crystal Display) is a great way to display information in our Arduino Uno controller. We will be wiring and programming an alphanumeric, two rows with 16 characters on each row. The display has an LED (Light Emitting Diode) backlight with adjustable contrast.
This white and blue LCD will display “Hello World!” on the top line and temperature on the bottom line. The thermistor temperature circuit created last time will be displayed in both Celsius and Fahrenheit degrees. Let’s get started.
When you look at an LCD display, it is made up of a series of dots or pixels. Each of these pixels is a liquid crystal. If electricity flows through the liquid crystal it will change its structure and be more rigid. This rigidity will look darker than if no electricity is applied. If we use a light behind this LCD then the backlight will make the pixels more pronounced. So electricity on the pixel will block the light and no electricity will allow the light through. This contrast is what we see using an LCD display.
The LiquidCrystal.zip file came on the disk with the Arduino UNO R3 super starter kit. It can also be downloaded from the link below with the program. Select this library and then select open. This will add the library to the Arduino IDE (Integrated Development Environment).
This first part will set up the library and declare the variables for the LCD display unit. Using the Steinhart-Hart Equation we declare our variables and set the coefficients for the equation.
The LCD is set up with 16 characters and 2 lines. The cursor for the LCD display is set for the first character on the first line by default. We then print the message “ Hello, World!”.
The program will calculate the temperature in Celsius (T) and in Fahrenheit (TF). The LCD cursor is then set to the second row and column 0. We can then print our temperatures and units of measure.
You will see the ‘Hello World!’ and the current temperature in two units of measure displayed on the LCD. Hold the thermistor between your fingers to see how rapidly the temperature can be read.
If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLCs are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII, and Floating Point. To get this free article, subscribe to my free email newsletter.First Name:
– Arduino is an open-source platform used for building electronics projects. Arduino consists of both a physical programmable microcontroller and a piece of software, or IDE (Integrated Development Environment) that runs on your computer, used to write and upload computer code to the physical board.
– The Arduino platform unlike most previous programmable circuit boards, the Arduino does not need a separate programmer to load new code onto the board — you can simply use a USB cable. Additionally, the Arduino IDE uses a simplified version of C++, making it easier to learn to program.
– The open sources and extensible language: Arduino IDE is based on open source tool. The programming language used can be extended through the C++ library.
– The open source and expandable hardware: Arduino is based on Atmel’s ATMEGA 8-bit microcontrollers and its SAM3X8E and SAMD21 32-bit microcontrollers. Development boards and modules are planned to be released under the premise of following the “Creative Commons License Agreement”, so experienced circuit designers can make their own modules and carry out corresponding expansions and improvements. Even users who are relatively inexperienced can make a trial version of the basic Uno development board, which is easy to understand the principle of its operation and save costs.
– The Arduino hardware and software were designed for artists, designers, hobbyists, hackers, newbies, and anyone interested in creating interactive objects or environments. Arduino can interact with buttons, LEDs, motors, speakers, GPS units, cameras, the internet, and even your smart-phone or your TV.
Arduino Leonardo: Arduino’s first development board to use one microcontroller with built-in USB. It is cheaper and simpler. The code libraries allow the board to emulate a computer keyboard, mouse, and more.
LCD means liquid crystal display. Basically, any displays can be used with Arduino, including alphanumeric character LCD display, monochrome graphic LCD display, color TFT LCD display, IPS LCD display. It can also be used for non LCD displays like: PMOLED display, AMOLED display, E-ink (E-paper) displays. Orient Display developed easy interface (SPI, I2C) displays which can be easily used with Arduino.
LCD displays were first used for watches and calculators. Now, LCD display technology dominants the display world, it can be found in wearables, smart homes, mobile phones, TVs, laptops, monitors, kiosks, aircraft cockpit, digital cameras, lab instrument, power grid etc.
LCD itself can emit light itself. It has to utilize outside light sources. LCD display module normally includes LCD glass (or LCD panel), LCD driving circuitry ( can be COG, COB or TAB) and a backlight.
A LCD display 16*2 is actually a basic and simple to use LCD module. It includes LCD glass, COB (Chip on PCB Board) LCD control board, backlight, zebra to connect LCD glass and control board and a bezel to hold everything together. 16×2 LCD display can display 16 characters per line and there are two lines. Each character has 5×7 dot matrix pixels and the cursor underneath. All 16×2 LCD display originally used standard Hitachi HD44780 driver. Of course the legendary HD44780 controller had EOL long time ago. All the 16×2 LCD displays use HD44780 compatible LCD controllers. Some of them are drop replacement, some of them need to modify the initialization code a little.
Pin4 (RS pin or Register Select/Control Pin): This pin toggles among command or data register, used to connect a microcontroller unit pin and obtains either 0 or 1(0 = data mode, and 1 = command mode).
Pin5 (Read/Write/Control Pin): This pin toggles the display among the read or writes operation, and it is connected to a microcontroller unit pin to get either 0 or 1 (0 = Write Operation, and 1 = Read Operation).
Pin 6 (Enable pin/Control Pin): This pin should be held high to execute Read/Write process, and it is connected to the microcontroller unit & constantly held high.
Pins 7-14 (Data Pins): These pins are used to send data to the display. These pins are connected in two-wire modes like 4-bit mode and 8-bit mode. In 4-wire mode, only four pins are connected to the microcontroller unit like 0 to 3, whereas in 8-wire mode, 8-pins are connected to microcontroller unit like 0 to 7.
A 16×2 LCD has two registers like data register and command register. The RS (register select) is mainly used to change from one register to another. When the register set is ‘0’, then it is known as command register. Similarly, when the register set is ‘1’, then it is known as data register.
Command Register: The main function of the command register is to store the instructions of command which are given to the display. So that predefined tasks can be performed such as clearing the display, initializing, set the cursor place, and display control. Here commands processing can occur within the register.
Data Register: The main function of the data register is to store the information which is to be exhibited on the LCD screen. Here, the ASCII value of the character is the information which is to be exhibited on the screen of LCD. Whenever we send the information to LCD, it transmits to the data register, and then the process will be starting there. When register set =1, then the data register will be selected.
The resistor in the diagram above sets the LED backlight brightness. A typical value is 220 Ohms resistor, but other values will work too. Smaller resistors will make the backlight brighter. The potentiometer is used to adjust the screen contrast. I typically use a 10K Ohm potentiometer, but other values will also work.
All of the code below uses the LiquidCrystal library that comes pre-installed with the Arduino IDE. A library is a set of functions that can be easily added to a program in an abbreviated format. In order to use a library, it needs be included in the program. Line 1 in the code below does this with the command #include
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 let’s 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.
The LiquidCrystal() 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 number of 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.
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:
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.
These two functions can be used together in the void loop() section to create a blinking text effect. This code will make the “hello, world!” text blink on and off.
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.
This function takes a string of text and scrolls it from right to left in increments of the character count of the string. For example, if you have a string of text that is 3 characters long, it will shift the text 3 spaces to the left with each step.
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 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 (°).
The detailed LCD tutorial can be found in the article. ARDUINO LCD SET UP AND PROGRAMMING GUIDE or to check https://github.com/arduino-libraries/LiquidCrystal
Usually, Arduino LCD display projects will run out of pin resources easily, especially with Arduino Uno. It can also be very complicated with the wire soldering and connections. This I2C 16x2 Arduino LCD Screen is using an I2C communication interface, meaning it only needs 4 pins from your microcontroller for the LCD display to run: VCC, GND, SDA, SCL.
The display comes with a "Gadgeteer" cable which you"ll probably not need as the Gadgeteer wiring system is no longer produced! The display does not come with a dedicated cable for the I2C connection - we just use standard jumper wires instead.
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.
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.
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.
D0-D7 (Data Bus) pins carry the 8 bit data we send to the display. For example, if we want to see an uppercase ‘A’ character on the display, we set these pins to 0100 0001 (as per the ASCII table).
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!
8-bit mode is much faster than 4-bit mode because it takes half the time. In 8-bit mode you write the data in one go. Whereas in 4-bit mode you have to split a byte into 2 nibbles and perform two write operations.
4-bit mode is often used to save I/O pins. However, 8-bit mode is best used when speed is required in an application and there are at least 10 I/O pins available.
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.
As discussed earlier in this tutorial a character is made up of a 5×8 pixel matrix, so you need to define your custom character within that matrix. You can use the createChar() function to define a character.
To use createChar() you first set up an array of 8 bytes. Each byte in the array represents a row of characters in a 5×8 matrix. Whereas, 0 and 1 in a byte indicate which pixel in the row should be ON and which should be OFF.
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.
Your imagination is limitless. The only limitation is that the LiquidCrystal library only supports eight custom characters. But don’t be discouraged, look at the bright side, at least we have eight characters.
In setup we need to create custom character using createChar() function. This function takes two parameters. The first parameter is a number between 0 and 7 to reserve one of the 8 supported custom characters. The second is the name of the array.
This module works with at least the LiquidCrystal I2C and LiquidCrystal_PCF8574 libraries available in the Arduino library manager. Address 0x3F worked for me since the A0, A1, and A2 jumpers are not shorted.
Recently purchased unit has a different address than the same part number purchased a year ago. It seems that if the small board is marked MH, the address is not going to be 0x27 or 0x20 but 0x3F. With that change of address, this display works and looks great.
Google for LCM1602 and you will find many pages that mention the board - including the pinouts stated above and sample programs using the Arduino library.
Heres the scoop. The library that works with this chip set is available at this link. http://www.play-zone.ch/en/fileuploader/download/download/?d=0&file=custom%2Fupload%2FFile-1345667375.zip
I liked the idea of the 4-wire interface, but I was disappointed that no documentation was available for this part. However after a night of hacking I got it to work with my Arduino Uno. I thought Id pass along the following information to spare others the trouble.
On the software side, you have to download and install a new LiquidCrystal_I2C library for Arduino, which has the capability to talk to the LCD display over the I2C bus. Heres a link to the library. Follow the example code for the DFRobot board, which turns out to have the same configuration as this LCD, and it should fire right up for you. The LCD has white characters on a backlit blue background, and looked great.
ERM1601SBS-1 is big 16 characters wide,1 row character lcd module,SPLC780C controller (Industry-standard HD44780 compatible controller),6800 4/8-bit parallel interface,single led backlight with white color included can be dimmed easily with a resistor or PWM,stn- blue lcd negative,white text on the blue color,wide operating temperature range,rohs compliant,built in character set supports English/Japanese text, see the SPLC780C datasheet for the full character set. It"s optional for pin header connection,5V or 3.3V power supply and I2C adapter board for arduino.
It"s easily controlled by MCU such as 8051,PIC,AVR,ARDUINO,ARM and Raspberry Pi.It can be used in any embedded systems,industrial device,security,medical and hand-held equipment.
Of course, we wouldn"t just leave you with a datasheet and a "good luck!".For 8051 microcontroller user,we prepared the detailed tutorial such as interfacing, demo code and Development Kit at the bottom of this page.
ERM2004FS-3 is small size 20 characters wide,4 rows character lcd module,SPLC780C controller (Industry-standard HD44780 compatible controller),6800 4/8-bit parallel interface,single led backlight with white color included can be dimmed easily with a resistor or PWM,fstn-lcd positive,black text on the white color,high contrast,wide operating temperature range,wide view angle,rohs compliant,built in character set supports English/Japanese text, see the SPLC780C datasheet for the full character set, It"s optional for pin header connection,5V or 3.3V power supply and I2C adapter board for arduino.
It"s easily controlled by MCU such as 8051,PIC,AVR,ARDUINO,ARM and Raspberry Pi.It can be used in any embedded systems,industrial device,security,medical and hand-held equipment.
Of course, we wouldn"t just leave you with a datasheet and a "good luck!".For 8051 microcontroller user,we prepared the detailed tutorial such as interfacing, demo code and Development Kit at the bottom of this page.
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The Arduino family of devices is features rich and offers many capabilities. The ability to interface to external devices readily is very enticing, although the Arduino has a limited number of input/output options. Adding an external display would typically require several of the limited I/O pins. Using an I2C interface, only two connections for an LCD character display are possible with stunning professional results. We offer both a 4 x 20 LCD.
The character LCD is ideal for displaying text and numbers and special characters. LCDs incorporate a small add-on circuit (backpack) mounted on the back of the LCD module. The module features a controller chip handling I2C communications and an adjustable potentiometer for changing the intensity of the LED backlight. An I2C LCD advantage is that wiring is straightforward, requiring only two data pins to control the LCD.
A standard LCD requires over ten connections, which can be a problem if your Arduino does not have many GPIO pins available. If you happen to have an LCD without an I2C interface incorporated into the design, these can be easily
The LCD displays each character through a matrix grid of 5×8 pixels. These pixels can display standard text, numbers, or special characters and can also be programmed to display custom characters easily.
Connecting the Arduino UNO to the I2C interface of the LCD requires only four connections. The connections include two for power and two for data. The chart below shows the connections needed.
The I2C LCD interface is compatible across much of the Arduino family. The pin functions remain the same, but the labeling of those pins might be different.
Located on the back of the LCD screen is the I2C interface board, and on the interface is an adjustable potentiometer. This adjustment is made with a small screwdriver. You will adjust the potentiometer until a series of rectangles appear – this will allow you to see your programming results.
The Arduino module and editor do not know how to communicate with the I2C interface on the LCD. The parameter to enable the Arduino to send commands to the LCD are in separately downloaded LiquidCrystal_I2C library.
The LiquidCrystal_I2C is available from GitHub. When visiting the GitHub page, select the Code button and from the drop-down menu, choose Download ZIP option to save the file to a convenient location on your workstation.
Before installing LiquidCrystal_I2C, remove any other libraries that may reside in the Arduino IDE with the same LiquidCrystal_I2C name. Doing this will ensure that only the known good library is in use. LiquidCrystal_I2C works in combination with the preinstalled Wire.h library in the Arduino editor.
To install the LiquidCrystal_I2C library, use the SketchSketch > Include Library > Add .ZIP Library…from the Arduino IDE (see example). Point to the LiquidCrystal_I2C-master.zip which you previously downloaded and the Library will be installed and set up for use.
Several examples and code are included in the Library installation, which can provide some reference and programming examples. You can use these example sketches as a basis for developing your own code for the LCD display module.
There may be situations where you should uninstall the Arduino IDE. The reason for this could be due to Library conflicts or other configuration issues. There are a few simple steps to uninstalling the IDE.
The I2c address can be changed by shorting the address solder pads on the I2C module. You will need to know the actual address of the LCD before you can start using it.
Once you have the LCD connected and have determined the I2C address, you can proceed to write code to display on the screen. The code segment below is a complete sketch ready for downloading to your Arduino.
The code assumes the I2C address of the LCD screen is at 0x27 and can be adjusted on the LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27,16,2); as required.
Similar to the cursor() function, this will create a block-style cursor. Displayed at the position of the next character to be printed and displays as a blinking rectangle.
This function turns off any characters displayed to the LCD. The text will not be cleared from the LCD memory; rather, it is turned off. The LCD will show the screen again when display() is executed.
After 40 spaces, the function will loop back to the first character. With this function in the loop part of your sketch, you can build a scrolling text function.
Scrolling text if you want to print more than 16 or 20 characters in one line then the scrolling text function is convenient. First, the substring with the maximum of characters per line is printed, moving the start column from right to left on the LCD screen. Then the first character is dropped, and the next character is displayed to the substring. This process repeats until the full string has been displayed on the screen.
The LCD driver backpack has an exciting additional feature allowing you to create custom characters (glyph) for use on the screen. Your custom characters work with both the 16×2 and 20×4 LCD units.
A custom character allows you to display any pattern of dots on a 5×8 matrix which makes up each character. You have full control of the design to be displayed.
To aid in creating your custom characters, there are a number of useful tools available on Internet. Here is a LCD Custom Character Generator which we have used.
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.
If we take a closer look at the display we can notice that there are small rectangular areas composed of 5×8 pixels grid. Each pixel can light up individually, and so we can generate characters within each grid.
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.
It has 16 pins and the first one from left to right is the Groundpin. The second pin is the VCCwhich we connect the 5 volts pin on the Arduino Board. Next is the Vo pin on which we can attach a potentiometer for controlling the contrast of the display.
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.
Next is the E pin which enables the writing to the registers, or the next 8 data pins from D0 to D7. So through this pins we are sending the 8 bits data when we are writing to the registers or for example if we want to see the latter uppercase A on the display we will send 0100 0001 to the registers according to the ASCII table. The last two pins A and K, or anode and cathode are for the LED back light.
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.
Here’s a simple code through which we can explain the working principle of the Liquid Crystal library. This is the code of the first example from the video:
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.
In case we have a text with length greater than 16 characters, we can scroll the text using the scrollDisplayLeft() orscrollDisplayRight() function from the LiquidCrystal library.
We can choose whether the text will scroll left or right, using the scrollDisplayLeft() orscrollDisplayRight() functions. With the delay() function we can set the scrolling speed.
The first parameter in this function is a number between 0 and 7, or we have to reserve one of the 8 supported custom characters. The second parameter is the name of the array of bytes.
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.
I hope you enjoyed this tutorial and learned something new. Feel free to ask any question in the comments section below and don’t forget to check out my full collection of 30+ Arduino Projects.