2 line 16 character lcd display free sample

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 is the main component in making custom characters. It stores the custom characters once declared in the code. CG-RAM size is 64 bytes providing the option of creating eight characters at a time. Each character is eight bytes in size.

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.

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.

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 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.

The first part of this article covers the basics of displaying text and numbers. 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 Arduino library.

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.

Scrolls the contents of the display (text and cursor) one space to the left. You can use this function in the loop section of the code in combination with delay(500), to create a scrolling text animation.

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.

When looking closely at the array, you will see the following. Each row consists of 5 numbers corresponding to the 5 pixels in a 5 x 8 dot character. A 0 means pixel off and a 1 means pixel on.

It is possible to edit each row by hand, but I recommend using this visual tool on GitHub. This application automatically creates the character array and you can click on the pixels to turn them on or off.

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.

Liquid Crystal Display(LCDs) provide a cost effective way to put a text output unit for a microcontroller. As we have seen in the previous tutorial, LEDs or 7 Segments do no have the flexibility to display informative messages.

This display has 2 lines and can display 16 characters on each line. Nonetheless, when it is interfaced with the micrcontroller, we can scroll the messages with software to display information which is more than 16 characters in length.

The LCD is a simple device to use but the internal details are complex. Most of the 16x2 LCDs use a Hitachi HD44780 or a compatible controller. Yes, a micrcontroller is present inside a Liquid crystal display as shown in figure 2.

It takes a ASCII value as input and generate a patter for the dot matrix. E.g., to display letter "A", it takes its value 0X42(hex) or 66(dec) decodes it into a dot matrix of 5x7 as shown in figure 1.

Power & contrast:Apart from that the LCD should be powered with 5V between PIN 2(VCC) and PIN 1(gnd). PIN 3 is the contrast pin and is output of center terminal of potentiometer(voltage divider) which varies voltage between 0 to 5v to vary the contrast.

Back-light: The PIN 15 and 16 are used as backlight. The led backlight can be powered through a simple current limiting resistor as we do with normal leds.

The Biomaker Stage-2 component pack contains a liquid crystal display (LCD) capable of displaying 2 lines of 16 characters (right). The device is equipped with an I2C interface backpack, that allows serial communication with the device. (This is the black-coloured circuit board soldered to the back of the green-coloured LCD board). The I2C interface allows communication with the LCD screen through two wires plus power supply, rather than 8+ wires required by a parallel port device. The I2C protocol allows comunication with multiple devices on the same 2 wire bus. Each device needs a unique address, usually set in the hardware.

The LCD display is powered by a 5V supply and draws about 25mA with the backlight on, and 2mA without. The green coloured backlight sits behind black coloured characters. The characters are formed in two lines of 16 characters in 5x7 dot matrices.

The display should be connected to the microcontroller via the Vcc (5V), Gnd (ground), SDA (data) and SCL (clock) wires. Because it is common to use multiple I2C devices, it is generally easier to connect through the breadboard, which allows multiple devices to share the I2C signals and power from the relevant sockets on the yellow connector on the microcontroller board.

XOD provides the software node text-lcd-16x2-i2c, that allows direct communication with the display, with inputs for each line of the display (see below). The address of the i2C device should be set at 27h using the ADDR parameter.

The text display can be a very useful tool for following program behaviour. In addition, XOD provides the watch node, a number of which can be connected to the outputs of key nodes, and provide real-time output of values as a programme is run in debug mode.

Advanced use: If you which to use multiple LCD displays on the I2C bus, you can add solder bridges to the jumpers A0, A1 and A2 on the I2C backpack - in order to change the address of each device, and allow them to be individually addressed. The supplied I2C backpack has a PCF8574T chip: and the IC address is (high order first) 0100 A2 A1 A0. When shipped, A2~A0 are all vacant. The default I2C address therefore: 0100 111 (0x27). If you want to modify the address yourself add the relevant jumpers, noting that floating address pad is 1, and the short circuit is 0 after adding a solder bridge.

Important: There is a potentiometer that controls the contrast setting of the display. It is a controlled by a black plastic wheel at the front left edge of the LCD screen. (Contrast can also be adjusted using the blue potentiometer on the I2C backpack). The contrast setting requires fine adjustment, and the screen will appear blank and unresponsive if badly adjusted. If, on first use, you want to check that the LCD screen is correctly connected (i.e. are using the correct I2C address), use a XOD node to switch the backlight on and off. If that works, load some text into the screen, and adjust the contrast for best legibility.

Previous examples connect the white LED backlight to power. The following example is specifically for those using an LCD with a RGB LED backlight. The only difference between the connection is the LED"s backlight on pins 15-18.

You are the BEST!!! Thank you. It was worth registering just to post this message to you. I hope to participate further. There are a LOT of bugs in the Arduino sketches (Projects 1-23). Thanks again.

Working OK with Picaxe 20x2 but uses pins I would like to have free for i2c. So, I am getting bigger picaxe to go with it. Used 2 rectifier diodes in series for the voltage drop to 4.2v on the backlight and two 1k ohm resisters in series for the contrast. Looks good.

Thanks loophole! I got the display working fine using this link that link that was mentioned, http://arduino.cc/en/Tutorial/LiquidCrystal, but it was dim since the backlight was not working. After reading loophole"s comment and looking at datafile I applied 4.2V pin 15 and grounded pin 16, and all was GREAT!

The post that KHartley posted with regards to all the pin connections and using an Aduino mini pro, who then also got a reply from member 468163, that the code and everything worked.

I am using the exact components and have followed the exact pin configurations for the past 2 weeks, connecting then reconnecting, I have also tried different FTDI cables for uploading onto the Arduino pro mini. BUT have had no success, PLEASE help me as it is a basic issue I am sure but cannot find the solution, My 16*2 LCD lights up and also when I upload a program the arduino page reads that it has successfully uploaded (Done Uploading).

We"ve had customers order face plates through Ponoko for these LCDs and be pretty happy with it. Check around on the comments on other products and on the forum. You"ll probably find a lot of different examples of mounting solutions.

can this run in 8bit mode? I"m trying so hard to just wire up the 8 data lines and manually send the bits required for certain symbols. But it"s either stuck in 4bit mode, or I"m completely lost. My program is simple and I KNOW that it is sending the 1"s and 0"s down the appropriate lines but I can"t get a response at all. And I can succesfully apply the example code for liquid crystal. In class we just banged some bits into those old lcd"s and got the expected response... Is this one more advanced or something? Thanks, I really appreciate any help.

No matter what line I set the cursor at using lcd.setCursor(0,0), or lcd.setCursor(0,1), it will print everything on line 0. I"ve used the same LCD, different size before and never had this issue.

You should make the LCD"s connection pins on the bottom, like on the RGB backlit LCD"s (https://www.sparkfun.com/products/10862). I like standing them straight up and down on breadboards. If I tried that with this one, it would be upside down.

I"m having a problem with this lcd, I can"d print custom caracters, I tried the code that this site http://icontexto.com/charactercreator/ gives you when you create a custom char, tried some other examples, but nothing, I always get just two vertical bars on the second and fourth columns.

I love this little LCD! It works great. However, I"m having a wicked hard time finding hardware (i.e. self-clinching PEM stud) that I can use to mount this. The 2.5mm mounting holes are pretty small. I"m trying hard not to use glues.

I"m having problems with my contrast - it"s always either too high (washed out characters) or too low (can"t see the character) on separate spaces at the same time. No matter how I adjust it, each character seems to require a different contrast level. Help, please?

I"m also having trouble with LCD. I hooked up at 10kOhm pot, but when I upload the code it just gives me random pixels and characters. Is my Atmega on my Arduino Uno shot?

Like others have said, works well with liquidcrystal library and I also like to pwm the backlight with a fet on the low side. Looks really cool to have it fade out to 1 or 2% duty cycle standby mode when there has been no button presses/input in a while and then fade back in when you press a button.

Also no external resistor is needed for the backlight; just like almost all other 5v character LCDs this one has a series resistor right on the board. Mine is 130 ohms.

I was able to achieve much better contrast by applying a slightly negative voltage on the Vo pin (3). Minus 200 mV did the trick. I seem to remember that LCD"s used to have a negative output for just this reason. I don"t know what the rating of this pin is, so proceed with caution.

3) If you hook it to an Arduino, powering the LED backlight from a digital I/O pin will only source 40mA max. (PIC micros are even less), any more and you are overloading your output. Tie pin K (or 16) to ground, and A (or 15) will be the high side. If you design for 40mA, calculate the current limiting resistor to put between the I/O pin and pin A (or 15) of the LED backlight as follows: 5V-4.2V=0.8V and 0.8V/0.040A=20ohms however, be sure to measure the voltage across your current limiting resistor and calculate the actual current flowing to the LED just in case... don"t overload your Arduino I/O!

4) If you want to really drive it properly, you need more POWER! So grab an NPN transistor such as a 2N4401 or 2N2222 or 2N3904, and amplify your I/O. Hook a 220 to 330 ohm resistor between your I/O and the base of the NPN, hook the emitter of the NPN to ground, and the collector to the K pin (or 16) of the LED backlight. Hook a 5 to 10 ohm 1/4W resistor between the A pin (or 15) of the LED backlight and the 5V rail (make sure your 5V regulator can handle the extra 120-160mA of current you are going to be consuming)

Thanks to the guy who first pointed that for that bcklight to work one needs pin 15 on +4.2V and pin 16 on ground. Without that I was getting a pretty dim job.

I made it work by using the same schematic featured in the LiquidCrystal Arduino library page, except LCD pin 6 is hooked to a digital PWM instead of a potentiometer for controlling contrast.

Pretty cool little LCD. I had some problems initially with the 4bit LCD library, but after finding that the standard LiquidCrystal library supports 4-bit data lines it worked great.

The one thing that threw me off was that the standard (not extended) datasheet mentions that the backlight (BKL) can be driven by pins 1,2 or 15,16 -- however I found that I needed to apply 4.2v to pins 15,16 before the backlight would work. Easy fix, just misleading on the datasheet.

I"m very impressed. I followed the connections from the data sheet and set them up the same way the LiquidCrystal "Hello World" example sketch calls for, and the display worked perfectly with my Arduino Duemilanove. It does take some playing with the contrast potentiometer, but I quickly found the perfect setting. The display is sharp, clear, and cool white letters on a black background.

Ordered mine a week ago and finally got around to playing with it. I used the included LiquidCrystal.h for Arduino to run this thing. Very easy to use once you get it up and running. To get the contrast working I used a 3.3Kohm resistor going to ground, looks amazing. Not quite as bright as picture but I think I"m close. 2.2Kohm is too washed out and 6.8 Kohm nothing shows up. I can"t believe how much easier this is compared to the 68HC12. Uhhh, I"m going to have nightmares for the rest of my life.

Have you wired in the backlight? That tutorial doesn"t include wiring pins 15 and 16 on the lcd. I have hooked the backlight up to a pwm output so that I can turn it on and off via sketch.

I am also ahving this same problem. The LCD was great and easy to set up, but the brightness is really really poor. I installed a pot and all, but no dice.

Has anyone got this working with the LiquidCrystal or LCD4bit library? I am having quite a bit of trouble getting it to work reliably and am at the point where I am going to try and code my own library for it.

I"m also having heaps of trouble. I can sometimes get it to display text, maybe once out of every 30 attempts. And IF it decides to display anything it ends up garbling the message and locking up, not displaying the other strings in the sequence. Is this the LCD, my Arduino or the library? I tried using LCD4bit and a modified LiquidCrystal and they all yield the same, frustrating results.

Late reply, but I have trouble with this if I forget to add decoupling capacitors on the V+ line. Especialy using multiple serial to parallel converters at high data rates.

Great little lcd, for basic output, debugging etc. Very easy to interface, and looks very slick! If you need a basic no frills LCD, this is a good buy.

Hey, great instructable. When I first saw the 2x16 display had 8 programmable characters, I was hoping large fonts or some graphics would be possible, but given the few characters, and only two lines to work with, I just assumed a big font would be impossible.

But wow, you did an amazing job making it look nice with minimal characters. Kudos. It was inspiring for me to contribute back some improvements. Very creative an minimalistic use of the corners and edge pieces.

- I added Space, period to get character additions rolling. But I got bored, and did a first crack at all the missing characters 0x20-0x5F (mostly punctuation). (A crazy Friday night here, I tell ya, a bit bleary-eyed near the end.) Some of the chars are pretty rough, it"d be great if Michael and/or others could improve upon them.

The C should be pretty straight forward; I use a few slightly advanced C pointer constructs, like "const char *(*p)[2]" (a variable v, which is a pointer, to an array of two pointers to const chars [an array of two string pointers]. There"s an art to understanding and creating C pointers like that; think reading from the inside outworks, working from right to left. Hard to explain, but good to understand to be able to do things efficiently.

(If you are tight for space, you could null out {"", ""} the definintions for characters that you aren"t using in your app. Even better, moving those arrays to PROGMEM (putting them in FLASH instead of prescious RAM) would save a lot, too. Unfortunately all the type-casting required to make PROGMEM arrays obfuscates the code too much. I erred on the side of readability.)

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This 16-character, 2-line parallel liquid crystal display achieves a large viewing area in a compact package. It features a yellow-green LED backlight and uses the common HD44780 interface (330k pdf), so sample interface code is widely available for a variety of microcontrollers. This LCD is also available without a backlight.

The DDRAM address 0x00 corresponds to the first character of the top line, address 0x0F corresponds to the last character of the top line, address 0x40 corresponds to the first character of the second line, and address 0x4F corresponds to the last character of the second line.

As shown in the diagram above, a potentiometer whose output is connected to Vo will allow you to set the contrast for optimal viewing of your display.

The backlight in this LCD is composed of LEDs in series. The total voltage drop across these LEDs is typically 4.2 V and the recommended current through the LEDs is 120 mA. You should use a current limiting resistor RLIMIT as shown above where:

Note: No cables or connectors are included with this product, but a 40×2-pin 0.100" male header strip and 20", 16-conductor ribbon cable can be purchased separately. You can break a 7×2 segment from the header strip and solder it to the 14 through-holes on the left side of the LCD PCB; the ribbon cable will then plug into the header pins (leaving two holes empty). The header pins won’t enforce proper orientation of the cable, so you will need to take care to plug it into the correct pins. The 8×2 shrouded box header can be used with this LCD if you use pliers to pull out connector pins 15 and 16, effectively turning it into a 7×2 keyed receptacle for a 16-conductor ribbon cable.

The Displaytech 162M series is a lineup of our largest 16x2 character LCD modules. These modules have a 122x44 mm outer dimension with 99x24 mm viewing area on the display. The 162M 16x2 LCD displays are available in STN or FSTN LCD modes with or without an LED backlight. The backlight color options include yellow green, white, blue, pure green, or amber color. Get a free quote direct from Displaytech for a 16x2 character LCD display from the 162M series.

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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.

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.

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.

In this simple sketch we show you the most useful and important functions from the LiquidCrystal_I2C library. So, let’s take a quick look at how the code works.

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:

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.

Then, in the setup(), create a custom character using the createChar() function. This function accepts as arguments a location to allocate the char and the char variable as follows:

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.