arduino lcd module quotation

I have an I2C OLED connected to my Arduino Uno and I have used it to display integers in past projects, but I would like to know how to place quotes around a variable (in this case Serial.read() ). My current solution displays strange characters around the text on the OLED, but if I use a constant non-changing variable the OLED doesn"t spit out a garbage character. Here"s my code:

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

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

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

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

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

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 . When you include a library in a program, all of the code in the library gets uploaded to the Arduino along with the code for your program.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This 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.

The LiquidCrystal Arduino library has many other built-in functions which you might find useful. You can find an overview of them below with explanation and some code snippets.

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

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

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

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

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

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

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

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

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

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

The LCDduino board enables users to create many applications/projects that require a 16×2 LCD display and Arduino. The board has the exact size of 16×2 LCD and can be installed on the backside of the LCD. This is a low-cost solution that has onboard Arduino + LCD so no extra Arduino Nano or Arduino board is required. The Arduino compatible hardware includes onboard programming and boot-loader connectors, Atmega328 microcontroller, and 16×2 LCD interface. Each Arduino I/O Pin including the VCC and GND is exposed to the connectors for easy connection with sensors and other devices. The board enables the easy interface of many devices and sensors. The operating power supply is 7 to 15V DC.

After the board assembly, the brand new Atmega328 microcontroller requires burning the bootloader before it can be programmed using Arduino IDE. Refer to the connection diagram and follow the links below to learn more about bootloader and Arduino IDE programming.

Arduino example code is provided below to test the project. This code will help you to convert this board into a 0 to 5V Voltmeter. Just connect the DC source at analog in A0 to measure the DC voltage.

ERM1602SBS-5 is 16 characters wide,2 rows character lcd module,ST7070 controller (Industry-standard HD44780 compatible controller),6800 4/8-bit parallel+3/4-wire serial spi 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 ST7070 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.

The LCDduino board enables users to create many applications/projects that require a 16×2 LCD display and Arduino. The board has the exact size of 16×2 LCD and can be installed on the backside of the LCD. This is a low-cost solution that has onboard Arduino + LCD so no extra Arduino Nano or Arduino board is required. The Arduino compatible hardware includes onboard programming and boot-loader connectors, Atmega328 microcontroller, and 16×2 LCD interface. Each Arduino I/O Pin including the VCC and GND is exposed to the connectors for easy connection with sensors and other devices. The board enables the easy interface of many devices and sensors. The operating power supply is 7 to 15V DC.

After the board assembly, the brand new Atmega328 microcontroller requires burning the bootloader before it can be programmed using Arduino IDE. Refer to the connection diagram and follow the links below to learn more about bootloader and Arduino IDE programming.

Arduino example code is provided below to test the project. This code will help you to convert this board into a 0 to 5V Voltmeter. Just connect the DC source at analog in A0 to measure the DC voltage.

In Arduino programming many times you will come with situations where you want to put double quotes in a string. For example sending AT command with double quotes. There many different methods let’s discuss one by one.

Information Station (Arduino): Welcome to my latest instructable to build a self contained information station! This awesome device uses an Arduino Uno with an ethernet shield t…

What is the purpose of declaring LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); if we are using pins A4 and A5? I know that 0x27 is the ic address but what is the rest for?

I am getting a error while i m going to add zip file of lcd library error id this zip file does not contains a valid library please help me to resolve this issue as soon as possible.....

Hey guys. My LCD works fine using the above instructions (when replacing the existing LCD library in the Arduino directory) but I can"t get the backlight to ever switch off. Suggestions?

This means that your string needs to have space for one more character than the text you want it to contain. That is why Str2 and Str5 need to be eight characters, even though "arduino" is only seven - the last position is automatically filled with a null character. Str4 will be automatically sized to eight characters, one for the extra null. In Str3, we"ve explicitly included the null character (written "\0") ourselves.

It is often convenient, when working with large amounts of text, such as a project with an LCD display, to setup an array of strings. Because strings themselves are arrays, this is in actually an example of a two-dimensional array.

Hi, i have and LCD 16x2 connected to my Leonardo. I works properly with all the examples son the connection is ok. But I add the LCD to another sketch and it"s just showing garbage, and i have no idea why. I just want to show "Writing:" in the first row, and the variable nombrearchivo in the second row. All of this works using serial, so my only problem is the LCD.

In 4 bit mode, the host and the LCD must remain in nibble sync. If they lose nibble sync with each other, it will never recover so the LCD will start to see garbage commands.

So if the library is in 4 bit mode and you power cycle only the LCD, the host (arduino) and the LCD will not be in the same mode (LCD in 8 bit mode, host in 4 bit mode) and the LCD will see garbage commands.

In 8 bit mode, it is still possible to get glitches on the display, but since things are done byte at a time there is no nibble synchronization issue so any effects of noise should be short lived and future commands to the LCD should continue to work.

The lcd.clear function is slow and can lead to screen flicker especially if done every time through loop(). Overwrite old data with spaces, reset the cursor position and print the new data and only update the screen when the data changes will help prevent flicker.

I"m tearing my hair out trying to get my project to work. I have an Arduino Uno R3 clone (Freetronics 100% compatible) with a 20x4 I2C LCD from DX (part number GY-LCD-V1). I also have four pushbuttons connected via the analog pins (in digital mode.) Other than that I have nothing connected to the arduino other than power via USB to my Mac.

Initially I thought this might be a memory problem. The sketch is big (about 28KB compiled without debug/info defines) and very nearly 32Kb with them compiled in. Free RAM is about 800bytes according to the debug statements. I"ve been mounting the hardware (LCD + buttons so far) in an enclosure, and I had a few days of the sketch running flawlessly, but now it"s back to the normal problems.

In the previous tutorial, we discussed scrolling long text strings on a character LCD using Arduino. However, it’s also possible to display custom characters on the LCD. These custom characters are user-defined and are stored in Character Generator RAM (CGRAM) of the LCD module.

Custom charactersThe character LCDs support ASCII characters that serve as a standard set of characters. The patterns for the supported characters are already stored in the memory (CGROM) of the LCD module. For printing these standard characters, the controller simply needs to “pass” the associated data register value to the address counter of the LCD.

That data register value is, then, stored in the DDRAM and the address counter is updated (and increased or decreased depending on the direction of the text). When the LCD has to print a character, it reads the value from the DDRAM, compares it with CGROM, and prints the character by generating the stored pattern for that character.

Sometimes it’s necessary to print user-defined characters/icons on an LCD. For example, you may be using an LCD module in a communication device and need to print a custom character showing the status of the connectivity. A character LCD may be embedded in a battery-operated device and it may be necessary to display the level of charging by using a custom icon.

The LCD modules, apart from DDRAM, have the CGRAM to store user-defined characters. To generate a custom character/icon, it’s necessary for the controller needs to pass the entire character pattern to the LCD module. This character pattern is stored in the CGRAM of the LCD. A 16×2 LCD module typically has enough CGRAM to store a pattern for 8 characters/icons.

The pattern for custom characters is defined as a group of 7, 8, or 10 bytes, depending on the number of rows of pixels for each character on the LCD. Each byte represents a row of pixels that form the character. The bits of the byte represents the status of the pixels (i.e. whether the respective pixels will turn on or off).

For example, on a 16×2 LCD, each character is printed as 5×8 dots. Therefore, 8 bytes (for 8 rows of pixels) are used to represent a character and 5 LSBs of each byte are used to turn on or off the pixels.

CGRAMMost of the character LCD modules use an HD4478 controller. There can be a different LCD controller on an LCD module. To know what controller is used in an LCD module, simply refer to its data sheet.

Depending on the size of the character LCDs, they have different DDRAM and CGRAM. For example, a 16×2 LCD has 80 bytes of DDRAM and 64 bytes of CGRAM. As there are 8 rows of pixels for each character, the pattern for 8 characters of 5×8 dots can be stored on the CGRAM.

The CGRAM addresses start from 0x40. The first character is stored from address 0x40 to 0x47. This custom character can be printed at the current cursor position by sending the command ‘0’ to the LCD module. The second custom character is stored from the address 0x48 to 0x4F. It can be printed at the current cursor position by sending the command 1 to the LCD module.

Generating custom charactersIt’s fairly easy to create a custom character. Simply determine the pixel map of the character and, then, determine the bytes that should be written to the CGRAM to generate that character/icon. For a 16×2 LCD, which has 5×8 dots characters, the top three MSB for each byte can be ignored. The top three MSBs can be set to 0 in each byte while other bits can be set to 0 or 1, according to the pixels that should turn off or on.

Generating custom charactersTo create custom characters, typically the LCD command must first be set and the CGRAM address needs to be passed. Next, the LCD command to write data to the CGRAM needs to be passed.

When using Arduino, it’s even simpler to create a custom character/icon. The LiquidCrystal library on the Arduino platform has a function createChar() that creates custom characters and icons on an LCD. This function takes the position of the custom character and an array of bytes as an argument. The generated custom character can be flashed on an LCD at the current cursor position by using the write() or print() function.

The createChar() mskethodThe createChar() function creates a custom character/icon for use on an LCD. Essentially, it writes a user-defined character pattern (a pixel map of the character) to a given CGRAM address.

The position of the character is specified as a number. For example, in the case of 16×2 LCD, 8 custom characters can be defined and their position can be 0 to 7.

The write() methodThe write() function writes a character on an LCD. The character is written (displayed) at the current cursor position and the cursor is moved right or left according to the direction of text on LCD.

If the data passed is a string (quoted in double or single quotes) of ASCII characters, it is written as such. If it’s a number, the character corresponding to that position in the CGRAM is written on the LCD.

The print() methodThe print() method is used to print text to an LCD. If a custom character has to be written on the LCD using the print() method, then the char() function (with the position of the custom character as the argument), must be passed as the argument of the print() function.

Components required1. Arduino UNO x12. A 16×2 character LCD x13. A 10K Pot x14. A 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 withArduinoin a 4-bit mode.

The LCD module is connected with Arduino in 4-bit mode. The LCD is first initialized and the display is cleared to get rid of any garbage values in the DDRAM.

The patterns for 16 different custom characters are then generated by defining their pixel maps as arrays. Eight of these custom characters can be displayed on the LCD at one time. This is because 64 bytes of the CGRAM of the 16×2 LCD can store a pattern for only 8 characters at any time.

The 8 custom characters are generated by defining their character maps. The cursor position on the LCD is set from column 0 of line 0 to column 7 of line 0, and each character is displayed one by one. Then, the next 8 custom characters are generated and they’re displayed on line 0 of the LCD at the cursor positions from columns 0 to 7.

In the loop() function, the first 8 custom characters are generated using the customChar() method. The cursor position is set by using the setCursor() method. Each character is printed on the LCD by using the print() method at the cursor positions of column 0 to 7 of line 0, one after the other.

After the printing of the 8 characters, a two-second delay is provided using the delay() function. Then, the LCD is cleared by using the clear() method.