Want your Arduino projects to display status messages or sensor readings? Then these LCD displays might be the perfect fit. They are extremely common and a fast way to add a readable interface to your project. This tutorial will cover everything you need to know to get up and running with Character LCDs.
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Want your Arduino projects to display status messages or sensor readings? Then these LCD displays might be the perfect fit.
They are extremely common and a fast way to add a readable interface to your project. This tutorial will cover everything you need to know to get up and running with Character LCDs.
It is basically a display unit which uses liquid crystals to produce a visible image. When current is applied to this special kind of crystal, it turns opaque blocking the backlight that lives behind the screen.
As a result that particular area will become dark compared to other. If you look closely, you can actually see the little rectangles for each character on the display and the pixels that make up a character. Your code may have to adjust to the larger size but at least the wiring is the same!
Using a simple voltage divider with a potentiometer, we can make fine adjustments to the contrast. Basically this pin is used to differentiate commands from the data. For example, when RS pin is set to LOW, then we are sending commands to the LCD like set the cursor to a specific location, clear the display, scroll the display to the right and so on. E Enable pin is used to enable the display.
D0-D7 Data Bus are the pins that carries the 8 bit data we send to the display. To calculate the value of the series resistor, look up the maximum backlight current and the typical backlight voltage drop from the data sheet. And as you rotate the knob on the potentiometer, you should notice the first line of rectangles appear. If this happens, Congratulations! Your LCD is doing just fine.
But, the good news is that not all these pins are necessary for us to connect to the Arduino. We know that there are 8 Data lines that carry raw data to the display. This saves us 4 pins! Because in 8-bit mode you write the data in just one go. However, in 4-bit mode you have to split a byte in 2 nibbles, shift one of them 4 bits to the right, and perform 2 write operations. Try the sketch out and then we will dissect it in some detail.
The sketch starts by including LiquidCrystal library. As mentioned earlier in this tutorial, the Arduino community has a library called LiquidCrystal that makes programming the LCD module less difficult. Next we have to create an LiquidCrystal object.
Now that you have declared a LiquidCrystal object, you can access special methods aka functions that are specific to the LCD. This is used to specify the dimensions of the display i. You got the point! The second function is clear. Following that we will set the cursor position to second row, by calling function setCursor The cursor position specifies the location where you need the new text to be displayed on the LCD. There are a few useful functions you can use with LiquidCrystal object.
Few of them are listed below:. If you are finding characters on the display dull and unexciting, you can create your own custom characters glyph 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. CGRAM is another memory that can be used for storing user defined characters. This RAM is limited to 64 bytes. To use createChar you first set up an array of 8 bytes.
Whereas, the zeros and ones in the byte indicate which pixels in the row should be on and which ones should be off. Creating custom character was not easy until now! We have created a small application called Custom character generator for character LCD. Can you see the blue grid below? And as you click on pixels, the code for the character is generated next to the grid.
This code can directly be used in your Arduino sketch. Your imagination is limitless. The only limitation is that the LiquidCrystal library supports only eight custom characters.
In the setup we have to create the custom character using the createChar function. This function takes two parameters. The first one is a number between 0 and 7 in order to reserve one of the 8 supported custom characters. The second parameter is the name of the array of bytes. Next in the loop, to display the custom character we use write function and as a parameter we use the number of the character we reserved.
Did you know? Adjusting LCD contrast by rotating potentiometer knob. Parameters: rs, enable, d4, d5, d6, d7 LiquidCrystal lcd 12 , 11 , 5 , 4 , 3 , 2 ;. Custom Character Generator.
Hitachi HD44780 LCD controller
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. 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. Check out the tutorial below if you want to use an I2C module as well:.
How to use a 16×2 character LCD with Arduino
HD44780 Character LCD
There are many of them out there, and you can usually tell them by the pin interface. This example sketch prints "Hello World! The LCDs have a parallel interface, meaning that the microcontroller has to manipulate several interface pins at once to control the display. The interface consists of the following pins:.
Interfacing 16×2 Character LCD Module with Arduino